Using the Bosch injectors
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Re: Using the Bosch injectors
I just replaced mine with injectors from south bay fuel injectors, followed the instructions, (added the second o ring), and just returned from a 1000+ mile trip with no problems. They will work just fine. Randy
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Re: Using the Bosch injectors
You bought the wrong Bosch injectors. Send them back and get the Bosch III's from FIC (Fuel Injector Connection). The ones that they make are flow balanced and are longer (same size as stock). They're the only people I know that make the injectors longer than a regular Bosch injector would be.
http://fuelinjectorconnection.com/shop/
http://fuelinjectorconnection.com/shop/
#4
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Re: Using the Bosch injectors
You bought the wrong Bosch injectors. Send them back and get the Bosch III's from FIC (Fuel Injector Connection). The ones that they make are flow balanced and are longer (same size as stock). They're the only people I know that make the injectors longer than a regular Bosch injector would be.
http://fuelinjectorconnection.com/shop/
http://fuelinjectorconnection.com/shop/
They fit by using a second oring. It acts as a spacer. There is no magic!! Sold thousands of these injectors, NEVER NEVER had a problem.
SHOW ME A PICTURE!
![crazy](https://www.thirdgen.org/forums/images/smilies/crazy.gif)
#5
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Re: Using the Bosch injectors
www.southbayfuelinjectors.com
info@southbayfuelinjectors.com
516-492-6504
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Re: Using the Bosch injectors
It is very simple. If you were to purchase a set of the bosch injectors we can send them set up with the second oring which will make them "plug n play". Or, if you prefer, we can send a written copy of installation instructions with a picture along with the additional orings that you may need. If we can help you in any way please do not hesitate to contact us!
www.southbayfuelinjectors.com
info@southbayfuelinjectors.com
516-492-6504
www.southbayfuelinjectors.com
info@southbayfuelinjectors.com
516-492-6504
Where do the additional orings go ?
Thanks
#11
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Re: Using the Bosch injectors
Looking at the injector from the bottom up, you have the plastic oring retainer, above that is the first oring, then above that oring there is a little groove, that is where the second oring goes. (By the way, we use the GM orings on all of our injectors)
When you install them, they need to go into the intake manifold first, in doing so you forget about that additional oring and install them as you would any other injector. The second oring is only there to act as a spacer, they DO NOT go down into the intake, this will give you the additional 1/8 to 1/4" in length that is missing!
You will never have a problem with leakage!!!!!
We guarantee them to fit without a problem as long as they are installed properly!!
It is our pleasure to share this info with everyone to make life easier and give some insight once and for all when it comes to these injectors.
If you order the bosch design lll's from us you will either receive a copy of the installation instructions along with the additional orings (no charge) or we can send them out to you with the orings already in place!![Smilie](https://www.thirdgen.org/forums/images/smilies/smile.gif)
![Smilie](https://www.thirdgen.org/forums/images/smilies/smile.gif)
Hope this picture helps.
When you install them, they need to go into the intake manifold first, in doing so you forget about that additional oring and install them as you would any other injector. The second oring is only there to act as a spacer, they DO NOT go down into the intake, this will give you the additional 1/8 to 1/4" in length that is missing!
You will never have a problem with leakage!!!!!
We guarantee them to fit without a problem as long as they are installed properly!!
It is our pleasure to share this info with everyone to make life easier and give some insight once and for all when it comes to these injectors.
If you order the bosch design lll's from us you will either receive a copy of the installation instructions along with the additional orings (no charge) or we can send them out to you with the orings already in place!
![Smilie](https://www.thirdgen.org/forums/images/smilies/smile.gif)
![Smilie](https://www.thirdgen.org/forums/images/smilies/smile.gif)
Hope this picture helps.
![Name: Backup_of_InsertSB-1.jpg
Views: 668
Size: 10.5 KB](https://www.thirdgen.org/forums/attachments/tpi/430535d1501505258-using-bosch-injectors-backup_of_insertsb-1.jpg)
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Re: Using the Bosch injectors
Beware !!!
I Don't want to chime here for nothing,im very picky when injector installation procedures are at play here,i don't play with FIRE,period.-
I have to say it but ,Southbay,last month you were selling RUSTED injectors.-
Now what would happen if Trinamo install the injectors he posted above and add
an extra oring ? That will leak as hell and he will probably burn the car.-
Trinamo,sorry to chime like this.-
Southbay,i have to get into,because i have had problems with injectors on my jeeps
and when they catch fire its no fun,believe me its no fun and you want to do whatever
it takes to put the fire down.-
This is no game,why you keep giving WRONG installation instructions ?
I Swear i cannot believe you are telling this guy to install additional orings
on those injectors !
Remember THIS THREAD ?
Remember this product you were selling ?
![](http://img139.imageshack.us/img139/4724/injectors20in20fuel20ra.jpg)
Sorry,but are you a pyromaniac ?
I Don't want to chime here for nothing,im very picky when injector installation procedures are at play here,i don't play with FIRE,period.-
I have to say it but ,Southbay,last month you were selling RUSTED injectors.-
Now what would happen if Trinamo install the injectors he posted above and add
an extra oring ? That will leak as hell and he will probably burn the car.-
Trinamo,sorry to chime like this.-
Southbay,i have to get into,because i have had problems with injectors on my jeeps
and when they catch fire its no fun,believe me its no fun and you want to do whatever
it takes to put the fire down.-
This is no game,why you keep giving WRONG installation instructions ?
