My 16v is not sparking after having the gearbox reconditioned.


I have narrowed it down to the ignition computer - you know the one mounted on top of the wheel well, or the crank position sensor. I suspect it's the position sensor since that is very near the gearbox and causes the spark, but want to test it before going through the cost and effort of replacement.

A resistance test confirmed it has correct resistance.


I hooked it up to an oscilloscope to confirm that it's not working - the test steps say there should be signal with ~1.5V peak voltage. To my surprise it produced a signal, although there was more like a 3V+ peak, which suggests it is working.

If the sensor is indeed working, it means I need to replace the ignition computer, which equals ££££££££ so I would really like the problem to be the CKP sensor, especially as it's so likely to be disturbed by the gearbox replacement! I hooked the scope up to my 8 valve daily driver, and its CKP sensor produced a similar signal but it was however much smoother. The peaks tailed off nicely. Attached are 2 crudely drawn demonstrations of the traces.

My question is, what should the CKP sensor's signal look like, and is the odd spiky one I'm getting on the 16v enough to cause a no start? The 16v did start once, right after the gearbox was put back in, but then after switching off has not been able to fire since.

Help!

Rus

Attached Thumbnails

   

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190E's:
2.5-16v 1990 90,000m Astral Silver
2.0E 8v 1986 107,000m Black 2nd owner
http://www.maylane.demon.co.uk/190esmall.jpghttp://www.maylane.demon.co.uk/190esmall2.jpg