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Yep something is not right to say the least! Looks like misfire. If the O2 is fouled, it's definitely a false lean condition, but you would see some sooth out of the exhaust.
Also, has your vacuum decreases at lower idle rpm, fuel pressure goes up along ecm opening the injectors more. All that points to false lean condition.
Again 30# on a ZZ502 seems out of place. I have 32# on my 400hp 383 TPI and they are right at the limit of 80%DC. I run 43.5 psi. vacuum disconnected.
I don't know! Quite messy!
30# will feed over 450 hp at a very conservative 0.45 bsfc at 85% DC. At a more realistic 0.40 bsfc they are good for 510 hp @ 85% DC. I have not seen a NA engine need much over 0.40 lb/hr/hp with EFI running a decent air/fuel ratio. I managed 370 wheel hp @ 5,200 rpm through a 4L85E and GM 10.5" ring gear 14 bolt with 24.6 lb/hr on my 383. I had to shut it down early until I put bigger injectors in it.
30# will feed over 450 hp at a very conservative 0.45 bsfc at 85% DC. At a more realistic 0.40 bsfc they are good for 510 hp @ 85% DC. I have not seen a NA engine need much over 0.40 lb/hr/hp with EFI running a decent air/fuel ratio. I managed 370 wheel hp @ 5,200 rpm through a 4L85E and GM 10.5" ring gear 14 bolt with 24.6 lb/hr on my 383. I had to shut it down early until I put bigger injectors in it.
If I follow your estimation, which seems to be coming from an online calculator: 400HP at 0.4bsfc @ 85%DC = 23.5lb/hr, so let's say 24lb/hr.
If I enter 24lb/hr into my simulator, instead of 32lb/hr, and reproduce final INJ PW at WOT with 12.8 real AFR on my 383TPI, I reach 100%DC at 4800 rpm and over 121%DC by 6000rpm (yes it revs to 6k). The final INJ PW includes voltage compensation adder.
If I follow your estimation: 230HP at 0.4bsfc @ 85%DC = 13.5lb/hr let's say 14lb/hr. OEM 230HP LB9 used 19lb/hr from factory (but GM probably did not know what they were doing)
If I enter 14lb/h into my simulator, instead of 19lb/hr and reproduce final INJ PW at WOT with 12.5 real AFR on my 305TPI. I reach 100%DC at 4450 rpm. The final INJ PW includes voltage compensation.
My simulators ($6E or $8D) always match the ecm INJ PW calculation observed with the datalogger by +/- 0.25ms
In both examples real injectors used are 33-35% bigger than your estimation. So let's say: 510HP at 0.4bsfc @ 85%DC = 30lb/hr *1.3 = 40lb/hr
I would have loved to see the datalogger on that 383 run on the dyno with the skinny injectors and 370 whp. AFR must have been on the lean side.
That's just another point of view one would say.
EDITED:
Remember, the '7730 is batch fire, 1 pulse per rotation, 2 pulses for full engine cycle. That adds up on the %DC cycle. WRONG It actually does not change injector size calculation.
The 7730 will EASILY run this setup. Just have to start with the basics and tune it. No such thing as too little idle vacuum. Just have to tune the fuel and spark accordingly. I have done 7730s with about 7 in/hg @ 1,000 rpm idle vacuum. 7730 can easily handle this engine.
You tell that to @Sharp38. He seems to have is hands full
Might be easy for you, but not for everyone. Not very user friendly.
Here are the three parameters I'd be working with to disable the test:
Code:
L8283: FCB 218 ; PK/NEUT HI MAP/BARO RATIO THRESH, 0.85
; ARG = RATIO * 256
L8284: FCB 218 ; DRIVE HI MAP/BARO RATIO THRESH, 0.85
; ARG = RATIO * 256
L8285: FCB 5 ; TPS < 1.9% FOR ERR 33 TO BE SET
Set the two MAP/BARO ratio values as high as they can be set (or as low as possible?). And/or, set the TPS threshold to 0.
Note that unmasking the code 33 diagnostic enable bit likely won't prevent the ECM from creating a default MAP value. The error should still be recognized. It will prevent the SES/CEL and stored code though. Which isn't really what is needed.