I Swear i cannot believe you are telling this guy to install additional orings
on those injectors !
Remember THIS THREAD ?
Remember this product you were selling ?
![](http://img139.imageshack.us/img139/4724/injectors20in20fuel20ra.jpg)
Sorry,but are you a pyromaniac ?
#16
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Car: 87 Vette
Engine: 355/195AFR/SR/219CAM/1.6
Transmission: TH700R4/Vigilante
Axle/Gears: D44/3.45
Re: Using the Bosch injectors
FYI, ours are flow balanced also, and they are the same exact injector!!! I have yet to see a picture of one of their "longer" bosch design lll injectors side by side with a stock injector. This is all I hear and all I read about. Tell me how you take a factory made bosch injector and make it longer??? What do they do..stretch it! LOL
They fit by using a second oring. It acts as a spacer. There is no magic!! Sold thousands of these injectors, NEVER NEVER had a problem.
SHOW ME A PICTURE!![crazy](https://www.thirdgen.org/forums/images/smilies/crazy.gif)
They fit by using a second oring. It acts as a spacer. There is no magic!! Sold thousands of these injectors, NEVER NEVER had a problem.
SHOW ME A PICTURE!
![crazy](https://www.thirdgen.org/forums/images/smilies/crazy.gif)
check this out
![](http://img199.imageshack.us/img199/4897/injector.jpg)
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Re: Using the Bosch injectors
I think you've more than made your point, such that it is. If you want injectors to look brand new, then buy new they're only 3 times as expensive..... BTW, you're the only one I can recall that has burned down two vehicles. Given that, you might reconsider your declared expertise in this area.
The second o-ring is not a safety issue IMO, it's just a spacer to help hold the injector higher into the fuel rail. Pushing the injector deeper into the intake is not going to ensure a better seal, especially fuel wise since the bottom is just a vacuum seal.
The second o-ring is not a safety issue IMO, it's just a spacer to help hold the injector higher into the fuel rail. Pushing the injector deeper into the intake is not going to ensure a better seal, especially fuel wise since the bottom is just a vacuum seal.
#18
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Re: Using the Bosch injectors
You know, you have been breaking my chops long enough. First of all we gladly refunded that guys money for those injectors, and you know what, you can call that rust, but when we received them it was dirt. These injectors are USED they are not perfect. Funny, none of my customers cars ever blew up!!!!!!!!!
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Re: Using the Bosch injectors
I think you've more than made your point, such that it is. If you want injectors to look brand new, then buy new they're only 3 times as expensive..... BTW, you're the only one I can recall that has burned down two vehicles. Given that, you might reconsider your declared expertise in this area.
The second o-ring is not a safety issue IMO, it's just a spacer to help hold the injector higher into the fuel rail. Pushing the injector deeper into the intake is not going to ensure a better seal, especially fuel wise since the bottom is just a vacuum seal.
The second o-ring is not a safety issue IMO, it's just a spacer to help hold the injector higher into the fuel rail. Pushing the injector deeper into the intake is not going to ensure a better seal, especially fuel wise since the bottom is just a vacuum seal.
it is very humid in chille and everything rusts. i just did not ever think that a injector can rust to the point of separation but its possible!
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Re: Using the Bosch injectors
You know, you have been breaking my chops long enough. First of all we gladly refunded that guys money for those injectors, and you know what, you can call that rust, but when we received them it was dirt. These injectors are USED they are not perfect. Funny, none of my customers cars ever blew up!!!!!!!!!
Sorry, i don't mean to bust your chops, just trying to protect any unaware people. Messing with fuel systems is dangerous and a lot of guys are not professional mechanic like me, so it only takes one to disaster !
Take care,thanks
#21
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Re: Using the Bosch injectors
I am so happy that you posted this picture, before you go bad mouthing people and their companies you'd better damn well know what you are talking about!!!!!!!!!!! Where do they have that wide SPACER?? Exactly where the second oring is supposed to go onto the groove above the first oring! That is what gives it the elevation, the lower oring is what goes into the intake---has nothing to do with the height!!!!!!! Remove everything from the bottom of this injector and you will see.. presto... it is a regular bosch design lll injector that is made to look like the one and only bosch that will fit your engines. So give me a break, and once and for all BACK OFF!
People should buy from who ever they want, but it has to be for the honest and proper reason.
People should buy from who ever they want, but it has to be for the honest and proper reason.
#22
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Re: Using the Bosch injectors
I think you've more than made your point, such that it is. If you want injectors to look brand new, then buy new they're only 3 times as expensive..... BTW, you're the only one I can recall that has burned down two vehicles. Given that, you might reconsider your declared expertise in this area.
The second o-ring is not a safety issue IMO, it's just a spacer to help hold the injector higher into the fuel rail. Pushing the injector deeper into the intake is not going to ensure a better seal, especially fuel wise since the bottom is just a vacuum seal.
The second o-ring is not a safety issue IMO, it's just a spacer to help hold the injector higher into the fuel rail. Pushing the injector deeper into the intake is not going to ensure a better seal, especially fuel wise since the bottom is just a vacuum seal.
