TurboMike

Guy brought me a '83 944. He said it had a hard start problem, and would die then restart after it sat. I got the car and when it started it ran full rich. I mean I had to go wot just to keep it running. After about a 10-15 minute battle it cleared up and ran fine. I pulled it into the garage and the next day the same issue. I pulled the plugs and all the plugs were soaked. He's changed the relays, plugs, wires, cap,etc on his own. Any ideas?

Legoland951

Try the adjustment in the airflow meter. The best way is with an exhaust gas analyzer. I doubt all the injectors are stuck open all at one time.

TurboMike

I checked the AFM with a digital meter. It seems very linear. I tried unpluging it and starting, unpluged the TPS too. It drowns the plugs the first couple cranks. I checked the spark and it's good. Is there a way to pull codes? Any ideas at all? I've got a bunch of work to do on this car (clutch, belts, etc) but don't want ot start till it's running decent.

Mike 89 NA

Fuel Pressure Regulator? Easy test.

Mike

Legoland951

Being linear has nothing to do with how much spring tension on the flaps. It may be giving the wrong reading linearly due to bad baseline setting (telling the computer its getting much more air than its actually getting). I have to adjust these things all the time to pass the stringent calif smog. I am not sure whether its the spring getting weaker or what the cause is but they do need adjustment every once in a while. Pop the top off it and turn it while you are trying to start it. I had a bmw 323 with the exact same problem before. PM me and I can give you my phone number if you need me to walk you through it.

MHT

before you play with the calibration of the air flow meter, use a voltmeter to measure its output at idle, it should be in the neighbourhood of .5 volt. If you do tweak the spring, mark the starting point, so that you can put it back. There are no onboard diagnostics for that car. Have you checked fule pressure yet? If not then I would suggest doing so. When the regulators fail, it is not a subtile thing, it will peg your gauge. Check the coolant temp sensor, if it is open or there is an open circuit between the sensor and the ecu, it will dump fuel and foul the plugs. This would be the first thing I would do, given the symptoms you describe.

Good luck Mark T.

GMS

The first thing to do is check the fuel pressure. If out of spec replace the regulator and damper (on the fuel rail).

It's unlikely that the fuel mixture is out of adjustment on the AFM. From full rich to full there is not enough adjustment to make the spark plugs black.
Obviously, check all the systems, including distributor cap, roptor arm, plug wires etc.

TurboMike

I'll check those items tonight or probably tomorrow. When i say rich, I mean it floods the plugs and won't let it start. I then pull the plugs, clean them, purge the fuel from the cylinders and try again. Once it does start, I have to stay wide open and let the smoke roll After awhile it clears up and runs ok.