Here are the three parameters I'd be working with to disable the test:
Note that unmasking the code 33 diagnostic enable bit likely won't prevent the ECM from creating a default MAP value. The error should still be recognized. It will prevent the SES/CEL and stored code though. Which isn't really what is needed.
RBob.
I suspected so after posting! Thanks for the information. We learn everyday!
If I follow your estimation, which seems to be coming from an online calculator: 400HP at 0.4bsfc @ 85%DC = 23.5lb/hr, so let's say 24lb/hr.
If I enter 24lb/hr into my simulator, instead of 32lb/hr, and reproduce final INJ PW at WOT with 12.8 real AFR on my 383TPI, I reach 100%DC at 4800 rpm and over 121%DC by 6000rpm (yes it revs to 6k). The final INJ PW includes voltage compensation adder.
If I follow your estimation: 230HP at 0.4bsfc @ 85%DC = 13.5lb/hr let's say 14lb/hr. OEM 230HP LB9 used 19lb/hr from factory (but GM probably did not know what they were doing)
If I enter 14lb/h into my simulator, instead of 19lb/hr and reproduce final INJ PW at WOT with 12.5 real AFR on my 305TPI. I reach 100%DC at 4450 rpm. The final INJ PW includes voltage compensation.
My simulators ($6E or $8D) always match the ecm INJ PW calculation observed with the datalogger by +/- 0.25ms
In both examples real injectors used are 33-35% bigger than your estimation. So let's say: 510HP at 0.4bsfc @ 85%DC = 30lb/hr *1.3 = 40lb/hr
I would have loved to see the datalogger on that 383 run on the dyno with the skinny injectors and 370 whp. AFR must have been on the lean side.
That's just another point of view one would say.
EDITED:
Remember, the '7730 is batch fire, 1 pulse per rotation, 2 pulses for full engine cycle. That adds up on the %DC cycle. WRONG It actually does not change injector size calculation.
BSFC of 0.5 is more in line with reality
I guess I will also add 85% is a conservative number as well. GM shipped many of the Gen3 6.0L engines with 25s. Those make close to 400 gross hp at the crank. On stock tune that is pig rich with the WOT AFRs in the 10s and 11s they run 95-100% duty cycle. They will run all day at 100% duty cycle and not hurt anything.
BSFC of 0.5 might be in line with a stock low compression 305 that cannot beathe. One you get into engines that breathe well and have more compression the amount of power you get from the same amount of fuel increases. When the engine has more compression it generates higher cylinder pressure and as the VEs increase the pumping loses decrease. The engine does not work as hard to pull the air/fuel in and push the exhaust out. When you get up to 11-12:1 compression and up to or slightly over 100% VE the BSFC is noticeably better. I have seen worked LT1s and LS1s on the dyno show calculated BSFC readings of 0.38-0.40 while holding 13.5:1 a/f at WOT. I am making ~500 crank hp on E85 with 41s. On Ethanol free 93 octane pump gas the DC is about 60% to get 13:1.
I guess I will also add 85% is a conservative number as well. GM shipped many of the Gen3 6.0L engines with 25s. Those make close to 400 gross hp at the crank. On stock tune that is pig rich with the WOT AFRs in the 10s and 11s they run 95-100% duty cycle. They will run all day at 100% duty cycle and not hurt anything.
BSFC of 0.5 might be in line with a stock low compression 305 that cannot beathe. One you get into engines that breathe well and have more compression the amount of power you get from the same amount of fuel increases. When the engine has more compression it generates higher cylinder pressure and as the VEs increase the pumping loses decrease. The engine does not work as hard to pull the air/fuel in and push the exhaust out. When you get up to 11-12:1 compression and up to or slightly over 100% VE the BSFC is noticeably better. I have seen worked LT1s and LS1s on the dyno show calculated BSFC readings of 0.38-0.40 while holding 13.5:1 a/f at WOT. I am making ~500 crank hp on E85 with 41s. On Ethanol free 93 octane pump gas the DC is about 60% to get 13:1.
