RacingTiger04

ok im not sure really if this was LT1 engine tech or pcm related... but it seemed more computer like to me... anyway heres the question. mine was broke awhile back when the radiator got swapped out, other than the fact the car was idling a little high and was hard to start it ran GREAT, and ive seen things sold on ebay that do something similar to make it think its running cold like that, so my question is how hard would it be to remove or trick it like this just for races.. or would it even make a real difference? it "felt" stronger but i dont know if it was or not...

shoebox

If you mean tricking the IAT, it does pretty much nothing. Don't bother.

Injuneer

I think he's asking about the engine coolant sensor.

Generally, giving the PCM a false/low coolant temp reading is not going to help you, and most likely will hurt you. As you already discovered, the PCM sets a higher idle speed based on low coolant temperature. It also richens the mixture for low coolant temps, and with stock tuning on an LT1, a richer mixture is the last thing you need. Finally, if the coolant temp doesn't get over 120-140degF, the PCM isn't going to go into closed loop. That can be good or bad, depending on how good the open loop tune is.

shoebox

Whichever he means, neither need to be fooled.

(I haven't heard of anyone trying to fool the coolant temp sensor)

RacingTiger04

ok, looks like i asked in the right forum then. thanks for the info guys! and yeah.. i forgot about the temp req for closed loop. but if you dont mind me asking now that we got into the richness being bad for an LT1, could old O2 sensors (if causing it to run rich) make one run worse? i remmeber someone mentioning my exhuast rasp might be due to running rich from old o2s. any of this possible? (sidenote: i think it would be funny if my exhuast actually helped me to diagnose another problem lol)

Silver

yeah if the o2's get old and tired, the failsafe is to run overly rich to theoretically avoid a too-lean condition... you know the rest of the story.