No A/C = Less vibration / studdering at idle?
 

I noticed this weekend that since its cool enough in Houston now to not need the A/C running, the car doesn't have that annoying studder every few seconds where you can really feel the car shake. It seems that the A/C compressor contributes to the problem for me. I can still feel a slight more continous vibration at idle, but not the studder sensation.

Any idea how we can use this info to fix the problem while the car is running? I'm a little confused why the A/C would matter when I know the issue is the PCM trying to run the car at a ridiculously lean AFR at idle. Someone stated the the studder is the fuel injectors cutting on and off trying to fight to keep that real lean idle setting, which I believe given my megasquirt tuning experience. Does the A/C just put more strain on the engine at idle than it would when driving?

AC compressor is a significant increase in load, especially at idle. A lot of cars will "sag" at idle when the compressor kicks in.

If yours is engaging that frequently (every few seconds) you may need the updated AC amplifier, or follow the "reprogram" instructions that have been reposted elsewhere, which result in longer duty cycles.

I have noticed this as well as the idle just doesn't seem quite as smooth now with the R flash (recall) at anytime.

One of the things I have notice about the R Flash is that it COMPLETELY overcomes the problem of engine vibrations when the AC kicks in and out at idle.

I was feeling it before and now it has magically dissapeared!

Regards

jird20

He has the R flash.

If you go to the link below and look at the cutaway you can see why the AC compressor shakes the Sh** out of the car it has damndible pistons.

http://www.autoswalk.com/accomfun.html