was running great now its not??

[bcar]

I have a 98 vette that i changed to an 01 ECM. I don't drive it much and something has went wrong, it will bog and not accelerate. Since it started doing this I checked for trouble codes and had one for the Front O2 sensor. I replaced both but did not resolve the issue, there is no new codes. I do not do my own tunes and use this more for diagnosing and small tweaks. I haven't messed with HP in a while so I am a bit rusty with the information in the log. I have the log and tune posted, any clues what my issue is?
Also since i looked at this apparently my tuner left it speed density from when it was supercharged....... My own idiot fault for not looking at it myself.

[podium]

Its using a speed density OS for sure. Looks like your O2s are working like they should looking at your scan. So you were supercharged and then went back to NA?

[bcar]

Yes, was supercharged on E85. Had to sell supercharger and later ended up swapping to trick flow heads and a Fast 92 intake. I am beating myself up for not looking over the tune after it was redone for NA, I am afraid they really didn’t do much on the retune. I am trying to find my hard drive that has the supercharged tune on it to verify that. It ran great last fall but something happened and I am trying to figure out what it is before I do anything to the tune.

Also thanks for looking

[Lakegoat]

Your MAF is failed but it is not ready in speed density. Go to DTC's and make P0101,102,103 to Mil on first error. There is nothing wrong with sd if you don't have a maf anymore. Looks like you are going into PE too soon and the ramp in is 4. Maybe change this to 2 and raise the hot pedal enable. I'm not sure where na motors like the MAP enable, but 15 seems a little low to me. Your VE table needs to be redone as that is what you are running on for fuel. At idle, one of the stft's sat at -50 for a long time. Check that out. Looks like your spark tables are reversed? The low table has more timing that the high table and it looks like you are still running the E85 spark?

[bcar]

Your MAF is failed but it is not ready in speed density. Go to DTC's and make P0101,102,103 to Mil on first error. There is nothing wrong with sd if you don't have a maf anymore. Looks like you are going into PE too soon and the ramp in is 4. Maybe change this to 2 and raise the hot pedal enable. I'm not sure where na motors like the MAP enable, but 15 seems a little low to me. Your VE table needs to be redone as that is what you are running on for fuel. At idle, one of the stft's sat at -50 for a long time. Check that out. Looks like your spark tables are reversed? The low table has more timing that the high table and it looks like you are still running the E85 spark?

Thanks for the info, I don't have a problem with sd. I was afraid it wasn't right, I saw the stft like you did and knew that was an issue. I can't figure out how it seemed to be running right for a while.
Thanks for the help, I will look into all of this.

[someblackguy224]

Because you mention not driving it often i wonder, Is the gas still good? i do not see a mention of the current fuel selection. you say tuned for E85, what gas do you have in it now? That could also explain the -50 STFT.

[bcar]

It was supposedly retuned for 93 and that is what is in it. Before I went for a drive I drained the fuel and put in fresh 93. I contacted the dyno shop that swapped the tune back to NA and 93 (or didn't)but haven't heard back from them yet. I have the supercharged tune somewhere and I am going to try to find it tonight and do a compare. Unfortunately this is apparently another example of if you can't do it yourself check all the work someone does for you.

[bcar]

Well it looks like I found the old supercharged E85 tune....... Apparently something was done. Looking like a good time to start completely over......

[bcar]

Finally getting some time and money to put everything back together. Looking at the logs any idea what could have happened to make it run bad? I found out some more information about the tuner and possibly at one time this was good? I know there is no way the spark table was ever correct......
Would a intake leak cause an issue like I am seeing?

[bcar]

I did talk to the shop that did it, the tuner is well known around here and supposed to be very good. If it was right in the first place fixing it would be very easy, they pretty much told me to pound sand and wants $500 again to fix it.....
that is not going to happen.

[DrLoch]

Since you have both files re-tuning will be easier. Replace the 2 Bar MAP with a 1 BAR change the cal. As your tuner stated if the tune was good changing back will be easier but you will still need to re-tune.