#23
Sponsor
Re: Using the Bosch injectors
Beware !!!
I Don't want to chime here for nothing,im very picky when injector installation procedures are at play here,i don't play with FIRE,period.-
I have to say it but ,Southbay,last month you were selling RUSTED injectors.-
Now what would happen if Trinamo install the injectors he posted above and add
an extra oring ? That will leak as hell and he will probably burn the car.-
Trinamo,sorry to chime like this.-
Southbay,i have to get into,because i have had problems with injectors on my jeeps
and when they catch fire its no fun,believe me its no fun and you want to do whatever
it takes to put the fire down.-
This is no game,why you keep giving WRONG installation instructions ?
I Swear i cannot believe you are telling this guy to install additional orings
on those injectors !
Remember THIS THREAD ?
Remember this product you were selling ?
![](http://img139.imageshack.us/img139/4724/injectors20in20fuel20ra.jpg)
Sorry,but are you a pyromaniac ?
I Don't want to chime here for nothing,im very picky when injector installation procedures are at play here,i don't play with FIRE,period.-
I have to say it but ,Southbay,last month you were selling RUSTED injectors.-
Now what would happen if Trinamo install the injectors he posted above and add
an extra oring ? That will leak as hell and he will probably burn the car.-
Trinamo,sorry to chime like this.-
Southbay,i have to get into,because i have had problems with injectors on my jeeps
and when they catch fire its no fun,believe me its no fun and you want to do whatever
it takes to put the fire down.-
This is no game,why you keep giving WRONG installation instructions ?
I Swear i cannot believe you are telling this guy to install additional orings
on those injectors !
Remember THIS THREAD ?
Remember this product you were selling ?
![](http://img139.imageshack.us/img139/4724/injectors20in20fuel20ra.jpg)
Sorry,but are you a pyromaniac ?
By the way, the picture of the same injectors on this thread are not our injectors, take a good look at them, I am sure that if you took a close up picture of them you would probably find plenty wrong with them also.
#24
Sponsor
Re: Using the Bosch injectors
You know what that is fine, but what could ever make you think that we would sell something to someone that could endanger their lives????? Did you ever think that we have a reputation to uphold? We are here to help, why do you think that we pay to be sponsors of this forum, so we have the ability to sell crap? Or offer advice that is going to hurt someone?Don't be so quick to trash peoples reputations. Now, , can we please move on?
#25
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Re: Using the Bosch injectors
![Smilie](https://www.thirdgen.org/forums/images/smilies/smile.gif)
![Smilie](https://www.thirdgen.org/forums/images/smilies/smile.gif)
#26
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Re: Using the Bosch injectors
Ok it was dirt ?
Then i guess the dirt ate away the plastic top ?? lol !
What i think its the same thing happened on my Jeep,the rust build up and pushed the plastic,
you can clearly see its ate up !!!
Im not trying to put you down at all,you are the rebuilder and things like that should not go out
if you have any quality control !
Used or not they should look remaned,not looking like that !
Please be careful in the future,im sure you will !
Im done on this too,again im just trying to help and my motivation is not to put your company down
i've been thru many things and i've seen so many things on this cars that i'd rather beware than sorry
You are probably nice people,im just trying to avoid mistakes and possible disasters .-
Sammy
Then i guess the dirt ate away the plastic top ?? lol !
What i think its the same thing happened on my Jeep,the rust build up and pushed the plastic,
you can clearly see its ate up !!!
Im not trying to put you down at all,you are the rebuilder and things like that should not go out
if you have any quality control !
Used or not they should look remaned,not looking like that !
Please be careful in the future,im sure you will !
Im done on this too,again im just trying to help and my motivation is not to put your company down
i've been thru many things and i've seen so many things on this cars that i'd rather beware than sorry
You are probably nice people,im just trying to avoid mistakes and possible disasters .-
Sammy
#27
Re: Using the Bosch injectors
Thanks for the chime in but this thread is now OFF TOPIC!!!!!!
My injectors have no rust/chips period! Back to installation! PLEASE!!!!!
Add o-ring then they fit??????
My injectors have no rust/chips period! Back to installation! PLEASE!!!!!
Add o-ring then they fit??????
#28
Sponsor
Re: Using the Bosch injectors
In closing, when these injectors are yanked out of cars with wrenches, how do you think the plastic or metal bodies are supposed to look???
Nothing in this world is perfect. You just need to do the very best that you can, and make sure that you provide good customer service, and rectify a situation in the proper manner.
Nothing in this world is perfect. You just need to do the very best that you can, and make sure that you provide good customer service, and rectify a situation in the proper manner.
#29
Sponsor
Re: Using the Bosch injectors
Yes, they will. If you would like to contact us, just give us a call at 516-492-6504, we will do what we can to help you.
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Re: Using the Bosch injectors
Ican be called an expert mechanic and the reason the jeep burned was that the fuel leaked from case separation it was not from my lack of experience.
it is very humid in chille and everything rusts. i just did not ever think that a injector can rust to the point of separation but its possible!
it is very humid in chille and everything rusts. i just did not ever think that a injector can rust to the point of separation but its possible!
Houston is just as humid as anything you could have, but it's not salt air. Do you live close to sea water? If so, then you already know to expect everything to rust. IMO, the specs visible in the greatly magnified photos wouldn't affect the o-rings ability to seal. I doubt they can be readily seen with the naked eye.
