torchredfrc

Took the car out about 2 weeks ago and everything was running great. It sat for about a week then last Saturday I took it out and about 15 minutes into my drive the car got real loud. The check engine light came on solid then started blinking and the car was obviously misfireing. I limped the car home and let it cool over night.

The next day, I pulled a few of the plugs on the drivers side to find them black. Aparently gas fouled. I went ahead and pulled all the plugs and found the same thing on both banks. Last night I replaced the TR55IX plugs that were in the car with a set of old plugs I had laying around that were not fouled. The car is still misfireing bad. There is a heavy gas smell out of the tail pipe and some smoke which I expected since the car is running so rich.

I'm confused at this point though. The plug wires are fairly new as were the spark plugs. I've had the TR55IX plugs in the car for around 30k miles and the plugs on for around 10k miles. I did a search after trying the plugs last night and found some other CF members with similar problems that had the #22 fuse blown. I checked all the fuses and didn't find any bad.

After checking the codes (I had P0300 as well as a "Lost communication with the PCM & BCM" codes) and resetting them I tried starting the car again but got the same results. However, the only code that continues to reset is the P0300 misfire code. I have checked the O2 sensor wires on both banks and they look ok. The passenger side O2 sensor in my car is a LM-1 wide band that emulates the stock narrow band. The drivers side O2 sensor is the stock rear O2 sensor and has about 75k miles on it. I don't find any wires exposed or shorted in the looms feeding the coil packs and injectors and I checked the MSD plug wires visually.

So far I'm thinking I could potentially have something wrong with my PCM. When I took the car out 2 weeks ago it was raining outside but I didn't drive through anything abnormally deep and the car ran fine all the way home through start and stop traffic and on the highway. When I was driving last Saturday the roads were clear, I don't think I ran over anything, and it ran great for the first 20 minutes of my drive.

Any suggesions for troubleshooting this problem is a great help. I'm at a loss here.

My car is modified in the following ways:
MTI C2 224/224 .571/.571 112LSA camshaft
LS6 intake
LG Pro LT headers, no cats.
LM-1 Wideband O2 sensor - emulating narrow band
Various cosmetic / interior mods not pertinant to this post

I have made a zip file containing my HPTuners bin file I was running as well as a dump I made of the PCM after it started having problems. I've also included 2 logs from how the car was running when it ran fine. There is one log that is a short drive with it misfireing and 2 JPG images of how my LM-1 is setup as well as a brief explanation for how I configured the LM-1 to emulate the stock narrow band sensor.

Logs are available here:
http://www.thend.org/~mkane/Corvette/misfire_logs.zip

joecar

With a scan tool, read your HO2Sx1 voltages and LTFT's.

torchredfrc

Joecar, thank you for your reply. In the zip file I have linked in my post I have included 3 different logs (scans) of the car. These scansa re in HPTuners log format but I would be more than happy to export them to a comman separated variable file that you could view in Excel if you wish to see these values.

What are your thoughts? I already know the car is running rich and it is very obvious when the O2 sensor voltage and LTFT's are displayed.

joecar

Oh, sorry, I didn't see the zip at the end of your post (I am having a day...)

Edit: sorry, I don't have HPT, I can't view your logs; can you post pics (.png) of portions of your logs...?