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louis
July 15th, 2006, 04:14 AM
C5 Corvette running f1-c procharger with 22 lbs of boost and has been running fine for 6 months. Now all of a sudden it seems to be fouling plugs but last time I took them out they were half white and some were half white and half brown. The tips are white also except for a couple the tips look like burnt blue. Never seen this before.

The car starts up and runs fine till it starts running on about 5 cylinders. I finally got a log on it while it was running fine and when it fouled out. Strange it seems like its not getting enough fuel but watching the fuel pressure is a constant 52 lbs.

Couple other times I took the plugs out they really did look brown and fouled. It actually seems like after it warms up and I try to give it throttle is when it fouls even faster. I am thinking also maybe its an issue with closed loop open loop but not sure how to tell and no idea how to setup a forced closed loop or forced open loop. Could it actually be the wide band 02 sensor?

I am running mafless with 3 bar map sensor, 90 mm throttle body, Dart ls1 cnc race heads, lsx intake, 75 lb injectors.

I even changed the pcm thinking it could be the injector drivers but same issue when changed.

Could anyone explain the open loop closed loop setup and where would I post my log file if someone wanted to take a look?

Has anyone ever had this issue?

Thanks in advance for any help.

caver
July 15th, 2006, 06:52 AM
Fouled plugs are normally pitch black. The real give away is the blue tips. That motor is extremely lean and is about to melt down.
Fit your WBo2 and check the mixtures remember that if its missfiring you will not get accurate readings and a 4 gas analyzer is a better option. Also get a mechanical fuel pressure gauge on it and verify the fuel pressure.

Its possible that you have an injector problem either way dont drive it till you find the problem.
Try and establish exactly which cylinders are cutting out. If the fuel pressure is correct

joecar
July 15th, 2006, 07:52 AM
To post your screenshot of log chart(s)... showpost.php?p=23897&postcount=8 (http://forum.efilive.com/showpost.php?p=23897&postcount=8)

louis
July 15th, 2006, 02:01 PM
Hello.

I ran a few more test and it seems lean is coming in when I lose the right injector back. Made it seem like plugs fouled so I disconnected the right bank injector connector and bent in the seats a litte and was able to fire it up again on all 8 cylinders.

I still have a problem now of running rich and it wont get to 14.6. I see mostly 12.4 and doesnt correct beyond that anymore. I'm not sure how to chk if its in open or closed loop and which is best for it at idle to get it back to stoich.

Included in my log you will see the tune running fair until the injectors on right side intermittently shut off. Once they shut off though this was the only time I took the inj conn and squeezed the female side and was happy it fired up on all 8 again. Just seems something is not switching to open or closed loop to enable correction.

This is also a new ecu because I was thinking it was the inj drivers but no dice.

Main issue now is why I cannot get it to stoich.

Thank you for you time

TAQuickness
July 17th, 2006, 11:02 AM
is it possible your tune was compensating for failing injectors? If so, then it would make sense you are running rich now.

louis
July 17th, 2006, 12:34 PM
Heres an update.

I decided to start with less boost and took my 3 bar map out and installed a 2 bar. I put in a new 3 bar also to make sure it wasnt that. To my surprise it stopped fouling plugs completely.

I am now tuning with a 2 bar then I will try the 3 bar again and see if this happens again.

Thanks for your time