frankvan

it turns over like a champ. It even coughs and sputters once or twice every couple of seconds while cranking - it wants to come to life but just can't manage.

I'm thinking with the cold weather i may have a gas line vapour lock or just an unhappy car. It's supposed to warm up this weekend so i'm just holding out for then.

Rocket Rob

If you get a can of starting fluid, will the engine run for a short period? Do you have the ability to check the fuel pressure? I'm wondering if you have a faulty fuel pump that's getting power but is not providing sufficient fuel pressure/volume.

frankvan

with the fuel lines running along the bottom of the car would it be possible for water in the fuel to freeze and block the fuel flow? The pump is definitely running when i bypass the dme relay (pins 7 and 3) and i can hear what sounds like fuel running through the lines when i poke my head in the engine bay.

meek

Looked like mine was sorted out this morning. Bad dry solder on the immobilser under the passenger seat. However, having picked the car up, it now cuts out intermittently Hopefully just something loose after the repair.

CBR786

maybe your workshop removed battery and the DME needs to be reset? Adaptive settings out can cause stalling when you clutch in.

6. If the relay doesn't fix it, it could be the DME computer itself, faulty sensors
(flysheel speed and position), or faulty grounds. Try disconnecting the DME
computer and cleaning the contacts.
7. Check all ground connections (brown wires) for corrosion. Disconnect them,
clean them, and replace. Check especially the ground points in the engine tin.
There's on on the manifold pipes, and another on the left side of the engine tin
behind the fuel filter. There is apparently another one on the bottom of the car
coming from the flywheel area.
8. Check all fuses for corrosion. Remove each fuse and replace. All DME-related
fuses are up front, but there are three fuses under the plastic cover at the left rear
side of the engine compartment.

boxsey911

Sounds like you might need a DME reset (especially if they disconnected the battery while fixing your alarm). A C4 usually needs a Hammer to do it (A C2 can be done without). The other trick is to disconnect the earth lead from the battery for a minute, put it back, fire up the car and put lots of electrical load on it (lights, heated screen, fans) while it idles up to temperature. Once up to operating temperature take it for a good blast.

Unkle

Glad you got it all sorted

meek

Unfortunately, a DME re-set is what I thought it might need, but it is down at the workshop again and it won't start, again. Bugger!

boxsey911

Bugger! +1

meek

UPDATE: Finally solved and typically annoying. The 12v feed to the ECU from the front fuse board is faulty. Seems to be supplying power intermittently, so probably damaged, but how is a mystery. Waiting to see what the cable looks like when it comes out of the loom. Simple to fix yet expensive to find Thanks for all the great help, as always.

dhc905

Question: mine won't start now. I haven't started it in a two weeks, but unplugged the positive terminal to make sure it doesn't run down the battery.

Anyway, when I replugged the battery the interior light didn't come on, which would suggest a dead battery. I tried jump starting with my other car, which hasnt been started in a week or so, and all the lights come on, the engine turns about 1/2 a turn then stops.

Took my other car out for a ride to charge the battery, cam back and tried again. No dice.

I have been trying to get my passenger door unstuck by futzing around with the interior mechanism, which is protected by an anti-theft thing. I've tried moving it around, but it's not removed.

So question: would driving a couple miles charge my other car enough to start the Porsche or does it need to be totally charged?

Is there any chance that futzing around with the door interior has immobilized the car via the alarm or something?

newsboy

A bad flywheel speed sensor would explain no spark and fuel. You can test for this. To test this, I opened the DME relay(under drivers seat) and used a multimeter set to AC voltage, across pins 47 & 48 of the large plug. iT's supposed to read 3 volts.

dhc905

I'll try that if I can't get it to start by letting the jump connection stand for longer.

I did notice that after unsuccessfully trying to jump it, the interior light came on and stayed on, albeit quite weakly. So clearly there was some charging going on in the short period of time I had the two cars connected. I read up and it said to let them be connected together for 5 minutes before trying to turn the motor. I didn't do this, potentially my problem?