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        General >> Problems >> Crank Position Sensor - Function/Replacement
        
(Message started by: SteveS on May 11^th, 2006, 7:27pm)

Title: Crank Position Sensor - Function/Replacement
Post by SteveS on May 11^th, 2006, 7:27pm

Hi All,

I have a running topic "2.9 24V Cosworth wont start" and this has led to some additional questions I was hoping you could help me on.

I think I may need to replace the Crank Position Sensor but the second bolt appears to be behind a "tension pulley" which I cant get to.... Does any one know of the easiest way to change this or verify it is working or not....

My OBD11 scan shows no error codes (using Digimoto software and ELM320 interface)..... I have changed the DIS Coil pack, the ignition transformer capacitor and the Electronic ignition unit but still get no spark so the Crank Position Sensor is about the only thing left.....

Should the OBD11 scan show an error code if any of these components have failed or does the engine have to be running to get error codes?

I am still a Scorpio and OBD newbie.... but hope to get better soon.

Thanks in advance,
SteveS

Title: Re: Crank Position Sensor - Function/Replacement
Post by Simmo on May 11^th, 2006, 9:47pm

Does the appropriate link on this page help. http://www.fordscorpio.co.uk/emmanuals.htm. This also may help. http://www.fordscorpio.co.uk/htcircuit.htm.

Title: Re: Crank Position Sensor - Function/Replacement
Post by sector-9 on May 11^th, 2006, 10:25pm

The ECU can tell if there is an electrical fault with the sensor or it's wiring such as open or short circuited. It cannot tell if there is a mechanical fault such as the sensor not being close enough to detect engine rotation. The ECU uses the crank sensor to tell it that the engine is spinning (so to inject fuel and spark), and I believe the rev counter.

The fact you're getting fuel injected into the cylinders suggests that the ECU knows you are cranking the engine, and probably means the crank sensor is fine. It works in the same way as an ABS wheel sensor and can be checked using a multimeter set to measure millivolts - should get a definite reading when the engine is turning over.

Darren

Title: Re: Crank Position Sensor - Function/Replacement
Post by SteveS on May 12^th, 2006, 4:15pm

Thanks Simmo and Darren,

I have removed the top radiator hose and examined the loom... which was a bit rubbish...

Found the insulation on the two leads going to the CKP were chaffed and probably shorting.... Separated the two wires and cranked the engine and still no spark BUT this time the OBD11 reading for RPM showed 200 during the crank cycle......

So I am assuming the sensor is OK and feeding data to the Electronic Ignition unit.... So it's not the sensor.....

But the good news is I now have a brand new spare one for the future.....

Thanks Chaps,
SteveS