joshrlc

My car has been having a hard time starting after not using the car for some time. Well, it finally gave up. I'm getting fuel (I can smell it in the exhaust pipe) to the cylinders. I am having issues with spark. The spark seems very weak. I pulled the ignition wire off the coil and it sparks but it's not as strong as I'd expect. When I connect it up to the distributor cap and pull a plug, I can barely get a spark.

Is this the sign of a bad ground? Or is it a bad coil? Bad spark plug gap?

I can't get the car to fire at all. Prior to this the car was stumbling at low rpms but would be fine after that. Not sure if this is related.

Thanks for your help.

Josh

Steve Weiner-Rennsport Systems

Hi Josh,

I think it would helpful if you listed what year & model your car is as thats the main prerequisite for troubleshooting.

joshrlc

Yes, that might help. My bad.

It's a 1974 911 with a 1976 motor. So for all intensive purposes, a 1976.

Update: I pulled plugs on passenger side bank and they are definitely getting old. I'll be replacing them. Also, I pulled the distributor cap and cleaned things up a bit for better contacts. When I pull a plug and ground it while firing the engine, the spark is weak. Not a real strong spark.

I pulled the ignition wire from the coil off of the distributor cap and ground it while cranking. I have to have the wire within 1 mm to get the spark to jump. Again, very weak in my opinion.

My car doesn't seem to have much cranking power so I boosted it with a battery charger and that only helps crank things over for a bit. For that I've swapped out the battery, tried jumping it, removed and cleaned the grounds (negative terminal at the battery and the grounds on the coil) and still nothing.

Is this a sure sign that the Capacitive Discharge Unit is going bad or has gone bad? This seems like a spendy fix so I don't want to go down there road unless it's going to correct my issues.

Any advice would be appreciated.

theiceman

Sounds like cdi. Do you have original Bosch box or an aftermarket permadoom. ? Also keep in mind it could be the coil. There are places that will exchange your cdi box for about 350 or so. Buddy just got one and it worked great.

joshrlc

Well, after trying everything (plugs, wires, coil, distributor cap, rotor, points) I finally replaced the CDI. Vroom. Started right up. I replaced the other items because they needed to be replaced anyway (except the coil) and was hoping I wouldn't have to bite the speedy bullet. At least she's running. That's the important part. Thank you for your help!

theiceman

good for you
congrats on your fix