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Re: Using the Bosch injectors
....Nevermind. Just saw it had already been mentioned that the pic above are Bosch II's.
Last edited by Reid Fleming; 06-12-2009 at 01:53 PM.
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Re: Using the Bosch injectors
You bought the wrong Bosch injectors. Send them back and get the Bosch III's from FIC (Fuel Injector Connection). The ones that they make are flow balanced and are longer (same size as stock). They're the only people I know that make the injectors longer than a regular Bosch injector would be.
http://fuelinjectorconnection.com/shop/
http://fuelinjectorconnection.com/shop/
I already planned to change my ECU controlled cooling fan turn on and off thresholds so I may try changing some fueling calibrations to enrichen the open loop fueling and to get the BLM below the maximum value.
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Re: Using the Bosch injectors
I bought the Bosch Design III injectors from Jon at F.I.C. The injectors have a third o-ring in them that makes them almost as long as the original Multec injectors. The injectors he sends for the LB9 (5.0 Liter) are from a Ford Contour. They are an off-white color rather than the more common yellow Bosch injectors. The picture for the LB9 injectors at his website is actually for different, higher flow rated injectors for the L98 engine. He says Ford Contour injectors have the correct lb/hr rating, 19, and spray pattern for the LB9. He said the 22 lb/hr injectors would work but would run rich in open loop mode and would cause starting problems at very cold temperatures due to overly rich mixture. After installing the injectors and replacing a "lazy" oxygen sensor so it will stay in close loop mode, I am afraid the injectors have a lower flow rate than the original Multecs. The car often will not start on the first, short crank. I think the open loop fuel pulse width is about 0.2 msec shorter than the close loop pulse width. The BLM is maxed out at 160. I am still waiting for an e-mail reply from Jon. I will probably try to call him after I drive the car now that I have replaced the oxygen sensor with another AC Delco stamped single wire sensor (not a Bosch sensor repackaged in an AC Delco box).
I already planned to change my ECU controlled cooling fan turn on and off thresholds so I may try changing some fueling calibrations to enrichen the open loop fueling and to get the BLM below the maximum value.
I already planned to change my ECU controlled cooling fan turn on and off thresholds so I may try changing some fueling calibrations to enrichen the open loop fueling and to get the BLM below the maximum value.
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Re: Using the Bosch injectors
You're right that it could be a vacuum leak or some other problem. I did check for vacuum leaks in the area I worked when pulling the plenum but I did not check elsewhere such as at the vapor canister. I will go over the engine again looking for vacuum leaks. The engine idles as well as it ever has so I did not think I have a vacuum leak. The warm desired idle is 750 RPM and the actually is roughly 740 to 800 RPM. I assume this is normal. The IAC counts at this RPM range are 5 to 20. The counts do not change any once it is close to 750. At this point I only noticed that the spark advance changes slightly. What else can I do to rule out a vacuum leak? I can post MAP and other values one a reconnect my scan tool and take notes.
I also need to retest the fuel pressure at the fuel rail. I have not tested the pressure on the car for over 8 years--the previous time I replaced 4 Multec injectors with 4 new Multecs.
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Re: Using the Bosch injectors
I did not intend to get off the topic of the thread. I think the Bosch injectors are great and would not buy them from anyone but F.I.C. but one also needs to make sure there is nothing else is wrong with the engine. I had a bad O2 sensor that I think I have resolved that caused the engine to jump in and out of closed loop mode. With the new O2 sensor the engine stayed in closed loop mode for over 30 minutes while parked and for over 25 minutes while I drove it 12 miles this morning. The engine feels great now when accelerating. I only drove it 12 miles with the Bosch injectors and only hit a max of 50% throttle so I have more testing I need to complete. I don't feel the BLM problem while driving but I know there is something more wrong that I need to resolve.
You're right that it could be a vacuum leak or some other problem. I did check for vacuum leaks in the area I worked when pulling the plenum but I did not check elsewhere such as at the vapor canister. I will go over the engine again looking for vacuum leaks. The engine idles as well as it ever has so I did not think I have a vacuum leak. The warm desired idle is 750 RPM and the actually is roughly 740 to 800 RPM. I assume this is normal. The IAC counts at this RPM range are 5 to 20. The counts do not change any once it is close to 750. At this point I only noticed that the spark advance changes slightly. What else can I do to rule out a vacuum leak? I can post MAP and other values one a reconnect my scan tool and take notes.
I also need to retest the fuel pressure at the fuel rail. I have not tested the pressure on the car for over 8 years--the previous time I replaced 4 Multec injectors with 4 new Multecs.
You're right that it could be a vacuum leak or some other problem. I did check for vacuum leaks in the area I worked when pulling the plenum but I did not check elsewhere such as at the vapor canister. I will go over the engine again looking for vacuum leaks. The engine idles as well as it ever has so I did not think I have a vacuum leak. The warm desired idle is 750 RPM and the actually is roughly 740 to 800 RPM. I assume this is normal. The IAC counts at this RPM range are 5 to 20. The counts do not change any once it is close to 750. At this point I only noticed that the spark advance changes slightly. What else can I do to rule out a vacuum leak? I can post MAP and other values one a reconnect my scan tool and take notes.
