87 Carrera won't start - Probably not the DME relay!
 

This spring the battery died so I got a new one.   Shortly thereafter the car died in the parking lot.   It would start and run well for roughly 10 seconds but then it would die like it was starved for fuel.   Had it towed to the shop.   They put a new DME relay in the car which seemed to work.

I drove it to work, it died there.   Rapped on the relay, it started.   Drove it for about 10 miles, no issues, no loss of power at highway speed.   Then I got it home parked it on the street to move my wife's car out of the driveway.   Again it wouldn't start. Rapped on the relay again, it started got it in the driveway and then it stalled again.

OK, now there my 911 sat for about 3 months.   I have a good excuse, I had major surgery.

Now I am trying to get it running again.   First thing I did was go get a another new DME relay.   That didn't work   Engine rotates, but no hint of it starting.

I have the seat out of the car now.   If I jump the two sockets in the plug for DME relay and you can hear the fuel pump hum.   However, with the DME relay in place turning the key to the ignition produces no hum from the pump.

What are your thoughts?   Bad DME or something else? :(

I had the same problem and it turned out to be the flywheel sensors, two of them (speed and reference). Had them replaced and all is ok. I had done all the obvious stuff, rotor, cap, coil, DME relay, fuel filter. I actually used the BMW sensors which are direct replacement for Porsche but much less expensive. There are a couple of threads on it.

Sorry i didn't mention but hope the surgery went well.

Me too!

+2 on the speed and reference sensors...but there are lotsa things that can contribute to a non-start issue. As with any vehicle, you're gonna need to check out the 3 things that make an internal combustion engine operate...air, spark and fuel. The fuel pump may whirr, but that isn't a guarantee that your motor is getting fuel. That's the first thing I'd check. :cool:

Thank you gentlemen. I will try a search on those sensors.

The surgery was a removal of the gallbladder with minor complications. All is well now though. Thanks for asking.

x3 on the sensors. I just put the bmw ones in and it solved it.

I had mine done by a shop in CT. I saw where they were located and wasn't really comfortable getting to them. How high do you need to get the car and how difficult are they to reach? I'm just counting on these lasting another 120K miles as the originals did.

Glad all went well on the gall bladder. I had a very good friend that went in for the laparoscopic procedure on a Wednesday and was dead by Sunday. Not a good story.

They can be replaced fairly easily, but it can be a PITA. They are kind of difficult to pull and re-install because the area is pretty confining. The rear driver's side needs to be jacked up, and the rear wheel needs to be removed. This will be the easiest part to do, obviously.

You also need to make sure that both sensors are within specs regarding their distance from the flywheel. If not within specs, your motor will not run. :(

Well the job has been done and car running smoothly so I'm a happy camper.

changed the sensors myself, and it is a pain in the ass for sure. but search on it here. it is possible and straight forward to do. just be careful with the mounting bolts.

I also did the flywheel sensors myself using the bmw parts myself - with zero porsche experience. Bmw (bosch) parts were the same and cheaper!
However, I had combined it with the primary winter tasks of doing other work, so my entire intake manifold etc was out of the way. I imagine you may be able to fish them thru the firewall grommet w/o removing the stuff I already had out.

To get to the sensors and the grommet, with the rear up and on my trusty pep boys jack stands (which weren't too high), and the left rear wheel pulled, I was able to get to the sensor mounting points and grommet.

If the sensor wire insulation is cracked and falls off by touching they're probably due.
Make sure it wasn't anything else tho'.
I don't recall which end of the sensor I pushed / pulled thru the grommet.
Verify spacing during install (sensory head to flywheel) - I think a coin worked, don't recall exact distance.

Hope this pic helps = am looking over top of brake/disk.
Two sensors evident with white wires (black insulation crumbling off)
http://forums.pelicanparts.com/uploa...1255904534.jpg

Excellent photo Steely!

Thanks very much, for your help. :D

You can save yourself a few dollars by reading this....

http://forums.pelicanparts.com/porsche-911-technical-forum/332727-inexpensive-carrera-speed-reference-sensor-alternative.html

Did you read any of the previous posts?

Just for clarification, I think I now recall having the ability (due to the space I had) to pop the entire grommet (oval), inserting the wires and re-inserting the grommet. I don't wanna mis-lead. And I never had to use a coin (don't do it near the flywheel in case it gets dropped). I think I went for it/lucked out with the sensors being the proper size and me just tightening down on them.
If you pop a plug and get no spark, that's another clue.
And by all means, chk your fuel situation as mentioned above first.

Best of luck!