911 Not Starting !!!

[scarceller]

This may be a bit late for some but the BMW Ref/Speed sensor is identical to the porsche one at 1/2 the cost. Our host sells them search for:
12-14-1-708-619-M14 (this is the BMW)
911-606-215-01-M14 (OEM Porsche one)

I've used the BMW sensors just fine in the 84-89 Carrera.

[JG911]

Any ideas with my coil not switch over

[rick-l]

Originally Posted by JG911

Any ideas with my coil not switch over

We need that translated into english

[JG911]

The auto sparky has a tester which went onto my coil and it had a 5 LED lights and when he put the tester on the Volts/AMPs On light came on And when we turned it over the/Volts AMP's Off light came on and he said it should be the other way round.

[scarceller]

Originally Posted by JG911

The auto sparky has a tester which went onto my coil and it had a 5 LED lights and when he put the tester on the Volts/AMPs On light came on And when we turned it over the/Volts AMP's Off light came on and he said it should be the other way round.

I'm not sure what you mean but keep in mind that the 84-89 cars always have 12vdc on the '+' terminal. The DME grounds the '-' terminal to charge the coil.

So if you measure voltage at the '-' terminal with key in 'RUN' engine not running you will actually measure +12vdc on the '-' post because the coil has very low resistance. Then when you crank/start the car the '-' post gets grounded and you will see 0vdc. I think this is what you may be seeing.

[JG911]

Hello the coil is sending a signal when it should not and when it should not send a signal it does ...

Th icv is working iv just checked it.

[JG911]

Hello Everyone.

Just like to thank everyone for there suggestions been a big help.

This evening i had a friend round auto sparky and he checked all the wire's and the crank and ref sensors and there all fine and so are the earths.

The problem is the ECU and he think's its a yellow box type think in the ECU.

[scarceller]

That is resistor R503 (150ohms) and is part of the ignition coil drive circuit. If that resistor is bad I don't think you will have spark. You sure it's bad? test it with an ohm meter to see that it measures 150ohms.

More important do you have spark while cranking? Disconnect the coil wire from the distributor center post and see if you have spark while cranking.

[JG911]

Hello scarceller

Derrick did test that resister and i think it was only 5volts im sure he will pop on later and tell you more technical side of it.

[JG911]

The ECU Doctor has found the fault with the ECU.

[dk's77911]

no spark should be corrected 1st... likely coil or ground problems, check a different plug wire with a new plug, replace easiest less expensive parts 1st, I am thinking coil problem, good luck

[JG911]

Hello everyone i got my ECU back this morning and iv connected all up and still no joy of starting,what its doing now is turning over then a pause then turns over again then pause and so on ......

Any ideas ???

[JJ 911SC]

Originally Posted by JG911

Hello everyone i got my ECU back this morning and iv connected all up and still no joy of starting,what its doing now is turning over then a pause then turns over again then pause and so on ......

Any ideas ???

JG911

The thread is getting long, actually I thought it would have been solved by now so I just check to see if it had went on a interesting tangent...

A lot of people (me too) got their set up in reverse so we see the last posting and might not be going back far enough...

Keep this thread going but I suggest to you a reply with every things you did so far along with any change in the symptoms at any given step.

Good luck

J.J.

[JG911]

So far we have done.

New Car Battery.
Both Fly Wheel Sensors.
Rotor Arm.
DME Relay.
Ecu Repaired.

Checked fuses and checked ohms to the fly wheel sensors all ok.

And now it's turning over then a pause then turning over then a pause and so on.

If we got the flywheel sensor's connectors the wrong way round what would that course ??

[ischmitz]

The ECU and its sensors have nothing to do with cranking. Either your battery is dead, the ground strap is marginal or the connections to the starter are loose.

Ingo

[JJ 911SC]

Originally Posted by JG911

So far we have done...

And now it's turning over then a pause then turning over then a pause and so on...

How long does it turn over before the pause?

Is it long enough that it would have start prior to having this problem?

[JG911]

If the battery was dead i would have thought the battery would not keep turning the engine over is would just slow down and stop !!!

[JG911]

Originally Posted by JJ 911SC

How long does it turn over before the pause?

Is it long enough that it would have start prior to having this problem?

I think it stops at the point were it would have started if all was ok.

[JJ 911SC]

... easy to say when you are thousand of mile away.

With all that cranking, if you can (not sure if you have taken a spark plug yet and don't feel bad because I'm not sure if I would do it myself...), take a look a one of the plug to see if its wet?

I went back to you first posting... do you now have 12 Volts on the coil input and do you know if putting out correctly?

[JG911]

Originally Posted by JJ 911SC

... easy to say when you are thousand of mile away.

With all that cranking, if you can (not sure if you have taken a spark plug yet and don't feel bad because I'm not sure if I would do it myself...), take a look a one of the plug to see if its wet?
No iv not taken any plugs out to be honest,that looks like a job on it's own

I went back to you first posting... do you now have 12 Volts on the coil input and do you know if putting out correctly?

The coil had power going to it and we tryed to turn the engine over it ground out,the ecu fault coursed this we think so sent if off to be fixed