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Engine cut out abruptly - '87 944 turbo

D

dunc

New member
Pulled out of my parking space at work today and got about 10 metres and the car abruptly cut out, dead as a stone. Won't start now.

Jumped the DME relay in case it was that, then put more fuel in. Finally checked the ignition and there was no spark, tow truck home.

Investigating more this weekend but if anyone can provide good suggestions I'd appreciate it. About to have a look through clark's website.

Thanks,

Dunc.

Edit: Sorry missed some important information. It's turning over fine but just not starting so not battery or starter related, also could clearly hear the fuel pump working with the DME by-pass jumper connected.
 
When you crank it, do you get any rev counter "bounce"? If the rev counter is not moving then suspect the speed/reference sensor(s).
 
GlennS said:
When you crank it, do you get any rev counter "bounce"? If the rev counter is not moving then suspect the speed/reference sensor(s).
Click to expand...
The rev counter was a bit irratic, sometimes bounced sometimes just wobbling near the bottom. I've never paid much attention to it during starting before so wasn't sure what to expect.

Thanks,

Dunc.
 
check the multiplug's for the two sensors, plugs are mounted at the rear of the inlet manifold

Pete
 

Check the distributor cap or even try another one.
Regards.
Zeusy.

[/quote]
....and of course the cam belt.
 
My car just stopped on the A1, I took the dizzy cap off and the rotor arm was burnt to a crisp. New rotor arm and all going nicely again. My point is look for the simple things 1st.
 
Remember to check the rotor arm screw too, Edh witnessed my complete fail at not diagnosing that the only time my Turbo has let me down. Completely my fault too as I forgot to loctite the screw after renewing the HG. Duh... That was an embarrassing one.

the irratic tach bounce does point towards the reference sensors or the wiring. A guy in the US on one of the facebook groups recently spent weeks chasing down a similar issue to finally discover the loom was split internally at the plugs at the inlet... It's normally something very simple, after all they're pretty simple beasts!
 
Thanks for all the responses, great stuff :)

Today I put the recharged battery in and it started then cut out after 5 to 10 secs again then wouldn't start. Annoying but rules out cam belt or large mechanical failure.

So working through the suggestions above.

1) Distributor cap all OK
2) Speed and reference sensors, plugs look OK and resistance through the sensors seems good.
3) Had a general look around the wiring but nothing is jumping out.
4) The tach bounces up once towards the 1k rpm then just modulates slightly lower down as you continue to crank, sound reasonable?

Is it worth trying another ECU to rule that out? There's another one regularly in my car park at work so I could maybe find the guy ask to swap them over for a try, it's a turbo but not sure what age.

Does DME computer = ECU?

Cheers,

Dunc.
 
DME is a relay that "switches on" fuel and igntiion when cranking, stick a spare spark plug in the end of one of the leads and earth it you should get a good strong white / blue spark if not ignition fault.
Crack the 19mm plug off the end of the fuel rail and crank again, it should spit fuel out so no heat sources and have some rags available to catch the fuel, no fuel then a fuelling problem, don't get too involved double check the basics, check the distributor cap where the leads go not just the internal as a small amount of corrosion wil cause problems.
 
DME is the ECU yes. The DME relay powers up the DME and the fuel pump when the engine is turning; maybe someone could clarify where the DME relay takes its trigger signal from?..

ETA: it's a common misconception that the DME is the 'DME relay', but it's not. DME is what Bosch named their motronic ECUs. Probably a German language thing?..
 
Richair said:
Remember to check the rotor arm screw too, Edh witnessed my complete fail at not diagnosing that the only time my Turbo has let me down. Completely my fault too as I forgot to loctite the screw after renewing the HG. Duh... That was an embarrassing one.
Click to expand...


:ROFLMAO: We were ready with all sorts of complicated theories weren't we?...and it's usually simple. Interesting that it started but then cut out. Clarkes garage has good troubleshooting guides.

 
The DME relay takes it's signal from a crank sensor, as said don't get too deep and double check the basics.
 
It started again and ran sweet as a nut for 3-4mins there, then cut out once it had moved a few metres (it decided to stop at an inconvenient spot in the drive, thanks)

Think I've ruled out the distributor and leads, getting a solid 12v reading at the distributor and all connections look good. I don't think it's anything too nasty since it runs so well sometimes, dodgey wire I reckon.

I'll get back to the investigations soon!

Oh and does anyone know what this is (attached)? Sitting just above the ecu, tricky to get at.

Thanks,

Duncan.


 
Looks like an alarm or immobiliser, not factory by the look of it, pull the plug leads out of the distributor cap and check the lead connectors and the cap connectors especially the king lead.
sounds exactly like my symptoms and it was the connection on the distributor cap King lead with some very slight corrosion.
 
As said could be an immobiliser but from the look of the cable coming out of the 2 o'clock position may be a aerial amplifier. this is normally fitted under the drivers side under the windscreen.
 
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