Autopsy of a z06

[mJolnir]

Yesterday i was working with a z06, the car is a 2015 manual, it has an AFE intake, kooks headers, o/r X pipe and a ATI 15% overdrive pulley, the owner wanted to get the max out of the car so we emptied the tank and put 10 gal of VP ms109 in it.

on the third dyno pass the car put down 625whp and AFR was the commanded 12.2-12.3 on the whole rev range, this is the log from it
dyno109oct3.hpl

On the 4th pass i decided to add a bit more fuel to get it to 11.9-12.0, as the knock sensor was pretty happy i added 3 more degrees of timing in the whole range, but the car didn't seem to like it as it put down 625whp again, here's the log
dyno109oct4.hpl

so i decided to take the fuel out again and leave the timing the same, but the car wouldn't start, there is fuel pressure and it has a very strong smell of gasoline so its not fuel, we disconnected the #1 cylinder spark plug wire and there is spark, but the car just kept cranking and nothing, in the scanner i can read RPM when cranking so its not the crankshaft sensor and no codes.

After a while trying it started using flood mode black smoke came out of the exhaust and there was a random misfire code, the car wouldn't idle and after that it wouldn't start again so we decided to change the sparkplugs, it started once again in flood mode this time white smoke came out and the fuel smell was so strong we had to get out of the dyno cell until the ventilation system got the smoke out.

So today i will be doing a compression test with a knot in my stomach as this could be the first time i hurt an engine and i dont even see anything wrong in the logs, so i decided to post this here and maybe someone more knowledgeable than me can see something off in the tune or logs.

tune2-109oct.hpt

this is the tune

[SultanHassanMasTuning]

pull the spark plugs and see what they look like

[tbrtuning]

I don't tune a lot of LT4 but just from some I've seen and tuned I don't see how you would have hurt it on that tune. Probably didn't make extra power on the last pass because they don't like being that rich. You had plenty of timing in it to be safe at that AFR though imo

[tunerpro]

I agree, pull the plugs. I've heard of that fuel causing spark plug erosion. If the plugs are OK, I'd start wondering if there was an injector failure.

[g26er]

Are you trying to keep the car in PE all the time? Curious why your PE Enable Torque % table is only 10% up to ~3k then only goes to 15% ~5.6k?

I see Flex fuel disabled and usually the stoich AFR table is around 14.2 all the way across but, your's is setup as if you had installed a FF sensor. Don't know if that makes a difference.

Dynamic air is disabled @ 1800 but, even so, the VVE table looks like legos.

I don't know anything about MS109 but, could the car just be stuck in PE and constantly super rich? That would explain fouled plugs (if they're really fouled), smoke and fuel smell.

Sorry if it's not much help, still learning.

[tbrtuning]

Are you trying to keep the car in PE all the time? Curious why your PE Enable Torque % table is only 10% up to ~3k then only goes to 15% ~5.6k?

I see Flex fuel disabled and usually the stoich AFR table is around 14.2 all the way across but, your's is setup as if you had installed a FF sensor. Don't know if that makes a difference.

Dynamic air is disabled @ 1800 but, even so, the VVE table looks like legos.

I don't know anything about MS109 but, could the car just be stuck in PE and constantly super rich? That would explain fouled plugs (if they're really fouled), smoke and fuel smell.

Sorry if it's not much help, still learning.

He should be good on the percent torque because it has to be over that and TPS and TPS looked reasonable. VE isn't going to make much difference as MAF will primarily be used. He said AFR was what he targeted.

[mJolnir]

Stoich table is like that because pump fuel around here is 0% E, put new plugs in it still won’t start, checked compression on the driver side bank and all the cylinders are around 150 psi, I’m now removing the fuse box to acces the passenger side spark plugs

[mJolnir]

The old plugs looked like a very rich tune was in it, but they had 14,000 miles, Some where wet with fuel when I took them out, new plugs went in gaped them at 0.025, the passenger side bank was good on the compression test, it was pretty consistent.

So now I suspect some injectors to be partially open, tomorrow I will take the injectors out and get them tested

[Kyle_Customizer]

Whats your high side fuel pressure? I had one where the VCT solenoid stuck. Believe it or not, that causes the high side fuel to bleed off. There's a GM bulletin on it if anyone wants to look into it. But, the main thing you'll see is high side fuel pressure start around 500-600, then drop to low side psi of 60-70. It will just crank and not start. I had no DTCs either. Using GDS2 I was able to pulse the solenoid and it started working and engine fired right up. Just a heads up, hope the info helps.

