83 sc stalled while running fine
 

I hope someone can help. My 83 SC stalled while running fine, cruising in 5th gear at highway speeds. Car had been running for about half hour, and was at normal operating temp.

No hesitations whatsoever, it just died. I rolled the car to the side of the road and once stopped, I restarted it again. Ran just fine for about a minute and same thing again. This time I tried starting while rolling but it wouldnt catch. After I pulled over, tried starting. Definitely getting spark as it turns over, catches just a bit but popped and died. Did this for about 5-6 attempts over the course of about 20 minutes. In between restarts, I checked connections in engine bay, removed cap, checked and put back on, tapped permatune box. Nothing worked.

After about 20 minutes, restarted fine and ran great. Temp had gone down from the 1/3rd mark (normal operating temperature for this car) to about a quarter by then.

Car was tuned up about 500 miles / 1 month ago. Plug wires look good, cap, rotor new as are plugs. New fuel filter. Runs perfect.

I drove the car another 20 mins since the restart, and it drove great - just like usual. Haven't taken it for a long drive since then, afraid to. In 5K miles since i have owned it, never had a problem.

Help please?

Check your fuel pump relay. It may be getting old or coming loose at the connection.

Had a friend with the same problem leaving stranded a few times and then would restart after 20-30 minutes.

Replaced the Permatune with a Bosch CDI unit and it never happend again.

Relay looks good. The "red"cap popped off, and i can see the insides. Its moving just fine when i start the car. Contacts are clean and no corrosion whatsoever inside the relay, or any of the wires. Overall the car is original and none of the wiring has been tampered with in any way.

Now the car barely starts and stays extremely roughly idling only as I have my foot on the gas. Very loud knocking as well. If I don't do that, when i start it, it will roll over and maybe run a couple seconds before dying. It was doing this the first time it stalled and wouldn't start.

Currently the car is just luke warm, not hot at all.

CDI unit sounds like a good suggestion but very $$ for a trial.

Any other suggestions? Fuel Pump? Coil? I guess trial and error will be the best way to solve it, or taking it into a shop. I just hate the thought of having it towed 30-40Kms away.

What kind of knocking sound? Like a rod knock?:eek:

It sounds more like a "detonation" knock....if that makes sense..

Sounds like its starving for a spark to keep it running. Permatune malfunction may be the culprit. Bosch units are very pricey. Anyone here do a MSD replacement?

Car has 100K miles. It definitely seems like an electrical issue, that may possibly be creating a fuel issue.

BTW O2 sensor is also new 500miles ago (probably has nothing to do with this problem).

The car was running absolutely perfect for the last 5K miles since i have owned it, aside from needing a tune up and valve adjustment 500 miles ago.

Thanks for all the suggestions so far.

i had the same problem on my 77...replaced the permatune box with a Bosch CD box and the problem has never come back...hope it helps.

Sounds similar to my issue here:

http://forums.pelicanparts.com/porsche-911-technical-forum/452781-78sc-wont-start-ignition.html

If you have detonation and full shutdowns I think you CDI box is bad. The detonation is because the box starts to fire sparks at random times before dying completely.

The Bosch boxes can be tested and repaired for less than what it would cost to buy a new one. Contact me if you are interested.

Ingo

I currently do not have a Bosch box at all, so rebuilding one is not possible. Also, if i buy a new (rebuilt) one, I dont have a core.

All things point to CDI box for sure, so I was thinking of just replacing with another Permatune unit. Or change to MSD. Which way should I go?

DC Automotive has a used listed for $500

Pickup coil in your distributor.

If I replace Perma-tune with Bosch, will I need to change the coil too?

Find a used Bosch. A used one that works should be $200 or less. Get two. And yes, you should use the matching Bosch coil. MSD is second-place in my view. Permatune runs a distant last place.

Thanks Superman,

Where can I get a used Bosch CD unit for $200? I don't mind that price at all. DC Auto is $500. Coil change, no problem as it's expected. Under $100 is no big deal either.

ebay, pelican classifieds, samba
ull find one

WOW seams like you are spending money on an ignition box without a real diagnosis, just guessing.

...I am not sure about the permatune but the bosch boxes have a distinct whine with the ignition on , does yours have this , at least did it when the system was working ? zDoes it now ?

Did you try putting a plug in and seeing if you have a strong spark ?

have you taken the air filter out and lifted the air plate and listened to the fuel pump run ? it should cranl up immediately and be audible.

Have you tried adding a few litres of gas ?

A bad coil can give similar symptoms or as mentioned the pick up . What kind of coil is is ? anyone around you can trade with ?

I would do a little more research before ordering parts.

I finally got to the car last night, and replace the Red Fuel Pump relay. Car started absolutely fine. Unfortunately, when I put the old relay back in, it started fine too.

I dont think heat would have a large effect on the operation of a relay, therefore I will rule that out.

Whatever is not working, is intermittent, and the problem might be happening when the car is warm, rather than Cold.

I will have to wait until the problem happens again. Now I am scared to take it for a drive, knowing it will konk out at anytime.

Question: For those with Perma-tune problems in the past, is this similar to your experiences?

Thanks again for all the help and responses.

Yes!

I'm gonna replace Perma-tune with MSD today. 83 SC, do i need a Tach adaptor? Any other parts or hints i may need? I am fairly adept but i'm venturing into new territory....I will install MSD 6200 (no rev limiter) and MSD high vibration blaster coil.

Thanks for the tips