dkarten

car has 332k, had been having cold start problems, replaced csv, filter, 02 sensor, plugs, wires, cap & rotor, checked all sensors, improved after all these replaced but still not happy when cold, would drop idle & almost stall, then come back, fine when warm, yesterday stopped running after 20 minute drive & would not restart, finally unplugged differential pressure regulator & car started & ran enough to get home, tried installing brand new DPR from my 1987 5K, no change, will not run, for some reason I cannot adjust co mixture screw, it is frozen, I am familiar with adjusting co on my 5K, the 100 adjustment screw will not move, I have airflow meter & Fuel distributor from parts car & am considering replacing those, any suggestions?

dkarten

when I started it this morning wih a cold engine it started & idled fine until it started warming up & then stalled, which makes me think it is a temp sensor issue, will check that again with meter altho I had checked it & it's wiring before

audi_marv

Was it the Fuel filter that you replaced ? Fuel Pump Relay check out ok ?

Check your Ignition/Speed sensors, as the magnetic signal may be failing as the car warms up. See if you can pull any codes.

Check for vacuum leaks at throttle plate hose(michelin man hose), etc.

Also check/clean your Idle Valve. You can spray the throttle cleaner on your idle adjustment screw to clear out any frozen gunk in the opening. Not sure, but i thought the idle screw on non-turbo's should be screwed
in all the way.

Another problem may be your warm up regulator...if your car has one. Tiny screens at the fuel line connectors could be clogged, or the bi-metallic heating strip may be malfunctioning.

Always a good idea to run Seafoam in your gas to clean and remove water from the system.

dkarten

fuel filter replaced, will check FP relay, will try to check ign/speed sensors too, no vacuum leaks, idle screw all the way in as it should be, ISV OK, no WUR on non turbo,

dkarten

wouldn't this mean it is a fuel injection related issue?

audi_marv

Sounds fuel related, but could also be Ground to ECU issue, Coil issue, MultiFunction temp sensor, Stuck Air Plate/Throttle Plate, or the FP Relay. Have you tried using Starter Spray when the car won't fire ?

Any luck with pulling codes ? Hopefully its not a Hall Sensor problem.

dkarten

checked ground, tried spare coil/ignition, checked air plate, all OK, when I checked fuel pump relay I put fuse in to pull codes but this car had it's instrument panel changed & that light in the new IP is not coming on & have not had time to pull IP to see why BUT... CAR RAN ONCE I PUT FUSE IN FP RELAY??? when I removed fuse it still ran & now seems fine, I will replace FP relay is this what happens when a FP relay fails?

audi_marv

FP relay may cause multiple symptoms, and could be your problem if you haven't changed it in a while. Also check the underneath connections for the relay at the fuse box itself. Fuse box sees a lot of water, so a little electrical contact cleaner couldn't hurt.

If problem appears again, look to fuel pump itself, or wiring from fp relay to fuel pump.

dkarten

thanks Marv, appreciate your input, now to work on 5K, will post on that soon