Starter or ignition switch or both?
 

Car is an '83 SC and I'm chasing a seemingly common hot start issue. Starts up strong when cold, but once warmed up, it's a crapshoot. Sometimes I'll turn the key and nothing will happen (but accessories/lights work). Other times it'll crank but feels pretty weak (I have nothing to compare against tho, my first Porsche).

Already replaced the fuel filter and accumulator and it didn't remedy the issue. So about to order a starter (current unit is a rebuilt unit installed ~15 years ago), but have also read that it could be the ignition switch which I believe is original. I figure replacing 35 year old parts can't hurt, but if it doesn't make sense I won't bother. Done a bit of searching and reading and it doesn't look like there's an easy answer, but anything obvious I might be missing?

There is a ground strap that goes to the transmission. It's connection points might need cleaning and the strap may need to be replaced. I had to replace the one on mine a few years ago due to similar symptoms.

make sure all your main connections are clean starting at the battery.

those parts wont help a slow/no cranking engine.

I would have the old one rebuilt if they can put a new solenoid on it.

The factory style starter is prone to heat soaking. You don't have your location your profile. For my 85 it would be fine for local driving and even many autocrosses. Only on long road trips it would hat soak and even with every component working, it would not budge when the key was turned. It would push start with ease if I had some help or a hill.

I finaly replaced it with a high torque starter that is several pounds lighter, and has been flawless. It sounds different when cranking, but it ALWAYS cranks.

Agree with the high torque starter. That fixed my issue on my 83 SC.

Agree with the others.....put a high torque in.
I rebuilt my Bosch starter and it worked for a while but would still refuse to start every now and then.
It's been fine since i put the high torque in.

There’used to be a cheap unit that could solve your problem. I bought it and it worked.

However, skip with this band-aid and upgrade to a HT starter.

Thanks all, ordered the WOSP high torque starter and will clean up all the connections down there.

It takes a while to get used to the "funny" sound of a non Bosch starter. But it is VERY comforting to to hear that magical sound of the stater actually starting the engine. Especially is remote places.

Welp, new hi-torque starter is in, as well as a new ground strap. Car starts great when cold, much stronger than before.

That said, still have a hot start issue. Looks like I have some CIS shenanigans to deal with. The previous owner replaced the CDI box, spark plugs, fuel pump and fuel filter 5k miles ago, less than 2 years ago. I always said I wouldn't chase CIS problems and just get EFI if it came down to it, but was hoping to avoid that route for awhile. Any other ideas for hot start issues on an otherwise stock '83 SC?

Worth a try: how is the ignition switch? Is it pretty tight or loose? Have you tried rocking the key (or pushing inward) while trying to start?

New starter works fine hot or cold according to his last post?
Just doesn’t want to start while cranking when hot is what I get from it.


Shamrock,
Check valve on the fuel pump ok?
Residual pressure is often the CIS culprit with hot restart problems.
You already replaced the accumulator.
Time to throw a set of pressure gauges on it and see what is going on.
Swapping parts without testing is not the best approach/answer....

Yeah, I definitely don't like throwing parts at problems if I can help it, but since I don't have any records of the starter and accumulator ever being replaced, I thought it couldn't hurt.

I'm going to pull the check valve and see what kind of shape it's in. But looks like I need to swing for some pressure gauges.

Yeah I was under the impression your starter was having a hard time turning the engine over after it ran for awhile. Are you saying it cranks fine but it is difficult to start once warm? If so then yeah, I agree you need a pressure gauge to go from here.

Where are you located? If local, I could let you borrow my gauge!

The starter was a rebuild installed at least 20 years ago from all the records I can gather, and was always weak with me, so I'm glad the cranking power is better.

I'm in Spokane, and luckily have a great shop nearby and might have them do a pressure test. Then again, I guess if I'm gonna keep the CIS, I should get some gauges anyways.

You are correct. If you’re going to keep it, buy the tool.

I had the same problem with my 83SC and after changing the starter solenoid, complete starter, trans ground strap and ignition switch
,twice someone here suggested changing the original ground strap from the battery, I did and I haven't had a starting problem since.

Lorne M.

Same here, the HT starter fixed the problem on my ‘82, although I did swap out the ignition switch as well.

Well, it looks like he has other issues.


Op,
I agree with you about replacing the old starter. That money was well spent.

Before diagnosing your fuel system, have you sanded and cleaned all connections (battery post/terminals, battery connections points, ground Points, fuses in the trunk, fuses in the frunk, ignition coils, etc.).

Cleaning is free. I would do this before jumping into the CIS. Or while waiting for your tool to arrive