In this thread, I was talking about the OP's ZZ502, big block, with 9.6:1 compression on pump gas, with fuel pressure at 43.5lbs, not LSX, LT1, high compression, high VE, E85, dyno this and engine that, etc... As we sit, right now, with his tune, his engine, his set-up, not any other stuff, from the past or future or imagination, it's at 85%DC by 5700rpm and 90% at 6000rpm. I don't have the HP curve for that engine nor the max rpm rev. Maybe it's ok with 30#, maybe it's on the limit. Could not find the recommendations for the OP's Bosh/Fiveo as far as operating range. The newer ZZ502 are rated at max 5800rpm and 9.6:1 compression.
EDITED:
Also I have no clue what the OP's AFR is at WOT and if it's actually rich or lean. My original comment on the injectors was because the OP's tune appeared to have lean VE tables, so by extension, maybe the WOT VE was lean too, thus an increase in VE table at WOT would possibly max out the injectors.
In this thread, I was talking about the OP's ZZ502, big block, with 9.6:1 compression on pump gas, with fuel pressure at 43.5lbs, not LSX, LT1, high compression, high VE, E85, dyno this and engine that, etc... As we sit, right now, with his tune, his engine, his set-up, not any other stuff, from the past or future or imagination, it's at 85%DC by 5700rpm and 90% at 6000rpm. I don't have the HP curve for that engine nor the max rpm rev. Maybe it's ok with 30#, maybe it's on the limit. Could not find the recommendations for the OP's Bosh/Fiveo as far as operating range. The newer ZZ502 are rated at max 5800rpm and 9.6:1 compression.
EDITED:
Also I have no clue what the OP's AFR is at WOT and if it's actually rich or lean. My original comment on the injectors was because the OP's tune appeared to have lean VE tables, so by extension, maybe the WOT VE was lean too, thus an increase in VE table at WOT would possibly max out the injectors.
I would still put his engine in the group of engines that has a better BSFC.
Then again you also told the man he needed to swap EFI systems. Now it is injectors. You are all over the place, TBH.
I is a measure of fuel consumption. 1 lb per hr of fuel at a 0.45 BSFC makes ~2.2 hp. It is a number that is used to get the approximate size of injector needed. Lets say you have 30# injectors on a V8. 30/0.45 = 66.7. Each injector can support 66.7 hp @ 100% duty cycle. Now multiply by 8. 66.7 x 8 = 533 hp. At 85% duty cycle that number is becomes 453 hp. General rule of thumb is you want to size the injector for no more than 85% duty cycle. However most injectors are not harmed at WOT running up close to the full 100% for bried periods. Almost every stock Gen3 6.0L reaches 100% duty cycle at WOT.
Then again you also told the man he needed to swap EFI systems. Now it is injectors. You are all over the place, TBH.
Sometimes it happens when you try to help a desperate TGO member and you have too much on the go. Writing multiple TGO posts on different threads between other daily useless tasks, because I have so much time on my hands. Trying reading datalogs and analyzing data as the wife is requesting me to help with supper. The damn cat jumping on my keyboard or my greasy dirty fingers on my small phone in the shop during my brakes. Sometimes, I lose track of what was said. Sometimes, I think (write) out loud in a brainstorming fashion. I come to forget that everyone is watching, waiting to catch a faux pas. Well! I do the same sometimes. It can be fun and easy. What I know for sure is that some particular TGO members will take me to task, call me on it, lecture me in public and sometimes talk me down, so I get back on track and they can feel good about themselves (aye aye Sir). No shame in that.. What always amazes me though is how little help is provided by the ones who most criticize.
Now that it's behind us, let's get back to topic.
After some private exchange with the OP and a few hours of data analysis, we are confident we found the problem. No it was not the injectors nor the gasoline nor the intake gasket. It was the simple change from CL mode to OL mode under 1000rpm and also full OL mode that created some jitters with the engine. Quite complicated to explain but obvious once you take the time to look at the data frame by frame with context. Not an easy task. Also, there was a failure with either the ecm, eprom or other electronics that made the ecm go crazy on last run. The data made absolutely no sense. It can happen when things are manipulated in an attempt to diagnose a problem.
