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No start mystery. 3ltr S2. Ignition experts

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Old 01-03-2018, 02:11 PM
  #1
944volks
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Default No start mystery. 3ltr S2. Ignition experts

My 1990 3ltr engine has been running fine.
sometimes a little temperamental on hot restarts but been running nice.
last week I pulled in a petrol/gas station.
restarted.
drove 1/2 mile engine died at lights.
couldn't restart.
one or two flutters but no good.
get towed home.

​​​​​​Turning over but no start and no rev-counter bounce.
change reference sensor.
starts. Turn off. Restarts..... revs lovely.
leave on tickover.
After 10mins engine just cuts out again. (Like reference sensor has been disconnected )
will not restart. No rev-counter bounce.

Think it must be a dodgy connection on the reference sensor circuit. (Right? Anything else?) But I can't find it.
where should I look.
Thanks guys.
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Old 01-04-2018, 02:44 PM
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Start here:

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Old 01-05-2018, 11:10 AM
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Hi Paul
Yeah found that but my ecu has a 3 row connection.
using Google my pins for speed/reference sensor are 47 and 48.
I did omh test on 2000 it read 845.
Then switched to AC voltage and turned it over.
I got reading of 3 to 4 volts.
Any thoughts?
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Old 01-05-2018, 11:15 AM
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Tried starting. Nothing. No tacho bounce.
��
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Old 01-05-2018, 12:45 PM
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taking a stab, but have you tried a new dme relay?
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Old 01-05-2018, 07:57 PM
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I then took a omh reading direct from Reference sensor and it gave the same 845 figure.

I have 3 DME relays with car, so thought yeah what the hell, and started swapping them in.
On 2nd relay, car started, reved (alittle stuttering), turned off, restarted, turned off, restarted, turned off........ No Start!

Loose connections under fuse box???
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Old 01-06-2018, 03:55 AM
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Yeah, or a bad socket. Look for corrosion or bent contacts in the socket.
Or better yet, try jumpering the DME relay, check Clark's Garage for details.
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Old 01-06-2018, 11:14 AM
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Good points.
I've tried jumping earlier I can hear pump but don't know if its just intermittently working .
lve lifted out fuse box...... jeeeez its scary.
removed a couple of wiring sockets near DME relay.
but how the hell do you get to relay socket?
scared! Lol
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Old 01-11-2018, 07:09 PM
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You might try resoldering the contacts inside the DME relay. If they are as old as your car, the solder points can develop hairline cracks that prevent current from passing. Heat can effect this, so that's why your car can start and run only to cut out mysteriously.

Remove the cover from the relay and touch each contact with a hot iron, re-flowing the solder. See if this helps.

Another place you might look is under the boots for the wires running to your reference sensors. They can be a place where intermittent electrical gremlins lurk.
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Old 01-12-2018, 09:01 PM
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Alarm unit.
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