Started up 24x conversion, running super rich-scanner readings inside.

[green96ta]

Alright, I got a start up tune from a tuner so I could get the car running and then drive it to the dyno. well Its running so rich that it fouled the plugs in just two short idle sessions. Here are some mac scanner readings, both key on engine not running and engine running. If I rev the engine it will die when it comes back to idle. I believe that there is something wrong with the injectors in the tune, My fuel pressure is 41 at idle and if I rev it it drops to 38 psi. I changed the pump strainer, and the fuel filter. I know the pump is good, its a 255lph walbro. please help me figure this out as I would LOVE to drive my car.

Key on engine not running
ECT-106
IAT-86
Desired IAC air- 29 g/s
Bank 1 O2-108mv
Bank 2 O2-40mv
Open Loop
Map-29.23 iHG
MAF- 8.47 g/s

Engine Running (like shit) Idle speed
ECT-124
IAT-86
Spark 29.5 Degrees
IAC posistion- 160
CMP Hi and Low signal both 1942-2200
Fuel trim cell BLM 20
Bank 1 O2-113mv
Bank 2 O2-30mv
Open Loop
Map-3.6v
Map- 23.33 iHG
MAF- 14-16 g/s
Short term fuel-Bank 1-18.8% to 22%
Bank 2- 18.8% to 40% ???

[gregrob]

Did he assign the injectors to each bank correctly?

[green96ta]

I would think he did, this isnt the first 24x he has done. who knows. It ran perfect until it fouled the plugs. The best lead I have gotten so far is someone on ls1tech mentioned that by the o2 readings it is running really lean, so its dumping fuel to compensate and that is why its fouling the plugs.

[Z28pr0jekt]

Your IAC is running wide open which will cause the computer to dump fuel in

[gregrob]

Your IAC is running wide open which will cause the computer to dump fuel in


This is very true. Between the 02 readings and the IAC that is the biggest part of your problem.

Are the 02s new?

I would ohm out the 02 part of the harness and make sure thats all good to go.

Also, on the IAC did you run a new ground for it? Im pretty sure the LS PCM wants to see a dedicated ground to all the sensors. Althought I'm not sure if it would just throw a check engine light, or actually make the IAC default all the way open. Just something for you to check possibly.

[green96ta]

Your IAC is running wide open which will cause the computer to dump fuel in

I didnt know that 160 was max. I tried resetting it and it wouldnt reset. so im gonna ohm it now.


This is very true. Between the 02 readings and the IAC that is the biggest part of your problem.

Are the 02s new?

I would ohm out the 02 part of the harness and make sure thats all good to go.

Also, on the IAC did you run a new ground for it? Im pretty sure the LS PCM wants to see a dedicated ground to all the sensors. Althought I'm not sure if it would just throw a check engine light, or actually make the IAC default all the way open. Just something for you to check possibly.

The o2s are delphi and have very little miles on them. I re done 90% of the connectors. Im positive the wiring is good. I triple checked when I done it, and now ive triple checked it again. lol. As for the IAC wiring there are 4 wires and all wires lead to the pcm.

EDIT- Tested the IAC per http://shbox.com/1/iac2.jpg

and I got 55 ohms on both tests, so I guess its bad. It will not reset.....tomorrow morning im going to pull the tb and the iac housing and have someone cycle the key and see if it moves. then ill know 100% that its the iac.

[Z28pr0jekt]

Yea did you ever take the IAC out for the build?

I had one on my cam only setup that was reading "a little" high. But it was still modulating and opening and closing according to the datalog. Well come to find out when I disassembled my TB for my turbo build the IAC spring was caked in garbage and completely compressed and would not move a centimeter. So that was the cause of my cam only setup running so rich which I ended up drilling out the IAC hole a bit larger without ever actually removing the IAC and checking it.

And for reference, when the IAC was in like that before i drilled the IAC port, the car wouldn't hold an idle while I was coming to a stop and was causing my tune to be all screwy

[green96ta]

Yea did you ever take the IAC out for the build?

I had one on my cam only setup that was reading "a little" high. But it was still modulating and opening and closing according to the datalog. Well come to find out when I disassembled my TB for my turbo build the IAC spring was caked in garbage and completely compressed and would not move a centimeter. So that was the cause of my cam only setup running so rich which I ended up drilling out the IAC hole a bit larger without ever actually removing the IAC and checking it.

And for reference, when the IAC was in like that before i drilled the IAC port, the car wouldn't hold an idle while I was coming to a stop and was causing my tune to be all screwy

i bought a new gm IAC since mine had 100k plus miles on it. That wasnt the issue though. the problem is the count ratings in the tune had not been changed from ls1 counts to lt1 count numbers. Ls1 has 300 plus steps and lt1 has 160 max

[Z28pr0jekt]

So did that fix it?

[green96ta]

So did that fix it?

no. I have hptuners on the way, it will be here tomorrow. I will fix it when I go into the tune and correct the counts.