Keoman

iTrader: (3)

I have been working on this for three days now, used up a whole tank of gas and still cannot get BLMs to stay around 128 under about 18 g/sec.

Right as soon as I get good idle readings sitting in the driveway in closed loop, take it for a spin around the block, come back park it in the driveway again and its around 121. Adjust it and take it out, come back and its still off. Time and time again. Started with a new APYP bin twice now.

also getting a bad stutter under low load situation (around 50-80 LV8)

Car runs fine otherwise. Pulled the plugs and they are a light shade of tan, look great to me.

TPS, base timing, injector constant, all checked twice and fine. Timing table is from APYN3496 (my stock chip). Fuel pressure @ 40psi

I don't know what to do, what am I missing? Haven't driven my car on the road for over a year and a half now ever since i started this vortec project and right now I'm really regretting ever doing it.

Orr89RocZ

iTrader: (20)

To behonest you will be chasing your tail tryin to get blm perfect 128 at idle or low flow situations. 121 isnt bad at all. The amount of change needed to bring that around to 128 is tiny.

Plus take a look at the o2 constants. Low flow regions typically have a different target air fuel ratio to compensate for egr/air function. 550mv instead of 450-470. There could be fueling changes based on coolant temps or slightly battery voltage fluxuations that may also shift your low flow blm values.

Keoman

iTrader: (3)

Okay, I can live with 121 BLM, but what about the stuttering?? Surely that is not normal and has some root cause?

What do I need to do to diagnose what is causing this?

RBob

iTrader: (1)

The stuttering could be from fueling or spark advance issues. Too much SA can causes this as well as being on the lean side fuel wise. Data log and try to stay in the stutter as long as possible.

Look at the log, what does the INT & O2 do, how much SA is there.

RBob.

Orr89RocZ

iTrader: (20)

Yeah gotta look at everything during that time period it stutters. Fuel and spark mainly. Might be a lean spot

Keoman

iTrader: (3)

Took multiple logs of the stutter.

It is most violent from 55-65 LV8 (around 800-1200 rpms)
BLM's never really move from 120 the whole time.
MAF readings 12 g/sec
Spark advance between 24-26* BTDC
INT varies quickly between 122-131

I'm not sure what I need to do now.
Any other readings I should note?

In pic:
Top = O2 and INT
Bottom = Temp, LV8 and TPS

RBob

iTrader: (1)

The proportional gains are too high. The INT is trying to keep the O2 sensor swing in check.

RBob.

Keoman

iTrader: (3)

How do I change the proportional gains in $6E to fix this?

EDIT
After lots of searching and reading, seems this is what I am after, changing the "o2 constants" as Orr put it.

https://www.thirdgen.org/forums/diy-...ome-those.html
https://www.thirdgen.org/forums/diy-...d-voltage.html

Is this correct?

RBob

iTrader: (1)

Found some good threads there, note that the 747Fueling write up is also here on TGO. A link is in the Tuning Guide Book sticky. Be sure to read it.

I found that there is only one table for proportional gain:

; PROPORTIONAL STEP DURATION Vs. Error

@ $4A1

Reduce the values in that table to reduce the prop gains. There are also duration tables that can be tweaked.

RBob.

Keoman

iTrader: (3)

Alright, looked up Prop Step Duration (the XDF that tunerpro comes with is very limited, downloaded rhuarc31's expanded xdf)
It shows three tables. The two tables you mentioned, Proportional Step Duration Vs. Error and Proportional Step Size Vs Error. Also lists Proportional Step Duration Offset Vs RPM (shown in attached photo)

I dont get what the error counts are referenced to. Error counts of what? O2 values being outside the R/L tables? How often are these counts taken and where are they shown in the data log?

In your article, you mention this,
I wouldn't consider my setup a "Highly Tuned Engine" as you put it, would I be safe in reducing these values 25%? Do I reduce every single value in the entire table by the same amount or is there somewhere I can see how many error counts I am getting to reduce values in sections of the table?

Keoman

iTrader: (3)

Decreased the values by 25%, then 35% with no noticeable change. Should I go more?

25%


35%

Keoman

iTrader: (3)

Any Ideas?

Orr89RocZ

iTrader: (20)

Whats timing curve look like there?

Keoman

iTrader: (3)

This is the situation it is most violent in:

It is most violent from 55-65 LV8 (around 800-1200 rpms)
BLM's never really move from 120 the whole time.
MAF readings 12 g/sec
Spark advance between 24-26* BTDC
INT varies quickly between 122-131

This is my timing table as it sits right now.

