at wits end...

[exitwound]

What happens when you attempt to start it and it doesn't start? Does it crank normally or do you get nothing?

[Skytrooper]

It cranks normally, just won't fire.

[mattdavis11]

the tach doesn't move while cranking either.

[carlege]

Originally Posted by mattdavis11

the tach doesn't move while cranking either.

So it dosent move?

[exitwound]

Originally Posted by MattDavis11

It's the power lead (DME, red) from the positive terminal on the battery. Cut the sheath back to see how much needs to be mended.

But if it's cranking normally, why would it be the positive cable from the battery? A drop in voltage across the circuit would create a sluggish starter, or no starter activity at all, would it not?

[Grandad#3]

The next time the car starts take it to Auto Zone and they will check the alternator and battery for free. I went through three new batteries in a 6 month period one year. Just because the battery is fairly new doesn't mean it can't short out inside and your recharging it all the time.

Cheers,
Larry

[Outback Porsche]

Originally Posted by Skytrooper

No alarm on this one.

Nope, diconnecting and reconnecting speed sensor didn't do it.

Disconnected and reconnected all sensors...no dice

Put battery charger on and turned key...vrooom...it starts

Gol dang car !

Bugger! I though I had the answer for you.

What I think is happening is you have a voltage drop problem. A wire somewhere (maybe more than one wire) has a resistive connection and the DME is not getting enough volts to run correctly or it's not sending correct signals out.

This maybe on your supply rail to the DME, or it could be a sensor, or it could be the wire to the coil, or it could be a ground connection. Sorry, being intermittent, it'll take some time to find it. Get a schematic and a meter and check off each electrical connection methodically. In some cases (depends upon the signal involved) a few ohms resistance may be all that the problem is.

Cheers

[ballysdad]

Had the same problem I could start car if I hooked up a battery charger had exact same symptoms. It turned out to be an open in the harness that goes to the starter. A high open can be jumped with more juice ie: the battery charger. I hooked up a voltmeter to my starter and waited for a no start again when I did I was only getting 7v to the solenoid. To save time fixing it right at first I just installed a start switch in the car to supply 12v to solenoid when I needed it worked like a charm..

[Skytrooper]

It is fixed and reliable again ! I gave it a couple days just to be sure. Replacing speed and reference sensors did the trick. She fires up immediately and runs strong. I did break the sensor bracket to get the speed sensor out, but I am sure it was a good thing as it allowed me to reset the sensor gap. I took the advice and used a bad sensor and glued a washer (of appropriate thickness) to it as a tool for future use. I bought the BMW sensor (sorry, but with 3 porsche mouths to feed...all demanding my paycheck...I had to cut costs somewhere).

Many thanks to all who helped point me in the right direction !!

[TSNAPCRACKLEPOP]

so once agAIN, you find yourself at "wits beginning" instead of wits end"!

[Skytrooper]

I would agree with the "at wits beginning" , but it is a 944...so in actuality, I'm just waiting for the next issue to arise.