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Need Help Starting '82 928


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I have a 1982 – 928 Porsche. My wife and I took it for a leisurely tour around our neighborhood. I put the car in the garage and did not start it again for two or three weeks. The fuel level was low, but the fuel warning lamp was not on.

The other day I needed to move the Porsche. When I tried to start it, after several seconds of cranking, I released the key, and the engine backfired. When I tried to start the engine again, it would start to fire, but would only fire while the ignition switch was in the start position. Once the switch was released, the engine would not run.

I changed the fuel filer, and checked the operation of the fuel pump by jumping the fuel pump relay terminals. I also checked the spark plugs for excess fuel, but they were dry. Then I removed the distributor cap and found everything pretty clean.

Since the engine tries to start (fire) when cranking, I assume it has spark. And since it does fire while cranking I again assume that it is getting some fuel. I wonder if when the engine first backfired, that perhaps the camshaft timing belt went out of time. Or back in the olden days, the same symptoms would show up if the ignition switch failed. Do you have any suggestions?

Best Regards,

Mike Rose (Old guy from Conroe, TX)

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Been ages so I can't remember if your model year has CIS injection. If it does during cranking it could be trying to fire off the cold start injector. I suggest you first check fuel pump pressure. It would also be wise to add a few liters of fuel as you can't always trust the gauge.

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I've checked out the CIS Injector, and found that it was only produced on MY 1987-1988 928s. I still cannot get the engine to run. I haven't had time to check the camshaft timing. Would that be the next thing I should check?


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Fuel pressure test port is located on the left fuel rail near the intake runner. I believe the operating pressure is 35-40 PSI and residule pressure should hold 15 PSI after 20 minutes. Sorry this is all from memory and I can't recall the pump volume specs.

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Fuel pressure test port is located on the left fuel rail near the intake runner. I believe the operating pressure is 35-40 PSI and residule pressure should hold 15 PSI after 20 minutes. Sorry this is all from memory and I can't recall the pump volume specs.

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  • 2 weeks later...

First off, my heart goes out to you... these 928's are fun until they display gremlins! If it were me in your shoes, try to keeo the initial checks simple. Remember, a car need sthree things to run... gas, spark and air. Seems you have checked the gas issue but you say the plugs are dry? I would pull a plug, dry it well, and reinstall. Try starting. Then pull the same plug and see if wet. If so, you have fuel.... next, check the spark. Pull a plug and in a dark environment, install the plug boot and hold the boot and plug with an insulating gripper up to the engine block (I usually use a piece of wood cracked in half)... with someone cracking the engine, do you get spark? If yes, then it is a different issue. I would then expand into the cold start injector (pull and clean/or replace)... then I might try the timing, fuel pressure, etc. Another idea is try some starter fluid. I'm not a fan so use it sparingly. See if it starts with a shot or two... if so, you have spark and its a fuel issue. Hope this helps... Tim

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Thanks Tim,

I did pull the air cleaner and pour a small amount of fuel in the intake. The engine started until it ran out of gas in the manifold. So, I believe I have a fuel delivery problem. I also, installed a new fuel injection relay thinking that may be the problem. No luck. Still won't start. Is there a way to verify if the "brain" is the culprit?


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