Note* I have adjusted timing from down near 14* all the way to 24* as you can see under 80 LV8. These changes had no effect on how the car acted.

RBob

iTrader: (1)

What size injectors are in the engine?

RBob.

Keoman

iTrader: (3)

They are 22# south bay TPI replacment injectors.
http://www.southbayfuelinjectors.com...rs/?fullSite=1

Stock L98 bottom end
906 vortec heads
FIRST TPI intake
Cam is 218/224 duration@.050
.502/.509 lift
112* LSA
Comp 1.52 roller lifters

RBob

iTrader: (1)

This may help, double check the Bosch part # listed. It is also molded into the injector.

Injector Data Sheet: M-9593-AA302, 24 #/hr Bosch 3, 280-155-931

Fuel Pressure: 46 psi

Minimum PW @ 46 psi: 508 usec

Offset Compensation versus Battery Voltage:
6.4 Volts: 2001 usec
8.0 Volts: 1385 usec
9.6 Volts: 1042 usec
11.2 Volts: 819 usec
12.8 Volts: 664 usec
14.4 Volts: 531 usec
15.0 Volts: 491 usec* extrapolate out to higher voltages

Flow rate: 26.1 #/hr

Zero this table:

Short PW Compensation versus Pulse Width:
0.015 msec: -213 usec
0.244 msec: -172 usec
0.488 msec: -129 usec
0.732 msec: -86 usec
0.976 msec: -43 usec
1.220 msec: -0 usec
1.460 msec: 0 usec
1.708 msec: 0 usec
1.950 msec: 0 usec
2.197 msec: 0 usec
2.440 msec: 0 usec
2.685 msec: 0 usec
2.929 msec: 0 usec
3.170 msec: 0 usec
3.410 msec: 0 usec
3.660 msec: 0 usec
3.900 msec: 0 usec

RBob.

Keoman

iTrader: (3)

The part number you listed does not match what is on my injectors.
280-155-700 is the number stamped on my injectors. These two websites put them around 19#/hr
http://clean.injectorrx.com/bosch-fuel-injectors/
http://www.fuelinjector.citymaker.co...low_Rates.html

Is this the problem?

Orr89RocZ

iTrader: (20)

Try adding more fuel in that region of 12-15 g/sec and see what happens

It shouldnt have issues with only 24-26 timing at that point

RBob

iTrader: (1)

It may be a problem, not sure. The Stan Weiss list of injectors has it at 18.25#/hr at 3-bar (43.5 psi).

The above injector compensation values are not for this injector.

RBob.

Keoman

iTrader: (3)

Going to have to have southbay ship me the correct injectors and tear everything apart again. Oh Joy...

Changing the injector constants to 19# hr did not do one thing to help this stuttering.

I added 20% fuel between 6 and 13 gm/s, just made it run at 108 blm and int was still jumping back and forth about 8 numbers. Still stuttering also.

Orr89RocZ

iTrader: (20)

Verify balancer hasnt slipped and timing is correct?

What fuel grade? 93 oct?

So going richer didnt help, and pulling timing didnt help? Thats interesting. Starting to seem unrelated to tune and some other issue. Real rich typically doesnt stutter, usually a lean issue.

Then again... Being a manual it could be lugging abit at those low rpms even tho the lv8 is low. Take fueling back closer to 128
Again but try giving it 6 deg more timing to 30-32 deg and see if that helps

RBob

iTrader: (1)

Hmm, bunch of stuff here, thinking out loud, I'm not sure of the time scale on the graphs. It is shown as Time (M.S.), but it can't be in milli-seconds as the data rate isn't that fast.

And a rapidly changing INT is relative. It appears that with lower proportional gains it took longer for the INT to cycle a cross-count. That combined with the current injectors and it is likely the opposite, there isn't enough proportional gain.

Not sure if you want to continue tuning with the current injectors, but you can do some things to narrow down the stuttering. Put the fueling back so closed loop BLM is in the 128 range.

Then set the closed loop temperature threshold high to force open loop. See if the stuttering is gone. If so then it is due to the proportional gains.

When you get the replacement injectors, start over with the MAF tables & scalars along with the injector flow rate constant. Post a picture of an injector that shows the part number. If I have compensation data I'll post it.

RBob.

Keoman

iTrader: (3)

Timing is correct, 7* and set the same in the Bin.

running 91 octane (no 93 due to high elevation here)

I am going to wait till the new injectors get here and put them in before I tune anymore, as tuning for the wrong injectors seems like a waste of effort.

