safulop

For the past while, my car won't start occasionally. Turn the key, car turns on, turn it over to Start position and nothing happens at all. Experience has taught me that the relay panel can be finicky, so the first time it happened I opened it up, massaged a few relays (especially the ignition relay in Position IV), and it started right up. Lately it's been happening so often that I just lean over from the driver's seat and rap on the CE panel cover, and that usually works.

How could I troubleshoot this behavior? I already replaced the relay in position IV, since there was an original one in there, but that didn't help for long. The next day it was not starting again.

I'm thinking about selling this car later this year, and I can only imagine how this type of behavior could be embarrassing when it happens with a prospective buyer.

Barry Chan

I have replaced the electrical switch , relay and fuse, no difference so i just bypass it. It maybe the metal linkage that turns the switch but its not a small job i heard.

safulop

You bypass it.... the ignition switch? You hotwired your own car?

jheis

Could be the the electrical portion of the ignition switch. If yours is original, it's probably due for replacement anyway. Pod has to come off, electrical portion plugs into the back of the ignition switch (engine side). A really short bladed screwdriver is necessary because it's held in by two screws that screw in from the back.

Not my favorite job....

safulop

I'm wondering why I'm talking about relays and everyone else is talking about the ignition switch. There is no indication, so far, that my ignition switch is faulty. When it won't start, no amount of re-trying the key will work. You have to play with the relay panel to get it to start.

FLYVMO

Did you change the starter relay?

Ignition switch is a fairly common failure point if it is original (two of my three 928s failed that way). Especially if the dash warning lights still come one, but of course not the only cause of a non-start.

Cheers!
Carl

Wisconsin Joe

Have you pulled and cleaned the CE panel lately?

Not a hard job. Sharkskin has a good writeup (it's for an early car, but the principles are the same).

From the "wiggling it makes it work" comments, I'd guess there's a bad (dirty) contact or a broken wire.

davek9

If it won't turn over (crank) I'd start with jumping at the 14 pin and see if cranks from there if it does then work inward to the CE, Ignition switch.
If not then go to wiring at 14pin and toward starter.

ltoolio

Maybe the female connectors for the relay(s) are a bit loose, the relay(s) aren't making adequate contact and your hitting the CE cover causes the vibration to go through the mounting frame, to the CE Panel and the relay(s) shift enough to make a good enough connection to start?

safulop

Is the 'Ignition relay' in position IV the one that powers the starter?

**edit
Oops, no, I see it's the one in position XIV, sorry. I maybe have to change that one next.

Jørn

I would not rule out the ignition switch based on re-trying the key having no effect. The kind of fault which typically happens is a lot of corrosion has built up on the electric contacts in the switch causing a to high voltage drop across the switch (to much electrical resistance). This is what happened to me, and this only showed when the engine and thus the starter was warm, reason being that apparently the starter is even more picky when it comes to enough voltage when warm.

But of course if you see effects by wiggling stuff in the CE-panel you're issue might be there or both places. What I did was to start at the battery then follow the starter circuit and measure voltage drop step by step from battery til starter, I stopped at my ignition when it was clear I was losing to much voltage already there

Edit: See now that you have an 88 S4, very different than my 78s starter Circuit, probably S4s do not have same issue as they apparently have a starter relay.

Barry Chan

I bypassed the starter relay with a switch.

Mrmerlin

replace the starter relay

Alan

Starter relay is XIV on an '88.

Only the ignition switch, starter relay, starter solenoid/starter motor and transmission safety switch are involved in cranking the engine over. If it doesn't crank (and the bulb check lamps stay illuminated while trying) - these are where to look. Nothing else.

If the bulb check lamps dim when you try to start - it is something else: battery, ground strap & primary connections are most suspect.

Alan

safulop

Yeah just to confirm with you all, changing the starter relay appears to have resolved this problem. It is interesting how these relays can "fail" in such a way that giving them a little knock will get them working. In my experience this is consistent with the robustness of Porsche parts, they almost fail too gracefully, so you aren't sure if they've actually failed. I've had a long list of experiences with partially or intermittently failed parts on both Porsches I've owned. Other cars, not so much.