engine misfiring and dumping fuel

[johnnycasx]

Hello i have a situation with my vehicle. when i start my vehicle up, my car runs ok for the first 2 minutes. after that my car runs like its dying. the o2 millivolts reading start at high 400's and when its warmed up it drops down to almost double digits. my block learn is at 142. i have had an ls1 MAF along with a translator, angled IAC, ally kit. new 160 degree t-stat and turbo tweak chip V5.7 I have asked a knowledgeable TR guru and they said it sounded like a O2 sensor problem. was wondering if any one can concur with me on that weird problem. i have been using top tier gas from BP as well.

thanks,
John

 

[aminga]

Scan Tool Data?

 

[johnnycasx]

when cold scan master has o2 millivots at almost 5 00 millivolts. when it reaches operating temperature it goes very low to 171 to 100 millivolts. block learn is at 142. croos counts are all over the place.

 

[NY_GN]

If you replace the O2 sensor and still have the issue, check the CAM sensor cap. I had that problem when it wasn't adjusted correctly, MV's went from 200 to 700 and all around. Also, BP gas is horrible (Shell, Chevron, Exxon=less mystery winter mix.

 

[TurboDave]

MV's went from 200 to 700 and all around. .

MV moving all over is normal closed loop operation.

 

[NY_GN]

It's moving more rapid than before the CAM sensor switch and has slight hesitation. I don't want to hijack his thread, just offering up other possibilities. I'll trouble shoot my issue when the snow melts.

 

[Eric Stage I]

What are all the Translator settings set to currently?

 

[johnnycasx]

i will check the cam sensor. the sensor was rebuilt and has a caspers LED cap on it(according to previous owner, this was done last year). still has orignal o2 sensor on it, so i will order a heated o2 sensor from caspers and try that. as for the translator setting, I'm gonna check that later tonight or possibly tomorrow, Cottons set it up when my turbo tweak and alky kit were installed. i'll post the setting later on.

 

[aminga]

when cold scan master has o2 millivots at almost 5 00 millivolts. when it reaches operating temperature it goes very low to 171 to 100 millivolts. block learn is at 142. croos counts are all over the place.

Cross counts are supposed to be all over the place in closed loop. OT sensor is probably OK. But the O2 mV should also be moving. Does it count from 0-255 in the space of a few minutes?

The block learn says lean or airleak

 

[johnnycasx]

i was told that the induction system is ok per when I had all this work done. i'd have to check tonight to see if what the readings are again. i know it moves rapidly. when i touched the wire on the O2 sensor when at operating temp it went from 170 to 500(harness side seems ok).

 

[lolo86GN]

Check for vacuum leaks. I had a bad leak that made the car do exactly that. I plugged off all the hoses at the vacuum block. It turned out to be a bad pcv valve.

 

[johnnycasx]

I'll have to smoke the induction system to find the leak. i'll replace the oxygen sensor with a heated one for the sake of updating it.

 

[aminga]

you don't need a heated O2

 

[johnnycasx]

ok I checked it out before the big game last night. when i started it, it was running at 394 millivolts at cold start. when giving it slight throttle blast it jumps to almost 800 millivolts. then, once it warms up it goes to 171 to 90 millivolts. int is at 128 and BL is at 142. AF is stuck at 8. if i drive it hard the AF goes to 99 to 1. turbo spools but lags heavily and lacks power.

 

[LelandLs6]

ok I checked it out before the big game last night. when i started it, it was running at 394 millivolts at cold start. when giving it slight throttle blast it jumps to almost 800 millivolts. then, once it warms up it goes to 171 to 90 millivolts. int is at 128 and BL is at 142. AF is stuck at 8. if i drive it hard the AF goes to 99 to 1. turbo spools but lags heavily and lacks power.

If you haven't yet check all your fittings from your turbo to your TB for leaks... Sounds weird I know but a local guy here had a problem similar to yours and we looked over everything with no luck... Week later and he's under the car and noticed he had a torn intercooler coupler... Didn't make a hissing noise or anything like that which was why we had overlooked that.

 

[johnnycasx]

i thought i heard an air leak coming from somewhere. i wanna say that the cold air kit is a little old and the silicone hoses my be past their prime. i gotta get my hands on a redline EVAP smoke detector to really find the leak.

 

[aminga]

ok I checked it out before the big game last night. when i started it, it was running at 394 millivolts at cold start. when giving it slight throttle blast it jumps to almost 800 millivolts. then, once it warms up it goes to 171 to 90 millivolts. int is at 128 and BL is at 142. AF is stuck at 8. if i drive it hard the AF goes to 99 to 1. turbo spools but lags heavily and lacks power.

AF is not Air/Fuel it's Airflow and it should hit 255 at about 15PSI. If this a stock or reman maf then it's time for a translator and a LT1 maf

 

[johnnycasx]

already got an LS1 maf with translator