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Sparkless?

Hairyarse

Hairyarse

New member
Thought I'd go for a drive today, for no reason other than I haven't taken the Porker out for 2 weeks. She started on the button as normal, ran as sweet as normal and after about 10 minutes just died and wouldn't restart.

There was no warning at all, just stopped at a junction and wouldn't restart. Fortunately I was just down the road from Rob's (cheers for the help mate and thank the missile for the coffee[;)]) the engine turns over fine but won't start. Tried with Robs DME relay but no difference. We check roadside for a spark and nothing at plugs or at the coil.

We towed her home ok (thanks again Rob!) so, any thoughts? Could it be the coil, would it just go without warning? I haven't checked my history file yet but have a feeling that the coil was replaced not so long ago.

Answers on a postcard.....

Cheers
Andy
 
First thing to look at (because it is so easy) is whether the tacho needle "bounces" whilst it is being cranked. It is a slight, but definite bounce. If it doesn't bounce, there is no signal from the crankshaft sensors.
 
just some random thoughts:

Have you tried cleaning the plugs for the crank/cam sensors?

Is the wiring for the crank/cam sesnors damaged in any way?

The DME hasn't got wet has it?

 
Along the lines of the crank and cam sensors - I see a repair harness being advertised for these connectors as apparently the wiring can fail with age (heat, moisture, oil, etc). Details here: http://www.autobahnextremist.com
 
Thanks for all the tips and helps guys, I've got no time to look at her this weekend so will report back when I can!

If the sensor is the issue, will that stop a spark being generated?

DME can't be wet, car's been under cover since I last drove her

Many thanks
Andy
 
Is this like some weird 944 synchronicity?

My race car has this problem, drove all the way to Silverstone and back no problem also drove up to Brum yesterday all without missing a beat. Put the car on a race track however and it cuts out after about 15 to 20 minutes or so, then can be restarted and shows a dead rev counter. What is worse is that she was run on the chassis dyno only about a fortnight ago and again didn't miss a beat.

This and the other thread about steering wheel shimmy, amazing coincidence.
 
Ok, so had time to get the cover of my baby for the first time since she stopped working!

The rev counter is not bouncing when I turn her over, so guess that means the sensor? However, I am a little confused about one thing. OPC Leicester came back on the sensors when I asked for a price to confirm that there's only one sensor for pre-84 cars like mine (Timing mark sender) which is highlighted in the pic below they sent me
image001.jpg


However, what I thought were there sensors are numbered 10 in the diagram.I've emailed them back to confirm but any tips would be appreciated.

I also noticed the connectors for plugs numbered 10 were flopping around in the engine bay. I saw there's a small post with a bolt in it at the back of the inlet manifold, it seemed logical that this is where the connector bracket should be mounted. I've attached before and after pics below, would be grateful if someone can confirm I've bolted the bracket to the right place [;)]

Before
IMAG0134.jpg

After
IMAG0135.jpg


Cheers guys
Andy
 
The two sensor numbered 10 are the speed and reference sensors and both are identical parts. The symptom of a failing reference sensor is that the car won't start at all - no spark. But my understanding from the RAC man who diagnosed mine, was that once the car had started it would run and not cut out. This ties up with the issues I was suffering which was intermittent starting but once running it ran fine and didn't cut out. I've had a speed sensor go on the focus and the symptoms there were that the car ran fine but whenever I depressed the clutch, say when approaching a junction, the revs would drop and not settle at idle revs and just stall. Not sure if this would be the same symptom of the 944 system. So on the basis your car cut out then it might not be the reference sensor, though could be the speed sensor if it cut out when you disengaged the clutch at a junction for example.
 
You have fitted the bracket correctly. The OPC have highlighted a diagnostic sensor - this isn't connected to anything! The 2 sensors numbered 10 are the correct ones. Before replacing them you need to check you have a 12v supply to the dme relay. The sensors can be tested, check for an ac volt output across the 2 outer pins whilst cranking. The car will not run if either of these sensors is faulty, one is used to supply the ecu with a speed signal, the other for a tdc signal.
 
Thanks for the help guys, I'll have to try that.

...and yes, the car died at a junction when I depressed the clutch

Thanks
Andy
 
Andy

This sounds to me exactly like the problem I had with my turbo a few years ago - one of the sensors had gone down and even the RAC man couldn't figure it out !

I would try borrowing one of the working ones from the chap in Leicester and see what effect this has,

Chris
 
ORIGINAL: A9XXC

Andy - I have them sitting in the garage if you want - or maybe Elliott is easier to get to?
Click to expand...

Cheers for the offer Mike, will let you know - Elliot is just up the road though - Still, I need some time to look at it first - off overseas early hours again :(
 
Can't believe it's taken me 6 weeks (work 'n' all) but new sensors (cheers Elliot!) fitted and she works [:D]

Battery was dead but a jump start sorted that, was great to be driving her again [8D]
 
That's fantastic news mate! Maybe it's a good idea to have a little cambridgeshire/leicestershire meet'n'drive before mine breaks[:D]
 
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