Thank you very much for the suggestions and help. Will try dialing in closed loop BLM's and then forcing open loop. Will also try adding timing down low and see how it responds.

Will report back in a few days.

Keoman

iTrader: (3)

Well, gotta give it to Southbay Injectors, the injectors arrived yesterday. Was not home until late and didnt notice they had arrived.

On the other hand, the injectors I received are labled with 280 155 771

The Stan Weiss list you referenced (Rbob) puts these injectors at 17 #/hr @ 3bar
Is this true? What injector number do i need to get 22# injectors???

Orr89RocZ

iTrader: (20)

Thats strange. Are they modded to flow more by south bay? It really shouldnt matter what injector size you use, the 19-22 lb ones all should feed that motor once tuned right

RBob

iTrader: (1)

At this point I don't know what to say.

RBob.

Orr89RocZ

iTrader: (20)

Southbay claims thats a 19# injector according to other posts here

RBob

iTrader: (1)

See if you can find a set of these injectors:

FORD RACING 24 LB/HR FUEL INJECTOR SET
M-9593-AA302

They are discontinued by Ford, but there may be some still available. If you get them let me know along with the fuel pressure (vac line off). I'll crunch the offset data.

RBob.

Keoman

iTrader: (3)

Just had a good talk with southbay, they did say the 280-155-771 is indeed a 19# injector.

The first email I sent them included the fact that multiple websites listed the 280-155-700 as a 19# injector. I also included a photo of the injector. They apologized for the mishap and sent the 280-155-771's out over night.

After emailing them today, they said that the 280-155-700 is rated at 19# at "ford fuel pressure" However, they are rated at 22# at 3bar (43.5 psi) despite the fact that the below sites list the injector at 19# @ 3bar

http://users.erols.com/srweiss/tableifc.htm
http://clean.injectorrx.com/bosch-fuel-injectors/
http://www.fuelinjector.citymaker.co...low_Rates.html

I cannot stress how grateful I am for their prompt customer service and it shows they are willing to go the extra mile for their customers.
It might have all been avoided if they had noticed the injector I was using was in fact the right injector in the first place.

Unfortunately, all this puts me right back to square one.

Rbob, if you think that those 24# injectors with new offset data would fix my problems, I will buy some in a heartbeat. I dont understand why the injectors I have wont work though.

EDIT

Found this thread, seems you have already answered this question before and calculated the offset values for the Type III Bosch 22lbs injector.
https://www.thirdgen.org/forums/diy-...gn-iii-pw.html

In post 3, you say to zero out the BPW vs Offset table because "The type III injectors flow more fuel at small PWs then at larger PWs"
As for the Voltage vs Offset, you gave some values here that are (in the lower regions) substantially different than the information in my ARAP bin.

These are my values as they compare to the values below.
5.67627
2.31934
1.49536
1.12915
0.7019
0.48828

RBob

iTrader: (1)

For me, the bottom line is now to purchase MPFI injectors that have compensation data. No data, no buy.

Wish I could do that with TBI injectors...

Anyway, I cant say that purchasing the above injectors will solve the stuttering. But having the injector compensation values goes a long way toward a good tune.

Besides, it seems to me that an injector that flows a little more then stock is going to be required with this engine.

RBob.

Keoman

iTrader: (3)

Frank at Southbay sent me this file for the 155-700's

Is this the data you are suggesting I need?

RBob

iTrader: (1)

That is the data sheet, not sure if it is for the Bosch-III's though. Here it is crunched for 42 psi of fuel pressure (already have it at that pressure):

Injector Data Sheet: M-9593-C302, 19 #/hr yellow tops, EV1

Fuel Pressure: 42 psi
Flow rate: 20.0 #/hr
Minimum PW @ 42 psi: 886 usec

Offset Compensation versus Battery Voltage:
6.4 Volts: 3197 usec
8.0 Volts: 1925 usec
9.6 Volts: 1358 usec
11.2 Volts: 1029 usec
12.8 Volts: 795 usec
14.4 Volts: 633 usec
15.0 Volts: 574 usec*

Put zero's in this table:
Short PW Compensation versus Pulse Width:
0.015 msec: -162 usec
0.244 msec: -143 usec
0.488 msec: -122 usec
0.732 msec: -102 usec
0.976 msec: -81 usec
1.220 msec: -61 usec
1.460 msec: -40 usec
1.708 msec: -19 usec
1.950 msec: 0 usec
2.197 msec: 0 usec
2.440 msec: 0 usec
2.685 msec: 0 usec
2.929 msec: 0 usec
3.170 msec: 0 usec
3.410 msec: 0 usec
3.660 msec: 0 usec
3.900 msec: 0 usec

RBob.

