Car stalls when stopping if heat/ac is on.

[ForcedSHO]

Well I'm still having an issue with the car. It's been ongoing since I got it.

If the AC/Heat is on and I pull up to a stop sign/red light the car will shut off. Now it doesn't do it all the time though it's been more towards the cold weather/rain.

Replaced:
Alternator
Battery

It happened today and it was raining pretty hard. I'm going to check the codes tomorrow and see if anything comes up. I've been looking around here and it doesn't seem like anything I can figure out. Belt is very tight and nothing is loose by the alternator. Maybe grounds should be checked need a diagram to see where they all are.

Thanks,
Ed

 

[sperold]

What is your RPM at an idle?

 

[stangeater]

Sounds like your AC compressor is putting a strain on things. Does the ac work?

 

[St Louis SHO]

Compressor locking up?

 

[projectSHO89]

IAC lazy?

 

[ForcedSHO]

The AC compressor was fixed when I got the car. AC and heat work great while driving.

My rpm at idle is at 800-900rpm. When the defroster is turned on or the system kicks on you see the drop right away to 100rpm and it will shut off.

I have no problem starting the car in the morning to let it warm up and have the defroster/radio/headlights on and has no issue. Seems to happen when the car warms up.

 

[CWhalenSHO]

Had the same problem when I had my 5.0 Mustang. Idled fine when cold, but when it got to operating temp, it would do the same thing. Sounds like the IAC to me.

They aren't too expensive. I believe they are the same part as the Mustang...well, they appear the same. I'm sure someone will correct me if I'm wrong about them being the exact same part. Looks are deceiving with car parts.

That's my 2 cents. Hope it helps you out. :wave:

 

[jmpSHO]

I had an alternator in my SHO that wouldn't charge once it got hot.

 

[rubydist]

Before you change any parts, I would do the idle reset procedure. That will ensure that the idle speeds are where they should be. If that doesn't do it, then the iac is the most likely candidate, imho.

 

[ForcedSHO]

Ran fine this morning. Turned AC/Heat on at the stop light and no issue or fluctuation with the rpm gauge.

I will do the idle reset procedure after work and run the codes too.

Thanks

 

[mrecoolgar]

My first guess is the idle air valve.

 

[sdpatt]

Before you change any parts, I would do the idle reset procedure. That will ensure that the idle speeds are where they should be. If that doesn't do it, then the iac is the most likely candidate, imho.

Well put. Search "idle reset procedure."

 

[ForcedSHO]

Will do the reset today. Will let you know.

 

[ForcedSHO]

Ran the test for codes and got 111. System Ok
Did the idle reset and that all worked out.

Driving about 2 minutes this morning and I pull up to the light. Had defroster on and was changing stations on the radio. Dead. Go to crank and it just wants to turn over. Give it a few seconds and then crank it over and give it gas and she starts up and runs fine.

This is the first time it would crank over after dying.

Still the IAC?

 

[ForcedSHO]

Alright cleaned out the IAC with some intake cleaner. Put on a new gasket for $2.68 and the everything seems to be running fine now.

Thanks again guys!