Ignition switch and dme relay interaction
 

I too have just gotten the Intermittent no start and it's not much fun . Spare relay does the same thing so I'm ruling that out dme brain master plug is clean and secure .all grounds on the pin map check out.

It will not start Maybe one out of 6 times , today I notice that my ignition switch had a fair amount of play. Tried to start it. No deal Tried again. No deal
Wiggled the heck out of the key the car fired right up.

Every time it does not start I do reach under to feel the relay catch and it does not
But if it does click start up is instant .

Is the circuit for the relay a known problem tied in with the ignition switch ?
88 3.2

I'm not sure how often but I do know the ignition switches get flakey on these cars.
I've heard that using a heavy key chain will make this sort of failure happen sooner.

Isolate the culprit.......
 

AVDCAV,

If you believe that the ignition switch system is causing your intermittent starting problem, I suggest that you try to isolate it. The ignition switch consists of two major sections: mechanical (key and locking device) and electrical (tumbler tumbler with the electrical connectors).

Separate the electrical section and start the engine. An appropriate screw driver could be used to turn the tumbler (start). Repeat test multiple times. If you could replicate the problem with this set-up, you would know the culprit. Keep us posted.

Tony

Not too clear on the no start. Does the engine starter crank when you get the no start, or are you getting nothing at all? If nothing at all, then it may be the tab between the mecahnical and electrical in the ignition switch is shearing off.

It's turns the started just as strong as always
Just the relay will either click or not

If it clicks it starts instantly

Could be a failing reference sensor or DME Relay. The DME needs a signal from the reference (tdc) sensor before it will fire the ignition.

Ed could definitely be on the money....I don't recall reading any post stating that the relay itself has been replaced.

AVDCAV, have you checked the connector that runs from the back of your ignition into the panel towards the "frunk"? I'm having an Alzheimer's moment, and I can't remember the technical name for that damn connection.

I'm thinking it's either that particular connection, one of the connections or grounds relating to the DME (maybe the main cable?), or the mechanical portion of your ignition switch....but only once the DME relay has been ruled out.

EDIT: OK, I cleared out the cobwebs. It's called the bulkhead connector. DERP

Good points heading to garge now

Heres a good thread about the intermittant start issue. Good hints on what to check, and in his case the pins in the connector needed attention.
http://forums.pelicanparts.com/porsche-911-technical-forum/132337-911-mystery.html

Intermittent power from the fuse block was my problem. DME, DME relay and sensors were fine. Nothing works if there is no power to the DME.

Took me a while to realize everything downstream was fine.....learned a lot, pissedmeoff that I didn't start at the beginning.