78SC won't start - ignition - Page 2

DaddyGlenn · DaddyGlenn's Garage

After a couple days driving around with a new ($50) pick up coil in the distributor thinking I solved the issue she died on me today. The engine cut out for about 3 seconds then refired.

Guess I'm back to troubleshooting. I suspect everything and will start over from the beginning.

Anyone know how often the engine wiring harness fails. My 30-year old harness has cracked wire insulation on several wires including the ones that attach to the coil and "green wire." And is there a decent substitute to the almost $500 dollar Porsche brand replacement harness?

T77911S · 01-29-2009, 09:47 AM

Ignition coil

DaddyGlenn · DaddyGlenn's Garage

Quote:

Originally Posted by T77911S

Ignition coil

That is what my gut has been screaming all along. But sometimes I like to ignore my gut.

So do I have to use a Permatune coil with my Permatune CD unit or can i opt for the less expensive Bosch coil?

T77911S · 01-30-2009, 04:29 AM

i would get rid of the perma-doom, perma-crap and go MSD.

it amazes me at how coils go bad on these cars. i use to work at an auto elecrtic shop, a long time ago, and i was having trouble with a car, i asked the guru there if it could be the coil, he said likely not, it is rare they go bad, maybe he did not work on a lot of porsches.

Daschundracer · 01-30-2009, 04:49 AM

Sorry to see your having trouble with the 78. If you need a helping hand, not much knowlegde about the car mind you, but just willing to help! Mark

DaddyGlenn · DaddyGlenn's Garage

T77 - I will go the MDS route once I am again gainfully employed. But for now, I just need to get my hands on a low cost Coil that will work.

Mark - Thanks for the offer. Know anyone with a spare coil lying around?

DaddyGlenn · DaddyGlenn's Garage

I took it for a trip this weekend, fully loaded with camping gear. 75 miles out on Friday and 75 miles back on Sunday.

It only died once on me and that was before it was fully up to operating temp. It fired right back up and didn't give me a lick of trouble after that.

T77911S · 02-03-2009, 05:19 AM

go to advance and get a blaster coil, there about $40

DaddyGlenn · DaddyGlenn's Garage

Brand new Blaster coil in place and still have the problem!

kodioneill · kodioneill's Garage

man, how frustrating.

ischmitz · ischmitz's Garage

Have you gone through the basics: Clean and re-seat connectors at the CD box, check for no frayed wires from the distributor (trigger signal), etc. If yes, it, sounds like you CDI box - see my previous post. These boxes do fail and your pattern is consistent with a box that latches up.

Ingo

toddu · 03-04-2009, 01:03 PM

Faulty fuel pump relay perhaps? (I admit, I haven't read all the thread details)

Todd

DaddyGlenn · DaddyGlenn's Garage

Quote:

Originally Posted by ischmitz

Have you gone through the basics: Clean and re-seat connectors at the CD box, check for no frayed wires from the distributor (trigger signal), etc. If yes, it, sounds like you CDI box - see my previous post. These boxes do fail and your pattern is consistent with a box that latches up.

Ingo

Ingo - This weekend I went through and double checked all the wires...again. I even unwrapped the wiring harness leg that goes to the CDI and found nothing. The problem seems to be accelerating it's frequency and I have to admit that it appears that you are correct and I am going to have to suck it up, spend the dollars and replace the box.

Todd - I have ruled out a fuel issue. This is definitely an electrical problem.

DaddyGlenn · DaddyGlenn's Garage

Finally got a new MSD installed Saturday morning and spent the rest of the day driving all around Pittsburgh. Not a lick of trouble and the car seems to start better, too. The wiring install is pretty ugly but I'll fix that when I have more time and access to a garage and the rest of my tools. For now, I hope I have finally solved it.

Thanks to everyone for their guidance.

rwsharp · 07-20-2011, 09:36 PM

Help. Does anyone know about connecting the green wire pigtail. The green wire I bought is only about 4 '', the wire on my car is much longer. I haven;t even found a connector yet. Is there a way to tap into the existing wire? I have searched this sight, but haven't seen anyone else having this problem. This is the only part listed for my 1979 911 SC.

Thanks, Ron.

DaddyGlenn · DaddyGlenn's Garage

Ron, welcome to the forum. The green wire is a co-axial wire and you probably don't want to try to splice it. Not sure which connector you cannot locate. Pictures would be helpful. I'm having trouble visualizing your situation.