I also need to retest the fuel pressure at the fuel rail. I have not tested the pressure on the car for over 8 years--the previous time I replaced 4 Multec injectors with 4 new Multecs.
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Re: Using the Bosch injectors
thinking about it. if you test for vac leak with propane and don't find one it does not mean you don't have one internally at the bottom of the intake into the crank case.. its hard to find those but they happen. It sound like its idleing smooth with those iac counts so you might want to look at fuel pressure.. That could be a reason for the BLM to be high also. Injectors flow less at lower pressure and the computer will only adjust so much because the BLM table i think maxes out at 160,, Look for fuel pressure problem over vac leak as that idle is very smooth.
The fuel pressure should be between 40.5 and 47 PSI or 41 to 47 PSI according to GM shop manuals. Some say it should be 42 to 47. According to Jon at F.I.C., it should be 42 at idle and 47 at WOT. I think the injectors are working properly and that there is a problem elsewhere so I checked the fuel pressure. I did not have time today to do WOT with gauge taped to windshield and a passenger to read the gauge so I pulled the vacuum line to simulate WOT.
My car, a 1990 LB9 (305), has not been modified. The only fueling components replaced have been injectors, gas cap, and fuel filter. I probably should replace the fuel filter again based on age and not mileage. The car has 43K miles on it. I should probably remove the locking gas cap and re-install the original or leave the cap off while testing in my garage.
Here are my fuel pressures:
At key on while pump is on: 42 PSI.
At key on while pump is off before pressure slowly bleeds off: 40 PSI
Engine at idle: 38 PSI
Engine off idle (probably 1500 to 2000 RPM): jumps to 41 during tip-in and drops quickly to 31 PSI
Engine at idle with vacuum hose removed to simulate WOT with no vacuum: jitters between 42.5 and 43.5
Engine off idle (probably 1500 to 2000 RPM) with vacuum hose removed: 43 PSI steady
At ignition on while pump is on with return hose clamped off with Vice Grips: 64 PSI
Based on the above, I think my pump is okay since it reads 64 PSI with return hose clamped shut. Don't run the engine with the return hose clamped off.
I am not sure why it reads 31 PSI above in the one situation when it reads 43 with the vacuum hose removed. I may still do a WOT test. I may need to buy the 100-102 fuel regulator from TPIS.com. I hope I don’t need to drop the tank and install a new fuel pump.
For the original poster, I suggest you check your fuel pressure and BLMs before you replace your injectors. If the pressure regulator needs to be replaced then you want to do it while changing the injectors so you do not have to remove the plenum twice.
Last edited by Brighton; 11-18-2009 at 07:23 PM.
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Re: Using the Bosch injectors
The IAC has gone to 0 counts a few times too but actual idle speed is still very close to desired speed.
The fuel pressure should be between 40.5 and 47 PSI or 41 to 47 PSI according to GM shop manuals. Some say it should be 42 to 47. According to Jon at F.I.C., it should be 42 at idle and 47 at WOT. I think the injectors are working properly and that there is a problem elsewhere so I checked the fuel pressure. I did not have time today to do WOT with gauge taped to windshield and a passenger to read the gauge so I pulled the vacuum line to simulate WOT.
My car, a 1990 LB9 (305), has not been modified. The only fueling components replaced have been injectors, gas cap, and fuel filter. I probably should replace the fuel filter again based on age and not mileage. The car has 43K miles on it. I should probably remove the locking gas cap and re-install the original or leave the cap off while testing in my garage.
Here are my fuel pressures:
At key on while pump is on: 42 PSI.
At key on while pump is off before pressure slowly bleeds off: 40 PSI
Engine at idle: 38 PSI
Engine off idle (probably 1500 to 2000 RPM): jumps to 41 during tip-in and drops quickly to 31 PSI
Engine at idle with vacuum hose removed to simulate WOT with no vacuum: jitters between 42.5 and 43.5
Engine off idle (probably 1500 to 2000 RPM) with vacuum hose removed: 43 PSI steady
At ignition on while pump is on with return hose clamped off with Vice Grips: 64 PSI
Based on the above, I think my pump is okay since it reads 64 PSI with return hose clamped shut. Don't run the engine with the return hose clamped off.
I am not sure why it reads 31 PSI above in the one situation when it reads 43 with the vacuum hose removed. I may still do a WOT test. I may need to buy the 100-102 fuel regulator from TPIS.com. I hope I don’t need to drop the tank and install a new fuel pump.
For the original poster, I suggest you check your fuel pressure and BLMs before you replace your injectors. If the pressure regulator needs to be replaced then you want to do it while changing the injectors so you do not have to remove the plenum twice.
The fuel pressure should be between 40.5 and 47 PSI or 41 to 47 PSI according to GM shop manuals. Some say it should be 42 to 47. According to Jon at F.I.C., it should be 42 at idle and 47 at WOT. I think the injectors are working properly and that there is a problem elsewhere so I checked the fuel pressure. I did not have time today to do WOT with gauge taped to windshield and a passenger to read the gauge so I pulled the vacuum line to simulate WOT.
My car, a 1990 LB9 (305), has not been modified. The only fueling components replaced have been injectors, gas cap, and fuel filter. I probably should replace the fuel filter again based on age and not mileage. The car has 43K miles on it. I should probably remove the locking gas cap and re-install the original or leave the cap off while testing in my garage.
