meek

Oh dear. Yesterday my 964 refused to start. Starter motor churns away , but no attempt at all by the engine to fire up. Was running perfectly the day before.

Before I called my mechanic, I checked all the fuses and swapped over the DME relay for my new spare; nothing. Mechanic popped over with a known working DME relay; nothing. Towed to his workshop and as was now obvious there is no fuel supply or spark.

So, he swapped out the ECU for a known working spare and still nothing and he has just replaced what he assumed would be the logical part to sort the problem, the reference sensor on the flywheel. Still nothing. According to him those are the three obvious bits to check and he will now have to methodically work through it to find the problem. He was clearly surprised that none of the areas checked fixed it, as he says, "964s just don't stop working".

Does anyone have any other suggestions that may speed up the solution? He will find out what is amiss, but anyhing that saves time (££££s) is a plus.

ian89C4

Clogged fuel filter? Bad fuel pump?

Bad dist. rotors? Issues with the coils?

meek

Thanks Ian, but the problem is that there is neither spark nor fuel. Unless two of the above went up the spout simultaneously.

Rocket Rob

Did you check the fuses? It sounds like either a bad DME relay or a blown fuse to me.

meek

Yes Rob, as in my OP, first things I checked. Thought it would be a simple issue at first, but no such luck.

campoj2

Simultaneous dual failure of 2 separate systems is rare, no fuel & no spark, both of those are ignition related. Since you replaced the DME and ECU and it did not fix problem, I would think he problem is downstream of those components, relays/fuses/grounds. Maybe an ignition switch? Maybe an alarm malfunction? Alarms usually cut off those type of things, not sure how 964 alarm works with fuel and spark.

Rocket Rob

Sorry I missed that. I would start pulling out my volt meter to ensure that you have power to the fuel pump and DME. Still seems odd that everything is shutdown.

rarebear

Bad earthing ? try a separate earth line

Makmov

Low batt?

there is a point where the motor will still crank but the DME gets a voltage too low signal and wont fire the engine. Apparently Porsche programmed it so it wont start below a certian voltage.

frankvan

I had a similar problem, turned out to be alarm related after a dead battery.

When i recharged the battery it seemed the alarm reset itself also. So even with the doors unlocked the alarm wasn't allowing the car to start. A turn of the key in the door to properly turn off the alarm and she fired right up. Of course that was after a week (seven full days!) of hair pulling and cursing. At least that's what i think happened (car started so i was happy anyways).

Kuchar

Aftermarket alarm?

meek

Thanks for all the input guys; RL really is great. The alarm may very well be the issue, but it is the original Alarm System 1. The immobilser key is working fine; if it wasn't, I wouldn't even be able to crank the engine. The battery is new and very strong, so I don't think that is the issue. I am now thinking dud earth or power to DME as suggested above. Ollie the mechanic is hopefully attacking it now, so I will call him and see what gives. Will post up the solution when it is reached.

Am now at my girlfrind's house having endured public transport to get here. Now I know why I drive! 2 1/2 hours and £40 for what is normally a 1/2 hour £6 car journey.

CBR786

Sometimes the ECU has two sets of wires coming off and they be bridged looped depending on car model & country it is going to. I know this bridging is a 12 volt live & the other is possibly a earth so if your loom by the ECU has these two wires ending open & not bridged maybe come loose that could be the problem. Also if you manipulate a live to the DME relay from the car battery I am sure the fuelpump will start running and car should start. I understand you gave no spark but if no live present at the dme relay then fuel&spark will go. Please research my advice as I am not a Porsche mechanic lol and maybe talkin rubbish

frankvan

And now just a day after posting in this thread myself my car won't start!

It's been sitting dormant for about a month (replacing PDAS interlock seals on tranny) and it's been cold. Kept battery on charger for last two weeks as it was cold out (-20 daytime highs) and knew i wouldn't be driving it. Like others, it started and ran perfectly prior to it's short sleep.

SO now i've tried all the things in this thread and others i've searched. Different battery, jump starting from another car, switching coil wires, switching igniter module connectors, reseting alarm, removing air filter, checking connections to MAF, idle switch, etc... I've also tried jumping the DME (pins 7,5,3) and can hear the fuel pump running (7 to 3) and something goes click (DME?) with 7 to 5. Still won't start.
Now it is still cold so maybe i just need to wait for it to get above the freezing mark and try again.

Only thing i haven't done is check the scantool codes - might be something there maybe?

Richard Curtis

frankvan: does the engine turn over, or is it dead as a doornail? Car needs four things to start: fuel, spark, timing, compression. Most non-start problems are either fuel or spark, especially given your symptoms of suddenly not starting. Check that you're getting fuel to the spark plug (spark plug should be wet with gasoline). Check for spark by grounding a plug and observing the color of the spark... if any color other than blue, you've got a bad coil(s). Of course, your non-start might be due to other factors, too, but these are a start (no pun intended).