LT1 High Idle

[bentrod]

for 93 lt1, TECH 1 or equivalent tool can manually control. Probably applies for your year too. Though if counts at 0 and you're idling at 1600rpm, sounds like something else is wrong like vacuum leak or tuned too lean (e.g. injector values incorrectly set).

Maybe check IAC pintle seat for obstructions/jams? Also all intake related gaskets good and hoses/blockoffs in good shape? You can spray starter fluid to listen to rpm change sometimes.

[ReidB]

for 93 lt1, TECH 1 or equivalent tool can manually control. Probably applies for your year too. Though if counts at 0 and you're idling at 1600rpm, sounds like something else is wrong like vacuum leak or tuned too lean (e.g. injector values incorrectly set).

Maybe check IAC pintle seat for obstructions/jams? Also all intake related gaskets good and hoses/blockoffs in good shape? You can spray starter fluid to listen to rpm change sometimes.

Thanks guys. I checked for vacuum leaks with carb cleaner, hard to get good feel with the high rpm. Pumped intake full of smoke (finally a good use for a year old cigar) no leaks. Replaced IAC, reset pcm, fired up and rpm came right down.

[steveo]

that's good,

now what are your IAC count at hot idle?

[ReidB]

that's good,

now what are your IAC count at hot idle?

Didn't let it run up to hot but running 4-8 counts at 560-600rpm, 150deg F. Hasn't been down the road yet. Sounds good but smells rich. Showing AFR 14.2, O2s 448/457, injectors 3.1. Need to get off the blocks to blow out the cobwebs.

[ReidB]

Still have dead oil press, temp, fuel gauges. Strange, seems like they are all hardwired but the circuitry on the cluster disappears into a black hole. Totally confused. Seems like it should be either hardwired or data bus, not some of both.
I did try a buffer chip to isolate the signals between the 2 pcms. Seems to work good, the tach works now, no more floating voltages.