Here are my fuel pressures:
At key on while pump is on: 42 PSI.
At key on while pump is off before pressure slowly bleeds off: 40 PSI
Engine at idle: 38 PSI
Engine off idle (probably 1500 to 2000 RPM): jumps to 41 during tip-in and drops quickly to 31 PSI
Engine at idle with vacuum hose removed to simulate WOT with no vacuum: jitters between 42.5 and 43.5
Engine off idle (probably 1500 to 2000 RPM) with vacuum hose removed: 43 PSI steady
At ignition on while pump is on with return hose clamped off with Vice Grips: 64 PSI
Based on the above, I think my pump is okay since it reads 64 PSI with return hose clamped shut. Don't run the engine with the return hose clamped off.
I am not sure why it reads 31 PSI above in the one situation when it reads 43 with the vacuum hose removed. I may still do a WOT test. I may need to buy the 100-102 fuel regulator from TPIS.com. I hope I don’t need to drop the tank and install a new fuel pump.
For the original poster, I suggest you check your fuel pressure and BLMs before you replace your injectors. If the pressure regulator needs to be replaced then you want to do it while changing the injectors so you do not have to remove the plenum twice.
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Re: Using the Bosch injectors
Could explain specifically what numbers you don’t like and what you would expect them to be with an original FPR.
I am not saying you are wrong about the numbers being bad but the following discussions have posters who think my 38 PSI and 42 or 43 PSI numbers are okay. Maybe they too have original FPRs that are should be replaced.
https://www.thirdgen.org/forums/tpi/424258-new-tpi-fuel-pump.html
https://www.thirdgen.org/forums/tpi/530632-how-much-replace-fuel.html
https://www.thirdgen.org/forums/tpi/472071-looking-input-89-305-a.html
https://www.thirdgen.org/forums/tpi/543780-new-tpi-some-concerns.html
https://www.thirdgen.org/forums/tech-general-engine/538856-weak-fuel-pump.html
Last edited by Brighton; 11-18-2009 at 09:02 PM.
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Re: Using the Bosch injectors
Thanks for the reply.
Could explain specifically what numbers you don’t like and what you would expect them to be with an original FPR.
I am not saying you are wrong about the numbers being bad but the following discussions have posters who think my 38 PSI and 42 or 43 PSI numbers are okay. Maybe they too have original FPRs that are should be replaced.
https://www.thirdgen.org/forums/tpi/424258-new-tpi-fuel-pump.html
https://www.thirdgen.org/forums/tpi/530632-how-much-replace-fuel.html
https://www.thirdgen.org/forums/tpi/472071-looking-input-89-305-a.html
https://www.thirdgen.org/forums/tpi/543780-new-tpi-some-concerns.html
https://www.thirdgen.org/forums/tech-general-engine/538856-weak-fuel-pump.html
Could explain specifically what numbers you don’t like and what you would expect them to be with an original FPR.
I am not saying you are wrong about the numbers being bad but the following discussions have posters who think my 38 PSI and 42 or 43 PSI numbers are okay. Maybe they too have original FPRs that are should be replaced.
https://www.thirdgen.org/forums/tpi/424258-new-tpi-fuel-pump.html
https://www.thirdgen.org/forums/tpi/530632-how-much-replace-fuel.html
https://www.thirdgen.org/forums/tpi/472071-looking-input-89-305-a.html
https://www.thirdgen.org/forums/tpi/543780-new-tpi-some-concerns.html
https://www.thirdgen.org/forums/tech-general-engine/538856-weak-fuel-pump.html
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Re: Using the Bosch injectors
well not to sound like a no it all, but i have been in this business for almost 40 yrs. My dad, a service station owner was a excellent mechanic, my two brothers are mechanics (sounds like my cousin vinny) I have replaced intakes, fuel rails, injectors in a few hundred of these. I always scan the vehicles when finished and always check fuel pressures. So with that being said, when I have low fuel pressure I have high BLM. Most of these posters could not tell you what their BLM's are nor do they care. By the way I bet your car is running great, Isn't it? But you see a high BLM and you continue to find the cure. That is what I would do also. But, if you did not know how to scan you would think its fine. A high BLM does not mean its lean running. It only means that the computer is adding fuel to get to a stoichiometric ratio. This is something most don't know about. You asked by posting, I am answering, I will try to help you or anyone if I can, but to go head to head with others that say 38 is a good enough fuel pressure on a 3 bar regulator is rediculous. I think the numbers are more in line with mine in the Factory service manual. That should be your guide. Not forum wiz kids. All I can tell you is that fuel pressure should never go to 31 as stated in your previous post. If I were you I would double check the fuel pressure and if it is a few points low either enjoy the car or get it right and raise the pressure..
Yes, you are correct--the car runs great now that I have the Bosch injectors in it from F.I.C. If I did not have a scan tool I may not have noticed the defective O2 sensor I recently replaced that was preventing it from staying in closed loop mode. The BLMs and O2 sensor were probably bad when I brought the car back to life with a new distributor this spring after it had sat in my garage for years. I now wish I had connected a scan tool back in the spring.
Another thing not discussed yet is whether or not the pressure gauge is accurate. I used a pressure gauge I probably bought from AutoZone back in the late 90's when the first injectors shorted out and have not used the gauge until now. There is no name on it. Tonight I used a Actron CP9920A rent-a-tool from AutoZone.
