Igaffz

Hi guys, first post in this section but I've posted in the 928 and 964 forums over the last few years.
I'm the new owner of a 1985 square dash 944 lux, the car has sat for four years in a barn but had the following fault befor it was laid up.
The car starts instantly and idles great for maybe ten seconds then starts to get bogged down, the revs fall to 500 and it will eventually stall. If I Rev the engine when the revs fall back down the car will stall also. If I keep the revs up for a minuite or two till warm air starts to flow from the heater it idles and revs perfect.
So far I've drained the old fuel and replaced the fuel filter, changed the plugs (the old ones were jet black) changed the air filter, the oil and oil filter and fitted a new coolant temp sensor. I've also sprayed easy start on the intake pipes then removed the intake and checked for leaks, then cleaned the ISV in petrol.
None of the above has made any difference!
I have an airflow meter but it's of an f reg 2.7, the part number is slightly different, could I try this?
Any other suggestions?

Many thanks
Ian

V2Rocket

First thought is to check the adjustment of the throttle position switch and the throttle stop screw.
Maybe the blade is too far open for a decent cold idle but is masked when warm.

mytrplseven

There's a blue capped DME temperature sensor at the front of the engine near the water neck. They're cheap and if the connector is ok, I'd recommend you replace it. You won't have to drain any coolant and only a bit leaks out in the process.

951Dreams

+1 if that's not the sensor you already replaced.

Igaffz

Yes I've changed that, we refer to that as a coolant temp sensor, unfortunately it made no difference!

Going to check the throttle stop and see what it idles at hot.

Ian

odonnell

The extra AFM you have won't work plug-and-play, it would run like garbage. How are the vacuum lines?

Also you may want to pull the aux. air valve (what you call the ISV, it's under the manifold) and test it to make sure it's closing ok and over a reasonable timeframe. You can visually see it working, just put 12v across the 2 pins.

Igaffz

I think I'll remove the manifold again and double check for leaks, I'll test the ISV while I'm in there, gutted the coolant temp switch didn't fix it I was sure it would!

Cheers for the help.

Ian

konakat

Sounds like vacuum leak to me. Idle control valve wouldn't cause severe issues like this, just a high hot idle or low cold idle. You can also try unplugging the throttle position sensor to see if that helps.

Igaffz

Cheers for the help, I'm going to try the above suggestions over the weekend.
Just in case the above suggestions don't cure the problem could the fuel damper or pressure regulator cause the symptoms above?

Cheers
Ian

konakat

I doubt it. Fueling issues would continue beyond cold start.

Igaffz

I think I've fixed the cold idle problem. When cold the car was ticking over at 500-600 revs until it eventually stalled. If I reverted it it would also stall, after a couple of minuites it would tick over ok but at only about 600 revs, I feathered the accelerator for 10-15 minutes until the car was nice and hot then adjusted the idle at the throttle body till it idles at 900. I left it to cool for a couple of hours then tried starting her and she idled perfectly at 900 without and stumbling or roughness! I think she's fixed!
Now I need mounts as mine are toast!

Many thanks
Ian