[wesam]

It could be a failed Hpfp or stock open injectors

[mJolnir]

Whats your high side fuel pressure? I had one where the VCT solenoid stuck. Believe it or not, that causes the high side fuel to bleed off. There's a GM bulletin on it if anyone wants to look into it. But, the main thing you'll see is high side fuel pressure start around 500-600, then drop to low side psi of 60-70. It will just crank and not start. I had no DTCs either. Using GDS2 I was able to pulse the solenoid and it started working and engine fired right up. Just a heads up, hope the info helps.

while cranking lpfs goes up to 70psi and hpf goes up to 2500psi and starts bleeding, so i believe i might have injectors stuck partially open

[jpierro79]

It wouldnt start after you reflashed it check for codes and disconnect and reconnect the battery do a full ecu write you probably did something like. left the radio on or something during the flash. ive change the vent settings to off during a flash and its screwed up my flash had to disconnect my battery and do a full rewrite on car. I dont think you hurt it. I think you had a flash glitch.when you flash EVERYTHING MUST BE OFF. Do not have anything like an aem x inline with the obd connector. I think your digging to deep. I think its ecu flash gltich related. Ive had my powersteering go into full failure and couldnt clear it with my snap on scanner cause of a flash glitch cause i got a damn call that came in while i was flashing and my radio wasnt even on

[tbrtuning]

I've had a lot of random flash issues on Gen V. I end up doing Write Entire if I question it. Nearly every one I flash will not start first push of button after. It will just crank once and stop then I have to turn it off and it fires up.

Worth trying flashing again

[tbrtuning]

It wouldnt start after you reflashed it check for codes and disconnect and reconnect the battery do a full ecu write you probably did something like. left the radio on or something during the flash. ive change the vent settings to off during a flash and its screwed up my flash had to disconnect my battery and do a full rewrite on car. I dont think you hurt it. I think you had a flash glitch.when you flash EVERYTHING MUST BE OFF. Do not have anything like an aem x inline with the obd connector. I think your digging to deep. I think its ecu flash gltich related. Ive had my powersteering go into full failure and couldnt clear it with my snap on scanner cause of a flash glitch cause i got a damn call that came in while i was flashing and my radio wasnt even on

Thanks for sharing about this because it might be why I always seem to have issues tuning these and have to key cycle them a few times after flashing

[mJolnir]

I've had a lot of random flash issues on Gen V. I end up doing Write Entire if I question it. Nearly every one I flash will not start first push of button after. It will just crank once and stop then I have to turn it off and it fires up.

Worth trying flashing again

I did ty flashing it to the prior tunes including the one the car came with, but thee was no success, but didn't try a write entire

[tbrtuning]

I would try it. I've seen things like put in gear or reverse and converter just slips like crazy and car or truck barely moves... Write Entire and it's good.

[mJolnir]

so just for an update, tried to write entire, the car wouldnt work, also had to change the oil because it was full of fuel

[jpierro79]

clearly one of two things have happened. You either have a true mechanical failure or software corruption. Im sorry to hear this try putting in a ticket with hptuner and see what happens. If the car has stock injectors try bringing someone in to do a full rewrite with oem software. I still dont think you pushed it that far. Then again I had a wrx sti 2015 with 700 miles and had an exhaust cam advencer failure and the actual cam gear assembly had to be replaced. Untuned car too. See if HP can help you out first

[DGS]

It's normal after reflash or battery disconnect to have to cycle push button twice to start. Also some start if you just hold button past initial bump and then it cranks and starts. Appears to be computer sync/reboot after flash or battery disconnect. I've seen factory pumps leak fuel into crankcase when they fail out back of plunger. New pump and oil/filter change.

[mJolnir]

It's normal after reflash or battery disconnect to have to cycle push button twice to start. Also some start if you just hold button past initial bump and then it cranks and starts. Appears to be computer sync/reboot after flash or battery disconnect. I've seen factory pumps leak fuel into crankcase when they fail out back of plunger. New pump and oil/filter change.

this ended up being the problem, hpfp ended u being bad