I am actually a mechanic but this would be the first porsche i have ever worked on, so dont hold it against me. I have tested almost every circuit that goes into the computer and everything seems to be working, the engine cranks but will not start, it does not have any injecter pulse, no spark, and no fuel pump operation. I have already tried a new computer and i am still getting the same issues. I have also tested the "Digital Motor Electronics" relay and it is working the way it should be, the computer is getting all of its power and grounds, i checked everything with an ohm meter. The crank sensor is sending about 4 volts to the computer while cranking and from what i have read that should be more than enough. As far as the fuel pump operation goes I can ground the the wire that controls the fuel pump relay right at the computer and it comes on and works fine. I was thinking about the security maybe disabling the engine but i have no way to test the security, we do not have the equipment at the shop to test it. I have also noticed that every once in a while the battery will go dead over night, I have not really got into that problem too much, I am more fixated on getting it running. I have talked to a few people about this and nobody seems to know a whole lot about porsches, any ideas would be very helpfull. thanks
I don't know much about Porsches either, but the only thing I can think of is the Immobilizer system not recognizing the key and not letting the car start. I don't know if Porsche even had that in 92. But if the key is thicker/bigger then the regular keys, then it has Immobilizer. Then I would look for instructions on how to program the key to the car (that's assuming the system is working fine and it's just the key that's new to the car or the system's memory was somehow cleared).
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My 986 does the same thing. I realized that opening the door made the squeaking stop. Assuming it was cause by the the door rubbing against the jam, I tried to quiet it using tape (as a buffer) , silicone spray, grease, etc. Sorry to say, no luck yet. I'm thinking of just removing the door. Well, actually both doors to keep it symmetrical. Let me know if your squeak is caused by the same thing and if you find a solution which is better than mine.
could be a number of possible faults.1/crank sensor not working when hot,trace this and pour cold water on it(dont do this if it is not by crank pulley as water isnt good for modules etc) and retry.2/sparkplugs worn,but usually they would fault more on cold start.3/fuel pump cuts out when run,try wacking tank from underneath and retry.though I would concentrate on nil spark caused by a faulty ignition module or crank sensor. Next time it fails to start.pull off a sparkplug lead,make a quick test plug with an old(but working)sparkplug.pull the side wire away from the center electrode 5mm and insert into plug lead.earth ground the plug on its thread against metal on the engine.crank and check for spark visually,don't be tempted to hold the plug while cranking.if nil spark we will have to test further which is faulty sensor.if it sparks ok we will need to test for fuel. testing for fuel is easy. when it fails,unclip air filter housing,while engine is being cranked,spray an aerosol based carburettor cleaner into air duct to engine,it should start and run while spraying and stop when you stop spraying if fuel delivery is the fault.fuel pump will then need testing/replacing. be careful not to spray onto ignition or any areas of spark
If you think there is fuel pressure just because the fuel pump kicks in, you might not actually have pressure. The fuel pressure regulator could be shot which would cause the fuel to go right through the fuel rail and back into the tank. So make sure you use an actual fuel pressure gauge to test that and rule out the pressure regulator...just had to make sure you did that.
If you do in fact have fuel pressure, spark, and compression, then the issue is either your timing or that the fuel is not getting inside cylinder. Timing fix is obvious, the issue with your fuel could be clogged injectors, bad injectors, or the injectors are just not getting the signal to fire. The latter is the most likely. Use a mechanics stethescope and hold it to one of the injectors and listen for a clicking sound when your cranking the engine over. You can pick one up at harbor freight or sears. You could also take a screwdriver and hold it against the injector and press your ear against the handle. However, if the engine shakes while you crank it you might have a very bruised ear...try explaining that one to your friends. If the injectors are not firing, the resistor pack is probably bad. The resistor pack is that thing on the drivers side of the engine compartment with the heat sink on it. Pick up a new one from a junk yard if you want to save a few bucks. That should fix your problem though.
Start by squirting a little fuel into the throttle body and then crank it and see if it fires up .. if so its a fuel problem if not its going to be something in the electrical. holler if you need more thanks Jerry