Dave Cat

i have a '90 Base. Really odd series of events.

Problem: I can start the car, but it stalls when I am not giving it gas. It is drivable until I approach a stop and then stalls when I have to rely on the idle


Here is my odd backstory. Prior to this problem creeping up, I was trying to do an R12 to R-134 conversion on a leaky A/C/ I replaced most of the gaskets and pulled a vacuum. I tried to add the R-134 but could never get the compressor to kick in..... so I abandoned that little endeavor for another day........ put the bonnet back down and decided to take the car for a drive. It was fine for the first 3 miles but at the next start, i ran into the idle problems.

Reads of the forum point ot a multitude of potential problems - Im even scratching my head wondering if i bumped the TPS or IAC..... but ...


Question: Is it possible that some part of my A/C project has screwed up Vaccum that would support the idle?

aDigitalPhantom

Just for kicks can you disconnect the A/C compressor clutch and try again?

antfarmer2

or just hook up your freon and jump the low pressure switch to kick on your compressure to fill your freon. little bumps till it kicks by itself.

Cliff Harris

Usually you have to short out the low pressure switch to get the compressor to engage. Just unplug it and connect a jumper between the contacts in the connector.

I suggest a minimum idle adjustment. That will get your TPS where it should be and should stop your dying at idle:

https://www.corvetteforum.com/forums...post1570563689

Highly unlikely. They aren't really connected together in any way except for the vacuum that operates the HVAC doors inside the cabin.

HlhnEast

Start with the basics.

Dave Cat

thanks.....

I adjusted my idle. I was a little surprised to see the cap still covering the screw. I assumed that a car that age would have been tinkered with. Who knows. I'm not the original owner so perhaps the TB was replaced

I adjusted the idle a little high (500 ish) - I assume that's not a huge problem.

runs fine. took it for a spin.

thanks for the help

crowz

I'm glad its working ok but I bet you have vacuum leak somewhere. The lines crack easy with age and the rubber elbow joints they use on the end of the lines in places come out very easily. Can be a nightmare to find.

Its your call if you want to go hunting for the culprit but with the symptoms you listed the job you were doing to the car Id have to believe its a vacuum leak. A small one does exactly what you were having problems with.