Any ignition guys here? I need some help.

[steve930t]

I'm helping a friend with an 83 SC. The car runs fine when cold but when it gets warm it shuts itself off. The car has no spark until it cools down and then runs fine again. I ran it for a few minutes in the garage tonight, shut it off and let it sit for a minute and it wouldn't start. It has a Prematune box in place of the factory box. Could that be the problem? I had a spare coil so I tried that and it wasn't the problem. Has anyone run into something like this before?

[fred cook]

You probably guessed right when you asked about the Permatune box. If you can borrow another unit (preferably Bosch) to try, you will most likely find that the problem has gone away. If you have to buy another CDI unit, there are several after market units such as the MSD 6A or 6AL (sold by our host) that work well and cost much less than the Bosch unit.

[rattlsnak]

yep, classic symptom.

[steve930t]

Thanks guys. I've had good luck with MSD products so maybe I'll go that route.

[Rod80SC]

Had very similar problem last year. I ended up throwing parts at it to include complete MSD, rotor, wires, green wire. All with no luck. Found alot of slop in the rotor bushing on the distributor. Sent the dist to our host for overhaul. Upon receipt, stabbed it in and same problem. Great cold start, 5-7 minutes later she dies.
Talked to our host and he make good on a replacement dist. Started right up ran fine. Seems the problem was a faulty hall effect coil within the dist. A small broken wire that didnt show its self until warm. Apparently the dist ovhl guy missed it too.
Our host really came through on this one.
Best of Luck.

[HarryD]

I had a similar problem both with the Permatune in my car and a Spitfire many years ago.

If you think the permatune is overheating, do what I did to diagnose:

Carry some ice with you and the next time it cuts out, put a few cubes on the box. If it rights itself immediately, you have a commponent in the box going bad and you need to replace the permatune. Otherwise, it may be elsewhere.

[steve930t]

Originally posted by Rod80SC
Had very similar problem last year. I ended up throwing parts at it to include complete MSD, rotor, wires, green wire. All with no luck. Found alot of slop in the rotor bushing on the distributor. Sent the dist to our host for overhaul. Upon receipt, stabbed it in and same problem. Great cold start, 5-7 minutes later she dies.
Talked to our host and he make good on a replacement dist. Started right up ran fine. Seems the problem was a faulty hall effect coil within the dist. A small broken wire that didnt show its self until warm. Apparently the dist ovhl guy missed it too.
Our host really came through on this one.
Best of Luck.

Thanks for the info. I guess my next step is to borrow a CD box and try that first before I start throwing money at it.

[HawgRyder]

You can also try Cold Spray....its a product for electronics techs.
Same idea...spray on components you suspect of being "bad" when hot.
Instant tech in a can!!
Best part is....keep it in the glove compartment...no refrigeration needed.
Bob

[fred cook]

If you decide to install an MSD unit, send me a PM with your email address and I will send you some wiring info.

[steve930t]

Originally posted by fred cook
If you decide to install an MSD unit, send me a PM with your email address and I will send you some wiring info.

That would be great. I have an MSD set-up ready to go in but I'm waiting to borrow a CD unit from a friend to be sure it's the problem. If that's not the problem, where do I get a hall effect coil???

[Rod80SC]

here is a link to some of the discussions I had back when doing mine.
Symptoms of excessive distributor shaft end play ?
Warren the Early S Man is an electrical whiz. And always chimes in with great info. He included the magnetic pick-up part numbers. And there is another link inside if you want to take this on yourself.

[raj911]

hi all, i am new to the pelican forum. I have a 1983 911SC. I have been told that my original Bosch is on its last legs. Was thinking of installing a MSD unit, been hearing good things about it. Was wondering if anyone can tell me what coil I will need to use and if I will need to change my ignition wires as well, and do I need any other hardware. Any help from you chaps will be much appreciated.

[ischmitz]

Pelican has a rebuild service for BOSCH CDI units. I would try and get the Bosch box fixed before putting aftermarket stuff in there.

What exactly does "on its last legs" mean and how was this determined? Just curious.

Ingo

[raj911]

Hi Ingo, thanks. Actually this was told to me by my mechanic, I am working in Japan, and my car is being driven by my faince in Singapore. He was telling me to get one ready. My car has recently been put on the road after about 2 years of being in storage. I am expecting more of these niggly faults soon.

[ischmitz]

Funny you mention Japan. I am getting into Narita Monday afternoon for a quick 4-day visit. Where in Japan are you living?

Cheers,
Ingo

[raj911]

Great I am in Tokyo. Working and living in the Roppongi area. Let me know when you ll be around could meet up for a quick drink if youre free.

[HarryD]

Originally posted by raj911
hi all, i am new to the pelican forum. I have a 1983 911SC. I have been told that my original Bosch is on its last legs. Was thinking of installing a MSD unit, been hearing good things about it. Was wondering if anyone can tell me what coil I will need to use and if I will need to change my ignition wires as well, and do I need any other hardware. Any help from you chaps will be much appreciated.

THe MSD unit is a good replacement for the stock unit and offers some potential advantages due to the multiple sparks at the lower rpm ranges. However, it has a few issues that you will need to address:

-It is much larger than the Bosch Box and you will need to find a place to install it.
-You will need to get the matching coil (most use the MSD hi-vibration coil)
-You will need to modify the wiring to get the tach to work.

Several companies offer a rebuild service for the Bosch Box (if not Pelican, then I know Otto's and Zim's offer the service). If you feel comfortable, you can rebuild it yourself with the help of the articles published here (search for Bosch CDI), especially those by Early_S_man.

edited for spelling

[ischmitz]

Originally posted by raj911
Great I am in Tokyo. Working and living in the Roppongi area. Let me know when you ll be around could meet up for a quick drink if youre free.

sounds like a plan. My cell in Japan is 070-6423-8564. I see how my schedule works out. Ropongi sounds like danger zone....

[raj911]

Thanks for the advice Harry, I will be going home to Singapore for 2 weeks for a holiday and will be seeing my car for the first time in 5 months. Cant wait. I will probably decide then what I should do.

Ingo, sounds cool my cell is 080 3401 0677. Give me a call if you are free.

Cheers

Prithvi

[fred cook]

By rotating the rear window defrost relay 90 degrees there will be room to mount the MSD 6A or AL on the stock mounting bracket.



and by using flat male crimp on connectors, the MSD wired may be plugged directly into the Bosch CDI master plug.



Run the main power wire from the +12v terminal on the starter. Be certain to run thru a fuse for electrical protection. The original wiring cover will still mount in place an protect the electrical components.

Good luck with your project!