broadzilla

Ok, time to help a female guys! 1984 944, was running great but battery fried up. Replaced battery and now the car tries to start, but seems to have a fuel delivery problem??? What is the diagnostic testing procedure for TPS's and MAS's??? Could it be something else??? HELP! I LOVE THIS CAR AND WANT IT TO RUN AGAIN!

sam

Not sure I would look at the MAS or TPS first. Do you have the correct fuel pressure? Too much (failed FPR) may prevent them from opening. I've heard it said that if you disconnect one of the fuel injectors, and the vehicle starts, that that is a sign of a failed FPR. I guess the extra current from the disconnected one allows the others to open based on demand.

I guess you should try that. There is a host of other basic tune-up type stuff you might consider.

Got a Voltmeter? Check the voltage on one of the injectors, ignition on, no start. Should have near battery voltage to ground.

I could go for a while, but I will yield to others.

Good Luck, let us know what it was.

Water944t

You might also check the wiring itself into the injectors.

I had to rewire all 4 of mine, the heat from the manifold had deteriorated the wires inside the boots. When the mechanic was changing the oil sending unit, he leaned on the wire harness, causing the wires to touch, just slightly, which caused an intermittant start failure.


I also have had the screw that retains the rotor, inside the cap, come off. The motor would turn over, I had spark, fuel, was going nuts. The damn rotor wasnt turning. Easy fix, once I found it.


You can test a TPS by unplugging it. The car should run in a default mode, slightly rich and a minor timing change. (Disclaimer: it works on Turbo cars, never tried it on a n/a.)

broadzilla

Thanks guys! Will try all your advice and let you know what happens. Here's to crossing everything - except wires LOL!

Lisa

rplencne

Though it's probably not the TPS or MAS, I'll offer a little info on the two. First, your 944 doesn't have a Mass Air sensor, but has an AFM (air flow meter). I guess you could say that it measures volume, but not mass. It's basically a door that opens further as more air is pulled thru it. It also has a temp sensor in it. Your can test it using an ohm meter by pulling off the harness that goes to it. The AFM does have "sections" so you will not see a continuous resistance change as you open/close the door.

For you're early 944, the TPS has 3 pins on it. One for closed throttle, one for wide open throttle, and a common pin. Again, you can pull off the harness and measure with an ohm meter.

If you need pin #'s, let me know. I don't have a factory manual handy but could look it up when I get home.

-Bob P.