Sometimes it happens when you try to help a desperate TGO member and you have too much on the go. Writing multiple TGO posts on different threads between other daily useless tasks, because I have so much time on my hands. Trying reading datalogs and analyzing data as the wife is requesting me to help with supper. The damn cat jumping on my keyboard or my greasy dirty fingers on my small phone in the shop during my brakes. Sometimes, I lose track of what was said. Sometimes, I think (write) out loud in a brainstorming fashion. I come to forget that everyone is watching, waiting to catch a faux pas. Well! I do the same sometimes. It can be fun and easy. What I know for sure is that some particular TGO members will take me to task, call me on it, lecture me in public and sometimes talk me down, so I get back on track and they can feel good about themselves (aye aye Sir). No shame in that.. What always amazes me though is how little help is provided by the ones who most criticize.
Now that it's behind us, let's get back to topic.
After some private exchange with the OP and a few hours of data analysis, we are confident we found the problem. No it was not the injectors nor the gasoline nor the intake gasket. It was the simple change from CL mode to OL mode under 1000rpm and also full OL mode that created some jitters with the engine. Quite complicated to explain but obvious once you take the time to look at the data frame by frame with context. Not an easy task. Also, there was a failure with either the ecm, eprom or other electronics that made the ecm go crazy on last run. The data made absolutely no sense. It can happen when things are manipulated in an attempt to diagnose a problem.
So that's it for this one
Cheers and peace to TGO community
Understood. However, I feel I do provide a large amount of information on these boards and always have. The main point I was making was to steer everyone back in the right direction of analyzing data, finding and tuning out the problem before loading the parts cannon. I knew that it could be fixed without swapping the bones aka EFI system or injectors, etc. Pointing out that the ECM and Injectors could handle the engine in terms of having good drivability and running manners even if it were possibly a little short on injector at very high rpm. It also makes sense that full open loop could cause these problems. Open loop is more difficult to calibrate than closed loop because the oxygen sensor feedback adjustment is eliminated. Open loop relies on having properly tuned VE tables, IAT compensation as well as correct injector data. Remove any part of that and the engine will run poorly in open loop especially when it has warmed up and the injector pulse width is shorter. Cold start is not so much of an issue because the air/fuel mixture is very rich anyway and a little more or less does not change the overall fueling as much.
In the end I am glad you found the problem. It is a beautiful car that Sharp38 has.
My comments were not so much trying to chastise but more to help him get this back on the road so that he can enjoy it without having to rebuild his entire fuel system and rewire the whole car. I am sorry if you felt them as a personal attack, because that was not intended. I also forget that many people on here have not been messing with this stuff for ~20 years like I have been. It is easy to overlook the knowledge point of the person you are talking with and leap far over their head.
A win is a win, and if flipping back to 100% CL brings about improvements, that's great. With that said, I would take the opportunity to work on refining the VE tables and other aspects of the tune as necessary such that the tune isn't so reliant on CL feedback. A factory OEM tune you can take the O2 sensor and throw it away, and other than a check engine light and a bit of drop in MPG, you really won't even notice much of a difference in drivability. With a tune so dependent upon CL feedback to be drivable, you're a single failure away from a bad day.
Here are the three parameters I'd be working with to disable the test:
Code:
L8283: FCB 218 ; PK/NEUT HI MAP/BARO RATIO THRESH, 0.85
; ARG = RATIO * 256
L8284: FCB 218 ; DRIVE HI MAP/BARO RATIO THRESH, 0.85
; ARG = RATIO * 256
L8285: FCB 5 ; TPS < 1.9% FOR ERR 33 TO BE SET
Set the two MAP/BARO ratio values as high as they can be set (or as low as possible?). And/or, set the TPS threshold to 0.
Note that unmasking the code 33 diagnostic enable bit likely won't prevent the ECM from creating a default MAP value. The error should still be recognized. It will prevent the SES/CEL and stored code though. Which isn't really what is needed.
RBob.
Tunerpro has the TPS threshold labeled as
ERROR QUAL 33, MAP Voltage-Min TPS% to Set Error
TPS > this% FOR ERR 33 TO BE SET
Doesn't this imply that you'd want to set the TPS to 100%?
02-15-2023, 04:08 PM
It actually does not change injector size calculation.
