Coil Mystery 78 911 SC

[SReppel]

I've been having intermittent no starts due to the coil on my SC. I've read all the posts and know about the problems with the Silver Bosch coils. My car had one like that when I first bought it and it failed after the first two years I owned the car.

I put a MSD Blaster 2 (Red) on it and it failed after about 1 year. I replaced it with a MSD High Vibration coil which is currently giving me problems.

Today I tried to start my 911 and it would not start. CDI Box wining but no spark to the plugs. So I figure it's the coil again. So I pulled the coil off my 944 (Stock coil) and put it on. My 911 fired right up.

I tested the MSD coil with my meter and it tested good. Hooked all the wires back up
an it started right up again.
This is the second time this year I've had this problem and I'm scratching my head trying to figure it out. The wiring and connections going to the coil are all good.

Has anyone else had this issue?

[smadsen]

I switched out my factory coil ('82 911) about 10 years and 50,000 miles ago to a Brazilian Bosch coil. It lasted about 2 months. My sense is Pelican bought a pallet of those things and continued to sell through. I discussed it with Wayne at some length and he was pretty decent, I forget what settlement we made, but the Brazilian coil was very expensive and clearly flawed in its' manufacture.

The ultimate fix for me was the MSD Blaster coil, I forget the number. It was made for off-road use. It's been mounted upside down like the original and preformed flawlessly for ten years

[SReppel]

That's the coil I have right now, the MSD Blaster High Vibration coil that is epoxy filled.

What I can't figure out is why after disconnecting the wires going to the MSD coil, hooking them up to another it will start. Reverse wire back to the one mounted in my car and it will then start when it wouldn't a few minutes before.

[timmy2]

Corroded, oxidized or loose connection is my guess.
R&R cleaned it up.
Or you have an internal intermittent that may come back.....

[toddetch]

I had an issue with an engine stutter in my '80 SC Targa that only happened when the engine was hot. It took a couple of months for my mechanic and me to chase it down, and what solved was one day the mechanic happened to have an '82 sitting next to mine and he swapped the CDI boxes - turns out that completely solved it. The mechanic said it was a CDI failure mode that he had never seen before. I spent the extra to replace the CDI with the Classic Retrofit CDI (available on Pelican) and I also replaced the coil with the same one Johnny at Classic Retrofit sells as well (not available on Pelican - but PM if you're interested). Been using both for several months and they're working like charms.

[Flojo]

I run the MSD 8222 as well... and just love it! No issues!

Though, at first, with the overhauled Bosch CDI (HKZ) it had som "burps" here and there... swapped it against a newinbox silver Permatune and now it runs strong and flawless ever since the last 3 years.

to make it look kinda OEM black Bosch, I stripped its MSD-sticker and added the Bosch decals

[SReppel]

Thanks for the info.
I'm going to remove the CDI box and check all the connections and wiring first
then see what happens before buying a replacement for it.
I kind of suspected that the CDI may be going bad but the coil swapping thing had me stumped.
I'm going to discuss the problem with a friend of mine who has a local shop and worked for Porsche for many years.

[Flojo]

and check the green wire!
it comes from the CDI and goes to the distributor.
can be a culprit as well

[SReppel]

Yea the little green wire got me already about 2 years ago, Looks like a short piece of green wire but not so!!