The numbers tonight were:
46 PSI with hose off.
36 PSI with hose on.
The BLM cell at idle during testing would always jump straight to 160 when at 36 PSI. It takes 5 minutes or longer to get to 160 with 46 PSI after resetting the integrator and BLM cells to 128. The idle BLM cell moved quickly to 152 and then took many minutes to get to 160. The fast fuel trim (integrator) is about 127 to 132 with a 46 PSI and 135 to 138 with 36 PSI when the BLM has stabilized or max’ed out. The injector pulse width is 1.8 to 1.9 msec with 46 PSI and 2.0 to 2.1 with a PSI of 36. The higher fuel pressure with the hose off does make a noticeable difference in the integrator and fuel pulse width.
So I agree that it looks like the higher pressure that a new AFPR will provide some help with the BLM problem but I don't see how it will eliminate the high BLM issue given that a pressure of 46 with the hose off still maxes out the BLM. I plan to order a new TPIS AFPR but expect that I will still have abnormally high BLM values (at or near 160) unless I run the new AFPR at more than 46 PSI at idle with the hose on and at 50 at WOT with the hose on.
Last edited by Brighton; 11-19-2009 at 12:07 AM.
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Re: Using the Bosch injectors
i think the first pressure gage you used may have been right, or closer to right than the second one was. you may want to swing by another place and try a different gage.
there is a pretty wide spread on the recommended fuel pressure, 40.5~47 PSI key on engine off. with a 3~10 PSI drop with vacuum. i could see it dropping to 31 under decel if the KOEO pressure is in the low 40 PSI range.
the TBI systems have specs of 9~13 PSI, but very few TBI systems will run ok at 10 PSI, much less 9 PSI. i only recall working on one that was around 9.5 PSI that didn't have a huge bog at WOT, but it was coding lean which is what it was in for.
TBI really needs to be at least 12 PSI to run right and not have the fuel trims pushed way up.
the TPI systems are the same way. when they are at the low end of the specs they run lean. usually not enough to kick a lean code, but still have high fuel trims.
if you are at 43 PSI without vacuum, even though its within specs i would think it would still be on the lean side.
there is a pretty wide spread on the recommended fuel pressure, 40.5~47 PSI key on engine off. with a 3~10 PSI drop with vacuum. i could see it dropping to 31 under decel if the KOEO pressure is in the low 40 PSI range.
the TBI systems have specs of 9~13 PSI, but very few TBI systems will run ok at 10 PSI, much less 9 PSI. i only recall working on one that was around 9.5 PSI that didn't have a huge bog at WOT, but it was coding lean which is what it was in for.
TBI really needs to be at least 12 PSI to run right and not have the fuel trims pushed way up.
the TPI systems are the same way. when they are at the low end of the specs they run lean. usually not enough to kick a lean code, but still have high fuel trims.
if you are at 43 PSI without vacuum, even though its within specs i would think it would still be on the lean side.
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Re: Using the Bosch injectors
No code has ever set when the fuel injectors shorted out or when the oxygen sensor failed such that the ECM would jump repeatedly in and out of closed loop fuel mode. So I know that I need to use a scanner to see if it is running properly. I think anyone with one of these old cars should invest in some scan tool and an Ohm meter if they want to make sure the engine is operating properly because the OBDI diagnostics will not catch some of the common problems that occur with these engines. No one should say anything negative about the Bosch Design III injectors until they use a scan tool to make sure there is nothing else wrong.
I ordered an AFPR from TPIS that I should receive on Monday. I'll reply with results.
I also bought an AC Delco made in USA fuel filter that I will install by this weekend. I should have replaced the current one shortly after bringing the car back to life this spring after it sat in my garage for years due to a bad pole piece on the distributor. I bought it at Murrays/O'Reilys. The also sold a $7 MicroGard possibly made by Purolater and a $15 Fram filter. Other options where a $10 Champion Labs filter from AutoZone.
Last edited by Brighton; 11-19-2009 at 10:34 AM.
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Re: Using the Bosch injectors
The only codes my car have ever set are one for loss of VSS when the sensor it failed completely and an open on the coolant sensor used by the ECM.
No code has ever set when the fuel injectors shorted out or when the oxygen sensor failed such that the ECM would jump repeatedly in and out of closed loop fuel mode. So I know that I need to use a scanner to see if it is running properly. I think anyone with one of these old cars should invest in some scan tool and an Ohm meter if they want to make sure the engine is operating properly because the OBDI diagnostics will not catch some of the common problems that occur with these engines. No one should say anything negative about the Bosch Design III injectors until they use a scan tool to make sure there is nothing else wrong.
I ordered an AFPR from TPIS that I should receive on Monday. I'll reply with results.
I also bought an AC Delco made in USA fuel filter that I will install by this weekend. I should have replaced the current one shortly after bringing the car back to life this spring after it sat in my garage for years due to a bad pole piece on the distributor. I bought it at Murrays/O'Reilys. The also sold a $7 MicroGard possibly made by Purolater and a $15 Fram filter. Other options where a $10 Champion Labs filter from AutoZone.
