ehall

If you are sure about that, then do one simple thing. While someone cranks the car, wiggle the speed and ref sensor wires. They tend to erode at the ends and the internal wiring makes intermittant contact. It can cause all sorts of issues. The tach will often still bounce but not fire. I've been through this. If you do this and nothing, continue, but start moving wires around. BTW, how many volts are you getting from your battery? It should be more than 13. It may still work with less, but not well.

After that, you need to consider compression.


I got fitty bucks that it's something simple, like the battery or a cable or wire.

zerMATT951

The 2 square connectors go to the speed & ref sensors, the round connector is the O2 sensor.

Be careful if you disconnect the S&R sensors at that point... these cars are so old that just touching them can cause the connector plastic to crumble in your hands. Try to wiggle the wires without disturbing the connectors first, then if you want to dig deeper, you can unplug them and inspect the blade connections for corrosion... very carefully.

audisport

Yup, mine are completely destroyed from moving them while doing my HG. I have them pushed together and wrapped in electrical tape to stay together right now. I'm about to order male/female of these plugs so I can rebuild the connections.

http://www.efiexpress.com/catalog/pr...products_id=21

http://www.efiexpress.com/catalog/pr...products_id=62

ehall

If you do a search here, there is a thread where we found the proper connectors. The parts and components exist to rebuild the whole thing. Also look up "TexasBlake" on RL.

jason952

timing belt is OK based on this info, but could still be old!

spanky

I have had this happen to me a few times with both my NA and the 951. I changed the 2 fly wheel sensors then disconnected the DME harness connection plug cleaned it with contact cleaner , checked for loose wiring leading into it then reconnected it. As said above the coil can go bad with out warning If the rotor screw becomes loose the rotor will come off of the shaft and ruin ihe inside of the cap, you will know it with out question when you look inside. Good luck

David.N

Update : Still wont start

So far I have replaced the Rotor, plugs, wires, cap, coil, reference sensor, and DME relay.

I found some frayed eroded wiring on a wire going to the reference sensor. So next im gonna try fixing that. Then I guess clean DME computer 24pin connections?

Im gonna go talk to a real porsche mechanic and ask for his opinion too, cause that always helps.

ehall

How much voltage are you getting at the battery? Don't say, "It's a new battery." How much actual voltage are you READING at the battery?

ehall

ps usually when the car just dies while running down the road, it's an alternator failure, which means the car had been running on pure battery power before it died. Therefore the battery will be drained to the extent that it will show voltage, but won't have enough to crank the car. That would give you what you are seeing.

spanky

Is it possible that a 2nd problem has piggybacked upon the 1st. you have gone through the engine control / battery/ DME and found nothing amiss. What if now the fuel rail in empty of fuel due to bad fuel punp chk vlv, leaking injector or fuel regulator??.

ehall

^^ not an invalid thought, but I stand by the easiest first. That has still not been conclusively ruled out.

Campbelljj

Just to be sure disconnect the AFM harness clean both male and female ends and reinstall. I had the connector pull away enough to leave me stranded once.

David.N

Thanks for all the input, I cleaned the maf sensor connectors. Definitely getting fuel I can smell it.

So i am getting a current to the ignition coil so the wires are fine, turns out it might not be sensors/dme etc. I got 5volts out of the coil, but my 944S got 110ish volts so it might not be getting enough power. So ehall you might be right! Do the wires that supply power to the ignition coil come from the alternator? anyway to test my alternator? doesn't sound too hard to replace are there any complications in the process?

onspeed

I'm pretty sure the coil wires do not originate from the alternator.

Check relays and fuses?

I had a issue a while back where the car just died at a stop light and I couldn't get it running again. Turns out my 15 year old MAF sensor broke. Physically. But you're saying no spark so that's probably not it.

Oh, does your car have a factory alarm?

Bri Bro

The ignition coil hot side comes directly from the ignition switch. No fuse inline.
Just follow the line from the coil to the ignition switch. https://rennlist.com/forums/7559251-post25.html