Another C5 Corvette Z06 that starts and dies.

[jonathan eme]

Hi Guys,

After so much time spent trying to find this on my own, I'm out of ideas. I don't like to post on any forum until I've exhausted everything in my knowledge.

Long. and short, we were driving the car, made a hard pull, and now the car just starts/dies.

2004 Corvette Z06, LS6
-built block by previous owner
-A&A supercharger kit
-Holley mid-rise manifold
-LS3 throttle body, silver blade
-1000cc injectors
-A&A dual fuel pump kit
-External FPR
-Headman headers, no cats
-E85
-MAF delete, air intake temp sensor installed


The car has run for over a year on this exact setup and file. The file was created by a member on Corvette Forums to help me get the vehicle to understand E85. I am not a ''tuner'', but I have gotten the car to run very well, conservatively.

We've changed the ignition switch, cleaned EVERY ground, disabled VATS (with full write), disabled steering lock (performed brown wire mod), repaired a damaged rear 02 connector, replaced the PCM. The filed attached will be for each PCM, the logs don't last more than a few seconds.

I'm really hoping that I'm just missing something obvious, I don't have the pride or time to care how foolish I look. I've been working on cars for a long time, but this has me stumped... Please HELP! I'm happy to provide any other info.


car dies 1.hpl
car dies 2.hpl
2bar tune 2 -E1.1.1 use 18.hpt
new pcm tune NO VATS, no column lock no maf.hpt

[5FDP]

The MAF dtc's need to be on MIL on first error for speed density.

[jonathan eme]

Thank you for the reply. I?ll give it a shot.

Looking back at old tunes, that?s how I had it set up, but somehow it?s off now.

[blindsquirrel]

Wow, that's the first Gen3 file I've seen that has MAF Fail Low/Low Count Thresh settings.

[Alvin]

Hi Guys,

After so much time spent trying to find this on my own, I'm out of ideas. I don't like to post on any forum until I've exhausted everything in my knowledge.

Long. and short, we were driving the car, made a hard pull, and now the car just starts/dies.

2004 Corvette Z06, LS6
-built block by previous owner
-A&A supercharger kit
-Holley mid-rise manifold
-LS3 throttle body, silver blade
-1000cc injectors
-A&A dual fuel pump kit
-External FPR
-Headman headers, no cats
-E85
-MAF delete, air intake temp sensor installed


The car has run for over a year on this exact setup and file. The file was created by a member on Corvette Forums to help me get the vehicle to understand E85. I am not a ''tuner'', but I have gotten the car to run very well, conservatively.

We've changed the ignition switch, cleaned EVERY ground, disabled VATS (with full write), disabled steering lock (performed brown wire mod), repaired a damaged rear 02 connector, replaced the PCM. The filed attached will be for each PCM, the logs don't last more than a few seconds.

I'm really hoping that I'm just missing something obvious, I don't have the pride or time to care how foolish I look. I've been working on cars for a long time, but this has me stumped... Please HELP! I'm happy to provide any other info.


car dies 1.hpl
car dies 2.hpl
2bar tune 2 -E1.1.1 use 18.hpt
new pcm tune NO VATS, no column lock no maf.hpt

You've verified fuel pressure correct?

[jonathan eme]

Thank you, all for the replies. I?m hoping my experience can help someone, no matter how much of a pain it is for me.

We have verified fuel pressure, 58 psi base. We have even bypassed the factory fuel pump by using A&A fuel pump, and I?ve also used VCM scanner to manually turn on the fuel pump while cranking. It seems as though the car is either shutting off the ignition coils, or shutting off the fuel injectors.

I have attached the most current file, we even did a ?write entire?


2bar tune -original ECU, SD, no VATS, no steering lock, E85.hpt

Thank you all again for your input so far

[2xLS1]

You don't need to write entire to turn off VATS on a 04 P59 Write calibration will suffice. If you've been working on cars for a long time like you said you should know how to test for spark and check for injector pulse with noid lights or even test if it will run spraying starting fluid into the air intake tract.

[jonathan eme]

You don't need to write entire to turn off VATS on a 04 P59 Write calibration will suffice. If you've been working on cars for a long time like you said you should know how to test for spark and check for injector pulse with noid lights or even test if it will run spraying starting fluid into the air intake tract.

Everywhere I?ve read (emphasize my research) has said full write for OS and VATS changes.

