ksphar

I have a 92 LT1 that is running rich at idle. During open loop, the blm's read locked at 120. As soon as it hits closed loop, they quickly drop to 108. It is running extremely rich. Mods are 1.6 rr's and a BBK 52mm TB. Could the TB be causing this problem? I also noticed on Datamaster that my target idle speed in the computer is 763 RPM. Yet the car idles around 850. Is that correct? I was comparing it to some files i had from a 96 Z28 and it's target idle speed and where it actually idled were identical? I have checked nearly everything and am wondering if this could be a bad ECM. It has a remanufactured sticker on the outside of it.

bogus

are you getting data from the ECM? Then I doubt that's the problem.

What numbers are you getting off the O2s?

I don't see how the TB would cause this, unless there is a small vacuum leak.

I am not sure how you can compare a 92 LT1 with a 96 LT1... they are very different... the 92 being batch injected, OBDI, whereas the 96 LT1 is sequential injection with OBDII.

MrNuke

Are you using an aftermarket chip?

ksphar

I am not using an aftermarket chip. I switched back to the stock throttle body and it helped, but it is still running rich in my opinion. Are the stock programs just that rich? Does the batch fire run that much different from the later cars?

ittlfly

What are your O2's reading? Checked for vacuum leaks?