MA7008O

Hello there

Car is a 1991 C2 cabrio that runs perfectly, but recently I am experiencing some problems probably due to humidity on some connectors.

Problem: while running, all lights on the dash board illuminate as if the car has dies, but it still runs with no hesitation. The lights go on and off, on again, etc…. specially early in the morning after sleeping outside.

I am pretty sure it’s some connector with humidity (it has rain a lot lately), but it will be helpful to know where to start looking for,

Any inputs will be very much appreciated.

Sincerely,

ToreB

Search for "Christmas Tree Effect", there's plenty of threads on this topic.
You probably have a coil or plug wire with bad insulation, or there's a problem with the coils themselves. Moisture in the engine bay causes sparks, which in turn makes the Motronic Engine Control Unit to hiccup.
You could place the car in a dark place, and use a spray bottle with water to find the spot where it sparks. Start with the two wires from the coils to the distributors.
Cheers,
Tore

MA7008O

My mistake.

I thought the "Christmas Tree Effect" was only for C4.

Thanks,

-nick

Are your spark plug wires original?

MA7008O

Probably.

I bought the car when she was Young and never changed my self.

Las year, when doing a partial rebuilt, checked the cables and all of them seemed fine, but…..

Rocket Rob

No, it affects all 964 models. I'm with the others, I suspect its time for you to renew your coils and spark plug wires.

540964

MA7008O

Thanks you all for the responses.

One more question: can I still use the car before fixing she up or may I run into more troubles?

Thanks,

MA7008O

As an update with the issue:

• Changed the coils to 993 ones.
• Checked to spray water in the dark, but nothing happens.
• The problems still there.

A couple of questions:

• I saw over internet video on which dash lights stay on, but in my case, they blink. Is this the same or is it another issue?
• Are there any test I can do before got out there to get spares?

Thanks!!!

Rocket Rob

How old or new, are your distributor caps and rotors? Same for the spark plug wires? It still seems like you have a high voltage leak somewhere. The coils were the logical starting point.

MA7008O

Ddistributor caps and rotors are 1 year old.

Sspark plug wires are probably original.

Rocket Rob

I suspect the spark plug wires are your fault. 30 years is a long time for original wire insulation. If it were my car, I would replace them.

MA7008O

I finally replaced the ignition wires and the Christmas tree seems to have been switched off.


Thank you all for your help.

MA7008O

Well, to bad for me: Christmas tree comed up agian!!!!

What are my next steps?

Rocket Rob

How fresh are your distributor caps and rotors? Also, have you ever changed your coils? The christmas tree effect is caused by high voltage "leaks" in the ignition circuit. Its a process of elimination. Fortunately in this case, there are not too many parts to inspect or replace.