Porsche Repair: Porsche 968, porsche 944 automotive repair manual, automotive repair manual


Question
Sir, My 968 while idling or while I am reving it seems fine. But, when I try to drive it, it acts as if I am holding in the clutch. All the gears seem to work fine. My Car has 90,000 kms on it, and is european specs (I am military and live in Germany). The problem started while I was driving. I pulled over to check it out and could not see any problems. When I restarted the car it drove just fine. The next day when I started it, It started just fine. I let it warm up as I always do, and when I tried to drive the problem was back and this time is permanent. All fluids are fine, and I don't see any leaks. If you have any ideas I would greatly apreciate them.  

Answer
Richard,

Here's a list of things that could be at the root of your problem.  They're listed in most likely order:

1.  Digital Engine Electronics (DEE) system fault.
2.  Worn rotor, distributor cap, or wires.
3.  Faulty or incorrectly gapped spark plugs.
4.  Fuel injection system out of adjustment.
5.  Faulty coil.
6.  Brakes binding.
7.  Clutch slipping.
8.  Fuel filter clogged and/or impurities in the fuel system.
9.  Low or uneven cylinder head compression pressures.  

If you know that the car was recently tuned, then you can assume numbers 2, 8, and maybe 5 are not the problem.

Likewise with the condition of the brakes (6) and clutch (7)...if you know how long ago attention was paid to these, they may fall down to the bottom of the list.

If you're unsure about 2, 8, 5, 6, and 7 it would be wise to give the car a complete tune-up and brake check so you can eliminate these items from further consideration.  

My bet, based on your symptoms, is that number 1 is the problem.  If you're not familiar with the way the DEE works to control the fuel injection system, I'd invest some time in learning about this important function.

I'd recommend purchase of the Porsche 944 Automotive Repair Manual, published by Haynes.  It doesn't cover the 968 specifically, but all the components of the 944 were brought forward into the 968 with some updates along the way.  This manual ($20 or less) will give you a good sense of how the car is put together and the relationship between the DEE, its sensors, and the fuel injection system.

Even if you don't work on the car yourself, by learning more about the inner workings you'll be able to communicate more effectively with your mechanic...and vice versa.

As you get deeper into the problem I'd be happy to assist you any way I can.  Please don't hesitate to write back.  

Dave