John Speake

Hi Dave,
Yes, I believe you can...

Daniel Dudley

That cap looks played. Do you know how old it is ? How about the wires ? If you don't know, then now is the time to replace them.

Always look at the simple things first. Most people who own 928s fail to replace the wires because they ''look good'' and are ''expensive''. The reality is that many 928s are running on the wires that came from the factory. The fact that this problem started in the rain says a lot. Many times a distributor cap will begin to leak electricity in an instant, creating a path for electrons that is etched into the plastic.

I have had three 928s, every one needed new wires, and every one had just come from a major service.

BTW, look at the electrodes on the inside of your caps. Do they look like they are crusty ? Sometimes you can flake the crust off and get the car to start. The crust does not conduct electricity. Use a screwdriver. LOL.

moon928

Dan- the caps, rotors and wires were all replaced back in 2001 and have about 25K on them now. It may be time to change them out. Any idea how long they should last? I cleaned the one cap tonight and didnt see any cracks at all- a few scrapes but nothing other than that. The electrodes have been scared a bit I thought at first they were crusty too but when looking at them a little closer it appears they have more of a groove on them.

I am determined to fix this and get back on the road. I appreciate everyones help.

moon928

I am back at it again and I think I have narrowed the problem down to the ignition module 0-227-100-124 as being the problem, but I could be wrong.

I bought and installed a new coil to replace the presumed dead coil on the right side (facing engine). I then cleaned the rotor and rechecked the cap for cracks before finally placing it back on the car. I fired her up and no change- the same problem running on 4 cyls.

I removed the cover and exposed the ignition modules and began testing them. I first unplugged the ignition module on the far right and the car did not start. It would crank but it would not fire. I then switched the modules and started the car again with only the left one attached. This time the car turned over and I had smoke coming from the tail pipe that was saturated with a heavy gas smell. Lastly I plugged in the other side and restarted the car and again I am only running on 4 cyls. Does anyone in the area have a spare module I can test?

Jim bailey - 928 International

Moon you just tested a "spare" ignition module and proved that only one of yours is working by making the problem move from one igniton system to the other. Too bad you did not try that sooner and save the money for the coil. John Speake tried to direct you to those units and when John speaks people should listen...

worf928

Mooney, when you replace the bad ignition module you must follow the WSM procedure and use heat sink paste (Radio Shack) on the interface between the module and the heat sink plate. If you are not buying two ignition modules it would be a good idea to refresh the paste on the old 'good' one (clean off old paste thoroughly first.)

worf928

Moony, I have two ignition modules you could use to test. Give me a call.

moon928

Dave- I neglected to do that. Now that I think of it there was nothing there I even cleaned the heat sink it a bit. Shouldnt I be getting a red or a green light on the test relay indicating I have an ignition problem?

Jim bailey - 928 International

You have no such relay...that began in 1989

worf928

You already put a new one in? Or you just swapped them?
If there was no paste residue between the individual modules and the rectangular heat sink plate then a) those were not the original modules b) that's probably why one failed and c) the other one has lost a lot of lifetime.

It's not a problem to run for a short while without the paste, but the modules will run hot and heat shortens their life. When I was researching my what-turned-out-to-be-a-Hall Sensor issue three years ago I ran across many anecdotes about these Bosch MOSFETS failing and mostly due to poor heat transfer.

moon928

I only swapped the modules out- right to left. Dont get me wrong there was some residue but it was crusty. It sounds like I am going to be replacing them very soon. I was researching the part number and it turns out that this unit is used in most P cars. I should be able to pick them up locally in the morning.

worf928

Ah hah! That 'crusty' stuff is whats left of the factory's heat sink paste. Scrape it all off carefully from all surfaces. Radio Sock sells way better paste (20 years later) for a dollar.