Does the ECM neccessarily need the signal?

[Minime168]

Ive done a swap from a 1992 TBI 350 to a 2005 LM7. Everything works perfectly, except the AC. Im using the factory AC system with a bracket and everything, but when the clutch cycles on at idle it majorly bogs down the engine. I know that the new engine's ECM doesnt hook up to my old AC system in any way though. So is it possible that I need to feed into the new ECM that the compressor is on? How would I go about doing this?

Thank you!

[96/chevy/pu]

It would help with the bogging down, as their are setting to jump up idle, when compressor is on. So you said your using 92 a/c system, does that include the R-4 compressor or are you using new style compressor?

[Minime168]

Its the r4 compressor. Thats really the only oroblem with it is the engine shudders when at idle because of the drag of the AC. How would I go about hooking this up?

[RedHeartbeat]

you could figure out how to wire up the PRNDL wiring so that when it thinks its in gear and it idles the engine up. Wire the compressor lead wire to the PRNDL signal lead that tells the PCM that its in gear and adjust the idle accordingly. I'm not sure if you need a ground signal, 5v or 12v going to the PCM for when it's supposed to be in gear. A little research could help figure this one out. I was about to tackle it myself when my 9.5" crapped the bed and I bought the 2007 GMT900.

[Minime168]

you could figure out how to wire up the PRNDL wiring so that when it thinks its in gear and it idles the engine up. Wire the compressor lead wire to the PRNDL signal lead that tells the PCM that its in gear and adjust the idle accordingly. I'm not sure if you need a ground signal, 5v or 12v going to the PCM for when it's supposed to be in gear. A little research could help figure this one out. I was about to tackle it myself when my 9.5" crapped the bed and I bought the 2007 GMT900.

Hm.. Never though about that route. Probably possible. Wouldnt it be simpler just to use the acrequest pin or something though? idk which pin to use. Someone has to have figured this out. Theres alot of people with the r4 compressor. Doesnt it drag your engine down too?

[RedHeartbeat]

my 92 and 93 both had issues when the a/c was running.

[Minime168]

my 92 and 93 both had issues when the a/c was running.

Like what issues? is it just the r4 compressor that sucks? i dont think it should be that much of a drag reguardless

[RedHeartbeat]

Mine was a Sanden 5 series compressor.

[Clayman]

im glad somebody brought this topic up! Im waiting on a tune from np and I gess I don't have any clue about how to fix this problem either. Ive read or somebody told me or something that u don't have to wire a signal to the pcm that it will sense the load and automatically idle up but I haven't got mine running yet because of the stupid antitheft system in the pcm. I would like to know how to go about resolving this issue tho...

[silverado_lover]

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