1972 Square Stalls When Hot Idle Issues

[twinkie72]

I have a 1972 fuel injected, automatic squareback. I have been having this issue on and off for about a year. The cars runs decent when cool. After driving it around town for a while (15-30 minutes) and after parking it for a few minutes, it will often stall when I come to a stop or change from reverse to drive. I took this in to the VW shop last summer to have it worked on and the mechanic only needed to adjust the idle. He also mentioned me needing a new VSP, whatever that is, but that he managed to adjust everything fine without it being replaced. I'd love to know how to do this adjustment myself since my wife is hollering at me suggesting we sell the car since it's "expensive to own." Can any of you point me to a resource or how-to video showing how to properly adjust the idle?

Thanks!
Dave

[KTPhil]

Never heard of any FI part called "VSP."

Poor idle on a FI automatic is often a combination of being a little out of tune, or vacuum leaks. I'd start by checking the point gap and ignition timing, and check all hoses connected to the intake system for leaks. It's a good idea to replace them every few years anyway. Then set the warm idle speed.

If this doesn't fix it, then you can move on to checking sensor/wiring resistances, and a deeper dive for vacuum leaks, like injector seals.

By the way, on an automatic, the idle speed in neutral is 950 rpm, higher than the 850 spec for the stickshift cars. This helps at stoplights.

[Donnie strickland]

[twinkie72]

Thanks. I'll check those suggestions out. I noticed something new today. The last two days when the car was warming up I noticed gas leaking out of the exhaust from the muffler. Is this a failed fuel pressure regulator or something else?

[KTPhil]

Well, you can add fuel pressure adjustment if you don't know it's right. Search for a simple gauge using a hardware store water pressure gauge-- accurate enough to eliminate this as a cause of your troubles.

If it is really raw gas, then you probably have a stuck injector-- either one of the four, or the cold start jet.

More likely it's just condensate with an exhaust or rich-gas smell.