RBob

iTrader: (1)

Here is the data for fuel pressure of 44 psi, closer to stock pressure:

Injector Data Sheet: M-9593-C302, 19 #/hr yellow tops, EV1

Fuel Pressure: 44 psi
Flow rate: 20.5 #/hr
Minimum PW @ 44 psi: 904 usec

Offset Compensation versus Battery Voltage:
6.4 Volts: 3264 usec
8.0 Volts: 1965 usec
9.6 Volts: 1386 usec
11.2 Volts: 1051 usec
12.8 Volts: 811 usec
14.4 Volts: 646 usec
15.0 Volts: 586 usec

RBob.

Street Lethal

iTrader: (16)

Sounds like your misfiring. Check your wires to see if they are arcing, check the boots and terminals to see if they are separating, check your plugs to make sure they aren't cracked anywhere despite their good looks...

Keoman

iTrader: (3)

Rbob,
I replaced the values you listed in the Offset vs Voltage table and zero'd the Comp. vs Pulse Width. The car ran better and the jerking/sputtering moved alot lower in the RPM range, between 700-1000. I was about to start tuning it again and decided to check completely over the ignition system as per Street Lethal's suggestion.

Header burned a hole in my #5 plug wire. Checked a spare wire I had in the garage and replaced it, still idled very rough. Did not have a chance to see if it fixed the stuttering. Ordered new MSD 5562 wire set and set of summit boot protectors. But I didn't stop there...

Had a friend (ex friend?) make my plug wires for me because he said he had done it many times before. He used the Accel 4041k wire kit and terminated the ends himself. I have a Bosch replacement wire set laying around and decided to compare the resistance on the two wires. Results are a bit off-putting also...

Accel Wires averaged 3300-3600 Ohms/ft
Bosch 7mm wires averaged 400-500 ohms/ft
Spare summit 8mm wires averaged 40-55 ohms/ft

is this the problem? I feel like an idiot...
perhaps I should be posting in a different section of the forum.

ignition system is stock except for the Autolite 605 plugs regapped to .035"

lakeffect2

I've been using the ceramic booted spark plug wires ( big bucks) for a few years now. Was constantly having burn through issues with conventional (cheap) designs. I also still use the cloth boots on them to keep them away from the pipes, and haven't had a burn through since. I checked the wires once a month to look for problems, none so far..

Dave

PS. thanks RBob for all your past help.

Keoman

iTrader: (3)

That single wire was a Bosch temporary stock replacement wire with a rubber boot, not silicone. (hence the melt down) All of the Accell wires have silicone boots and look remarkably good.
Something I dont understand, however, is why the Accel Radio Suppression core wires I have average at 3400 ohm/ft while all the other wires I checked are so much lower. (pretty sure more resistance in this case is bad) I even went out today and cut the ends off a foot of wire, stripped and measured the resistance without a crimped connector on the end, came out with 3412 ohms.

In any case, received my new msd street fire wires, hooked them all up, verified BLM's from 7-20 gm/sec. Still have a choppy rough idle and BAD jerking/stuttering from 55-70 LV8.

I'm not sure what else to do.

Keoman

iTrader: (3)

Didn't want to leave this thread open.
Thanks Rbob for all your troubleshooting help. Not for one second do I think all this was in vain, I learned a ton and received good offset tables from you.
Thanks again.

Two major issues with the heads.
Both heads were cracked, one head had a crack on the exhaust seat of one cylinder.
Before removing the heads, did a leakdown test on all the cylinders, air was PISSING out of every single one of the intake valves. Can only assume the same about the exhaust.
Took the heads to a new machine shop (found out they were cracked) told me guides had never been replaced nor had the valves been ground at all.
Got screwed by the first machine shop for a complete valve job (thanks Crankshaft Grinders of Salt Lake City)
Looking for a replacement set now.

Dominic Sorresso

RBob,

Is using zeros something you would suggest for all injectors in the Low PW table?

Keoman

iTrader: (3)

quote from another thread

I am currently fighting the overlap lean condition as everyone else has put it.
Still fighting the stutter after new heads. But Its getting better the more I play with the o2 settings.