a/c fixed, now car stalls a lot

[Blackened302]

bought a new motorcraft compressor and accumulator today--a friend that's in the local mustang club we're in owns a shop, so he was nice enough to get me the parts at his cost and didn't charge me an arm & leg to get them in and the a/c going. blows cold as the 9th circle of hell now!!

anyhow, before this, back when the a/c worked for a while even, the car would stall when taking off from a stop (from a stop sign, or light, for example). it's doing the same thing now, too. at idle, it seems to slightly surge a bit--maybe a hundred or so rpm's. i checked the codes and all i got was the egr code.

what should i look for? could this be an electrical issue? too much draw from compressor, radio, lights, etc? maybe the IAC? weak alternator/battery?

thanks, gents. it's def nice to have the a/c back!

 

[Guero]

low idle?????

 

[HISSIN50]

Paul, is the EGR code something you're accustomed to? Otherwise, if EGR is present at idle, it can cause rough idling or stalling.

Do you note the idle bump up when the AC is turned on (with a hot motor)? If not, the IAC is worth checking. Surging with AC on is a sign of an IAC issue, but I'm surprised you didnt toss a cookie for it, were that the case.

Guero's point is valid, esp if the IAC isnt doing all that it should (actually raising the idle a little bit with AC on compared to AC off). Bumping idle might be a band-aid till you can fix it.

Good luck.

 

[Blackened302]

thanks, JT (and guero, hehehe).

the egr code i am accustomed to, yes. it won't surge when the a/c is off, runs pretty smoothly.

as soon as i turn the a/c on, though, there is def NOT an idle bump--in fact, there is a dip, surge, dip, surge, etc.

is there a way to test the IAC?

 

[HISSIN50]

thanks, JT (and guero, hehehe).

the egr code i am accustomed to, yes. it won't surge when the a/c is off, runs pretty smoothly.

as soon as i turn the a/c on, though, there is def NOT an idle bump--in fact, there is a dip, surge, dip, surge, etc.

is there a way to test the IAC?

Grady can probably tell you how to test it with high-techery . I cant remember if the 94-95 IAC is a fixed displacement unit or one that oscillates (like a fox's. On a fox, you use an oscilloscope to measure the square wave).

If you have access to a scanner (not reader) - something that can stream PID's, you can see the IAC %. That's how I got my idle dialed in how I wanted it. I could set it low and see how much duty cycle the puter was creeping into the IAC to get the idle where the puter thought it should be. I adjusted accordingly.

I think I let the cart get ahead of the horse there - removing and cleaning the IAC can be helpful. I'm sure you've seen it a zillion times, but here's an article about cleaning it. Cleaning it doesnt necessarily mean it will work though.

With your AC stuff, was any of the wiring bypassed? That could have gotten the puter out of the loop, so to speak.

Random thoughts. Good luck Paul.

 

[Blackened302]

thanks, JT.

no, none of the wiring was bypassed. all we did was put a new compressor and accumulator in. after a couple of whacks to the ccrm, though, the juice kicked in.

i'll have my buddy take a look at it w/ his scanner. by the time we finished up the a/c install he was late for church and the sun was already setting.

in the mean time, i'll clean the IAC and see if that helps. i remember that article--very nice write-up. thanks again, buddy.

 

[Methodical]

Yeah, I'd say clean the IAC 1st and see what happens or reset the computer (clear KAMs) and allow it to re-memorize (damn I'm starting to sound like Bush).