No code has ever set when the fuel injectors shorted out or when the oxygen sensor failed such that the ECM would jump repeatedly in and out of closed loop fuel mode. So I know that I need to use a scanner to see if it is running properly. I think anyone with one of these old cars should invest in some scan tool and an Ohm meter if they want to make sure the engine is operating properly because the OBDI diagnostics will not catch some of the common problems that occur with these engines. No one should say anything negative about the Bosch Design III injectors until they use a scan tool to make sure there is nothing else wrong.
I ordered an AFPR from TPIS that I should receive on Monday. I'll reply with results.
I also bought an AC Delco made in USA fuel filter that I will install by this weekend. I should have replaced the current one shortly after bringing the car back to life this spring after it sat in my garage for years due to a bad pole piece on the distributor. I bought it at Murrays/O'Reilys. The also sold a $7 MicroGard possibly made by Purolater and a $15 Fram filter. Other options where a $10 Champion Labs filter from AutoZone.
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Re: Using the Bosch injectors
The Bosch Design III injectors from F.I.C. fit great with the extra o-ring they pre-install. They are installed into the engine before the fuel rail. The Design III's do not use the clips found in the Multec injectors. The Bosch insert so easily into the intake that I did not think I had them fully inserted. One needs to be sure they are lined up properly with the opening in the fuel rail before pushing the rail down on them. Then one needs to be careful to get the fuel rail down far enough to touch the rail mount positions. The key is to take ones time and double check the alignments and do not twist injectors which could damage o-rings. This part of the job was relatively easily. Much easier than dealing with the lower bolts on the runners. One needs to make sure they have an assortment of socket extensions. I bought a 3/8 to 1/4 adapter so I could use my 1/4 socket set with my Torx socket. The 1/4 wrench is easier to use with some of the lower bolts. The car still has A.I.R. so it got in the way of one or two lower runner bolts on the passenger side. I pressured the fuel rail before re-installing the plenum to make sure there were no fuel leaks. So far I think the 8 Bosch Design III injectors from F.I.C. for $170 or for $200 with all the gaskets and fuel rail o-rings is a great deal compared to what others charge per injector. Jon at F.I.C. has provided excellent customer service.
I thought the following from TPIS was interesting. They claim 40 to 42 PSI is the stock pressure for my car with the hose disconnected. My readings were actually higher in this case. I'll assume I should try 47 to 50 PSI with their regulator installed and the hose off.
http://www.tpis.com/instructions/Fue...structions.doc
8.The Adjustable Fuel Pressure Regulator should be adjusted with motor running and regulator vacuum line disconnected. At idle, turn regulator adjusting nut clockwise to increase fuel pressure. Best setting should be 47 to 48 psi. (stock pressure is 36 to 39 psi for 85-87, and 40 to 42 psi for 88 and later)
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Re: Using the Bosch injectors
the multecs were junk when they were new. they don't need E10 to have
problems. i've replaced many of them back when electronic fuel injection was a new thing.
i've installed some of the modded bosch 3s and they fit perfectly fine.
although i do the opposite of the directions, i install them in the rails first and then push them down into the intake after i bolt the rail down.
the owner of the last car i did said it has been years since the car ran as smooth or as good as it does now.
Brighton, for a good scan tool, i recommend a laptop with TunerPro.
i've used a number of the aftermarket scanners and none of them come close to matching TunerPro with the right def files. also you get a much longer data recording with TunerPro.
problems. i've replaced many of them back when electronic fuel injection was a new thing.
i've installed some of the modded bosch 3s and they fit perfectly fine.
although i do the opposite of the directions, i install them in the rails first and then push them down into the intake after i bolt the rail down.
the owner of the last car i did said it has been years since the car ran as smooth or as good as it does now.
Brighton, for a good scan tool, i recommend a laptop with TunerPro.
i've used a number of the aftermarket scanners and none of them come close to matching TunerPro with the right def files. also you get a much longer data recording with TunerPro.
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Re: Using the Bosch injectors
Set the fuel pressure to stock, unless you plan on adjusting the injector constant to match your new flow rate... since you have swapped to the Bosch III you might want to find the specs on them and see what they really flow, set your fuel pressure to around what stock was and adjust the injector constant in the ecm to the right number.
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Re: Using the Bosch injectors
I'd forget about that nonsense from TPIS. That stock pressure data is wrong as well.
Set the fuel pressure to stock, unless you plan on adjusting the injector constant to match your new flow rate... since you have swapped to the Bosch III you might want to find the specs on them and see what they really flow, set your fuel pressure to around what stock was and adjust the injector constant in the ecm to the right number.
Set the fuel pressure to stock, unless you plan on adjusting the injector constant to match your new flow rate... since you have swapped to the Bosch III you might want to find the specs on them and see what they really flow, set your fuel pressure to around what stock was and adjust the injector constant in the ecm to the right number.
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Re: Using the Bosch injectors
I have TunePro and def file for my vehicle. I don't have the proper cable yet so I borrowed a different scan tool from someone.
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Re: Using the Bosch injectors
I am currently using a set of Bosch III's that I bought fom south bay. I have had no problems with the injectors. The injectors that I purchased have the spacer installed on them. Therefore there are no more need for the extra o-ring. The injectors don't leak and they fit into the fuel rail as well as the intake with no problems. The price as wella sthe service was great. After all, you have a three year warranty, so what is there to loose!
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