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[Kevin Wood]

You can monitor the fuel injector outputs of the ECU, or put a timing light on one of the spark plug leads. Both of these should start to pulse when cranking. You should see pulses at the Tacho output of the ECU (connect an LED with a 1K series resistor if you don't have / trust the tacho). The fuel pump relay should also pull in. If you don't see any of these I would say the crank sensor signal is missing.

You can check the crank sensor output with an oscilloscope. One thing you can do more easily is to check its' resistance. Typically, they are around 800-900 ohms and the last one that failed on me went open circuit. Can't remember which of the 3 pins the sensor is connected across, but you should find 3 pins with this resistance between them.

[RobG]

Pins 1&2 are the "signals", pin 3 is the ground

[philhoward]

Sensor open circuit..   and as the other signs all point towards it, off to find a new CPS..

[philhoward]

OK, now officially confused..

Which CPS do I need?  Its got the "oval" style plug but trying to get the numbers off the sensor failed as its a no-name one but does have the "sloped" edge case of what looks like the Siemens one?  Saw one listed on ebay (Gen GM) but the part number doesn't match with the ones listed in the FAQ about 2.5 sensors (listed as Y26/Y32/X30).

Mine..



Cheers guys...

[philhoward]

Have gone for a cheap'n'cheerful ebay job to see if it does the trick - and I know it won't last...

[philhoward]

Have gone for a cheap'n'cheerful ebay job to see if it does the trick - and I know it won't last...

£25, new CPS and it runs!  Thanks for all the pointers, chaps - now to try and finish the job...