MPD47

AHHHHHHHHG. I've had the car back together for a week or two now, it runs but I've got some kind of vacuum/idle problem. I temporarily deleted the ISV as it was messing the idle up something terrible. Unfortunetly I've also got a vacuum leak I cant find, I'm gettin -6 on my gauge at idle. I'm sorry for the vague post I'm just fed up with working on the damn car. It wasnt so bad for the past 3 months when each day I got alittle done, but the past week or so I've been out there literally everyday and made NO progress. *sigh* I'm just a bit sick and tired of this and wanna get the car aligned and start driving it.

fast951

Do a pressure test on the intake system. This should pinpoint all leaks... Call if you need help or moral support

Ski

maybe this will help, from a stock configuration, delete and reroute items per you setup.

theedge

Yes, pressure test it. Get soapy water and dribble some on each connection, if it bubbles up from air coming out of the connection theres your leak.

Theres also the trick of spraying starter fluid as the car is running. Change in idle = leak. Ive never done this one, so I cant comment on it really.

Check over everything to make sure you didnt miss a crush washer or connection somewhere?

MPD47

I've used carb cleaner on all the connections and cant find the leak. I'm really quite fed up. Going to search around the local shops and see if someone has one of those smoke vac. testers they'll rent me. Ski, thanks for the chart, ive got it posted up on the wall of my barn along with the 944 grounds.

fast951

Weren't you able to get clean idle when you bypassed the ICV? Then when connected again, it didn't work? I think you might have a sticking ICV, elimiate it phusically from the system (take off hoses from manifold & IC pipe then plug them back).

David Floyd

Parts from local hardware store, valve stem on intercooler inlet, cap on tailpipe add 15psi and listen or squirt soapy water.

MPD47

Already did it

David... wait... you have to cap the tailpipe too? We may be able to now call me an idiot.

special tool

NO, you don't need to cap the tailpipe. The intake valves close.
Cap the front of the turbo and stick a compressor blowtip into the port between runners 2 & 3. Put a AA battery into this hose so it doesn't leak.
Cap the brake booster port with the rubber cap that should have been retrofitted to the air vent on the timing belt covers (fits perfectly)

J Chen

Hey Special,
Does this mean that you're pressurising the system through
the port between cylinder 2 & 3 of the intake manifold ?

special tool

Yeah, that's how I do it. Only takes a few minutes.

J Chen

Hi Special,
I'm running an MAF set-up with hard pipes. What I do is
I pressure test the intake right from the turbo inlet. Oh
just to be safe, I always use a regulator to set air pressure.

David Floyd

Maybe I am just lazy I can have the valve stem mounted on the intercooler in 30 seconds, no need to remove all the stuff to cap the turbo. Ok if the valves are closed I won't cap the tailpipe anymore, was just making sure with the cap.