samimi

On a warm day last week, my '88 911 engine died while idling and wouldn't start up again. I let the car cool down for a day but even then is still wouldn't start.

I had it towed to my non-Porsche mechanic ( mistake, but oh well...) but he can't figure out the problem so far. He says the ignition coil is getting electricity but doesn't seem to get it to the spark plugs. He changed the coil twice with a new one but still not starting. He says there may be a grounding issue. (???)

I've had this problem before and it was a 'head sensor' according to my old repair receipt.

Furthermore, researching the old posts, the DME relay seems to come up quite often as a possiblity.

Could any of these be the problem? Any thougths would be appreciated.
Thank you,

cal44

Do you have an old alram on the car? That was my problem. There are so many great Porsche indys in San Diego.............why would you.......never mind

931GT

I have the same issue with my 85', I replaced the coil but still no change. I'm getting my new DME relay in an hour or two... I'll let you know how it goes.

931GT

Nope just replaced the DME relay... still no start.

931GT

Did some testing with my Multimeter and looks like its a bad reference sensor. I'll be replacing it in a few days.

rusnak

Use a dental pick or a very small screwdriver to remove the spring steel retaining clip from one of the injector connections. You need to get more than 12.v You can also turn the key to "run" and see if the ICV is humming. If there is no voltage, then it could be the DME relay or a problem with the DME brain. If the voltage is low, then clean your battery connections, check tightness of grounds and the power supply. The coil gets power directly from the switch. At some point about I dunno, 6 months ago we put together a Rennlist "no start" checklist for the 3.2 911.

931GT

Turned out to be the reference sensor on my car. Replaced it, which BTW is a major PITA, and it starts and runs just fine again.

There is a simple test with a multimeter to check your speed and reference sensors.

theiceman

you guys and these cars with these sensors everywhere ... get something solid next time .

So just for reference ( excuse the pun ) is it measuring crank pulses ? or cam pulses ?
ie where is it located ?

931GT

Crank pulses. On the 3.2 there are 2 sensors, one for starting (reference sensor) and one for running (speed sensor). All motronic managed engines have these.

88CarreraTarga

Just wanted to add that performing a spark check at the end of one of the spark plug wires using a spare spark plug will also validate that the sensors are working OK, as they are a key input to the DME to trigger the coil to fire. So if you aren't seeing a spark there, start checking back up the line and check that there is 12v (or so) at the coil. If present, then the problem is possibly the sensors, etc.

If spark looks good at the spare test plug, then the problem is likely something in the fuel delivery system.

BTW, I searched for the referenced "no start" checklist for 911 3.2 but no joy. Is it still available?

theiceman

Not sure what the op found but I hope tried a dme relay. Never hurts to have a spare

jakeflyer

---iceman--- maybe there is a mod kit we can make to put sensors into the SC so that we can understand these discussions?? At least we could join in. just sayin

88CarreraTarga

@ iceman, speaking of fuel/dme relay, what do you guys think about the non-porsche OEM relays? Ever see any issues with using those rather than the $120 Porsche versions?

ricster

Had this issue a few years ago myself, seems these sensors go after 20 plus years

vracer

I burned up a very expensive 'black box' on a (non-Porsche) race car one time by pulling the plug wire and checking for a 'wire to ground' spark. Do you ground this spare plug? May I assume the Porsche boxes are not subject to this sort of failure. Thanx.