yesitsjulian

Hi all,
I’m working to revive a 86’ Porsche 928 s and finally got it running after cleaning of the ICV and MAF. I had to stay on the gas to keep it alive or to turn over initially. While Turing the key I had to feather the gas to get it going but if I revved it too high in park, it dies. I replaced the ICV after with an after market from 928srus and continued having the issue. Pulled over in my neighborhood while doing some test laps, put it in park and it stalled. Struggled using original method to get it to start. Would run with foot on the pedal but die as soon as I let off. Left it for an hour and came back to try again and it kept idle so I got her back home as quick as I could. What could be causing this?

PC-85-928S

Has the car ever had the intake off for a refresh?
Did you remove the intake to access ICV for cleaning?
How did you clean it?

The Forgotten On

That sounds like a massive vacuum leak somewhere. My 89 (similar system) had an issue like that that turned out to be the hoses under the intake cracking from age.

If the intake has not be resealed it is advisable to do so ASAP.

davek9

May want to consider having the MAF rebuilt, also check your Fuel pressure at the fuel rail, should be around 35 lbs at idle.
Blake's advice is spot on too, the 85/86 intakes have a lot of possible places to not re-assemble correctly

yesitsjulian

I took off the side pieces of the intake but nothing bolted to the engine. I had to pull the air filter housing (attached to MAF) to get in where the ICV is. I replaced the throttle body to intake boot and all 10 of the intake boots