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I have a 5.3 DBC with a 550/550 cam and Vintage Air. The truck runs great all around until I turn the AC on. No problems in Park or when cruising, but when coming to a stop with the compressor engaged, it drops down to 400ish RPMs, then jumps to 1200 or occasionally stalls. I'm new to HPtuners, and can't figure this out searching through the forum. Thanks for any help!Attachment 160741
Without a log it is impossible to tell, but I am going to guess that the pcm is not even wired to know when the AC kicks on. Honestly, it looks like you got a quickie half assed tune from someone, and then someone has been trying to change a bunch of AC on values without understanding the underlying issues with the tune. Also, when describing a cam for tuning purposes, the duration is far more important than lift numbers.
You can get it to work without a A/C wired to the ECM. It's harder but not impossible.
Most issues like this are actually fueling or timing issues and the extra load from the AC just puts it over the edge.
PS you primary and secondary VE tables need to match.
Oh come on. You have to know that is the ole 3/4 race cam.Quote:
Originally Posted by gametech
Quote:
Originally Posted by dmuhn
Put it back to stock and then start to tune it correclty.Quote:
Originally Posted by gametech
ask questions on how, and post up your tune and log.
Saying you have a 550/550 cam means zero to anyone. post a link to the actual cam so we can see the specs.
Its a swap, so you really need to post everything about the entire vehicle, it all matters to the tune.
And every time post the tune and the datalog, or else its just like pissin into the wind..
Funny side story. Email customer sends me a screen shot of the cam in his LS. It's a Summit cam, it says LS in the title but the picture in the Summit ad is clearly a SBC cam with a distributor gear and fuel pump lobe. I said if that's the cam in your motor, you got real problems LOL
Carry on......
Thats going to have quite the cam bearing clearances..