If you don?t wish to help, that?s ok. I?m looking for input or guidance through dialogue from people who are interested in the outcome, or have experienced this issue. Thanks.

Starter fluid in the intake tract worked briefly, but again, the car doesn?t stay on for more than a couple seconds either way. With any fuel forced in, the car still shut off, but back fired.

No codes are coming up, making it even more challenging

[gtstorey]

If you can’t keep it running on starter fluid then it’s likely cutting the ignition.

[2xLS1]

On E40s and E38s where the VATS is in the OS Tab a write entire is required. It's not there in P01 and P59s. And I did give you guidance. Sorry you didn't recognize it.

[jonathan eme]

On E40s and E38s where the VATS is in the OS Tab a write entire is required. It's not there in P01 and P59s. And I did give you guidance. Sorry you didn't recognize it.

I’ll take a step forward since I’m just looking to get the car fixed and apologize for my confusion.

Im passed the basic checks and I feel like this is well beyond some basic air/fuel/supply issue. The car starts and runs, no misfire, no abnormal noises. Idle is normal. It just doesn?t stay on. Runs for 2-4 seconds at best, but starts every time. No codes, none.

[reubone]

Have you tried to pedal it to keep it running? The really low idle and shut down could be a fuel or an airflow issue. Its all I can see in the logs so thats what I am going by. Look like a typical big cam hard start issue and should be able to be tuned out the same way. Again just going off the data. Let us know what all you have tried so far and data log every time you try to start it so you can share

[reubone]

Try flatlining the mar calibration from 3000 down to 1500. Ive had to do this on some maf failed sd tunes to get start up
Screenshot (99).png

[SiriusC1024]

You were running and then not. Bits didn't get flipped in the memory of the ECU. Something broke. There's no fuel (it seems). One thing that can cause that is a bad cam position sensor. Sure there's no code, but it probably got erased and won't reset.

One way to check is to log injector duty cycle. Go ahead and start logging MAP, too.

[Alvin]

On E40s and E38s where the VATS is in the OS Tab a write entire is required. It's not there in P01 and P59s. And I did give you guidance. Sorry you didn't recognize it.

This is my understanding too.. GEN 3 doesn't need a WRITE ENTIRE.

However some guys in my office have found instances were they seemed to need to do a WRITE ENTIRE on GEN 3 for vats to be disabled. They tell me they had a couple that wouldn't work until they did a complete write. I haven't seen it personally but I trust the guys here. So.. Long story short.. maybe something changed, its not my experience but maybe gen 3 does need a write entire at least in certain cases.

[2xLS1]

I have turned off VATS on over a hundred red/blue PCMs for swaps and have never done a write entire. And I'm not exaggerating on that number.

[Alvin]

I have turned off VATS on over a hundred red/blue PCMs for swaps and have never done a write entire. And I'm not exaggerating on that number.

I'm with you.. Same situation here.

Still guys here are warning me they had a couple cases were it didn't work until they did a write entire.

[aaronc7]

You were running and then not. Bits didn't get flipped in the memory of the ECU. Something broke. There's no fuel (it seems). One thing that can cause that is a bad cam position sensor. Sure there's no code, but it probably got erased and won't reset.

One way to check is to log injector duty cycle. Go ahead and start logging MAP, too.

All of my thoughts are captured in this post. You know the tune is/was fine, I wouldn't go changing anything with the tune which will throw even more variables into the mix.

I was going to recommend logging inj PW and MAP too. One thing I like to verify early on is that all sensors are reading normally-- check to make sure MAP is reading correct pressure key on engine off, and logging inj pw may give insight into if the PCM is injecting too much or too little fuel or stops at some point.

[jonathan eme]

Thanks for the latest reply’s.

One person asked about throttling to keep it on, that does nothing. No matter what input.

I’ll get another log going.

And I don’t necessarily think something just got flipped in the tuning, I’m just out of ideas. We’ve checked every ground, every connection. I just know that there’s a lot of guys on here who done GEN three tuning, who may see something I’m missing ��

[jonathan eme]

Ok. I got my brother to send me the log using my laptop. I can?t see the log info since I?m typing this from my phone. If I can get my laptop from him soon, then I will try to take a peek myself. But I have attached it here for now, so anyone here can tell me what they see if they find time, thanks again!

car dies 6-7-23-2.hpl