1984 944. Project update and questions


Asked by Mar 01, 2015 at 10:45 AM about the 1984 Porsche 944 STD Hatchback

Question type: Maintenance & Repair

After changing the distributor cap, rotor, wires, plugs, fuel filter and oil. I drained the fuel
tank since I had no idea how long the car had been sitting and if the fuel was an ethanol
blend. The car started right up and was purring like a kitten. However, when it warmed up
the idle started surging. Also, when I turned on the lights they would dim and brighten.
Since this is really my first project and I'm nothing more then a backyard mechanic. Can
someone shed some light on what my issue or issues may be?

7 Answers


I don't think the two are related, other than a weak altinator might be dimming the lights at lower RPM's. Not sure, but I would believe that this is a pre-computer controlled car. Which would eliminate sensors or grounds. Sorry, I can't help, but want to comment on a beautiful car to restore, good luck.

1 out of 1 people think this is helpful.

Sounds like a bad or dirty IAC (Idle Air Control) valve. Rockauto.com has a listing for it. The lights flaring is most likely the result of the engine "hunting" (idle going up and down). Fix the hunting and the lights will stop flaring as well. HTH. -Jim


Thank Jim, I will try cleaning it this coming weekend. And update this thread on the progress.

1 out of 1 people think this is helpful.

You're welcome. Glad to help. Yes, please keep us posted. -Jim


The hunting is more likely caused by a vacuum leak some where, and maybe the idle air control valve, as JS indicated above. It's pretty inexpensive to buy the vacuum line tubing. The problem may lie under the intake manifold where many lines run. If you don't find the leak right away, then removing the intake and replacing those lines and gasket also might solve your issue. Just because of age, I'd replace all of them. Good Luck!

1 out of 1 people think this is helpful.

So I was able to stop the idle surging. The collar attached to the throttle body was loose and sucking air. I tightened the clap and presto no surging. But the lights still surge. What's weird is that it's a constant surge no matter now much I rev. it. Also the radiator fans don't come on. Any help would be great.


It always seems the big problems have simple fixes, like your loose hose clamp. Good find! The radiator fan switch is shot. It's mounted directly under the radiator hose on the drivers side, up high on the radiator.. It is probably two prong, as later models had a 3 prong switch. I think a 1 1/8" or 1 3/16" deep socket will get it out after removing the electrical connector. Be careful, the radiator tank is plastic, and there is not much room to move. Put teflon tape on the replacement switch. The surging sounds like maybe the alternator or even the battery is going. Advance auto parts will check them both for free. Fun cars to work on!

1 out of 1 people think this is helpful.

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