Quickly,,, and I am SORRY to jump in here like this,,, BUT it has been a loooooong standing question of mine. I have replaced the front crank sensor on my 1990 v12 XJS and I want to replace the rear crank sensor. Is it the same sensor? Although the wire OUT on the rear is shaped/angled differently,,, can I use the same style crank sensor used in the front, on the rear? The cost difference is phenomenal...

Speed sensor,,, crank sensor? How is it even described...?

Any answer will be and is MUCH appreciated.

 

Yes the sensors are interchangeable, not sure about the plug. The wire on the flywheel sensor comes off at an angle to keep it high not sure if it would a problem with the wire coming straight out catching on things.

 

Thank you, Warren!

 

I have checked and with the ignition on, there is no injectors click or voltage at the injectors

 

Hi Sososs

You say that you have resistance on the Front Crank Sensor when Tested with your Meter

Now do the same Test again with you Meter, only this time Spin the Engine while you do it, if the Needle on your Meter doesn't Flicker, then it could still be a Crank Position Sensor problem

Another thing that you could and should try is to remove the Distro Cap and look for any signs of Burning or maybe a Crack in the Cap, either of which could be the cause of the problem

And also Check the Plug and Socket of where the Crank Sensor Plugs into the Loom, just in case the Pins got damaged when putting the New Crank Position Sensor in

If none of that works it might help to get a Noid Light (ebay or Amazon)

 

If the injectors do not click when you turn the ignition on then it could be the following and I would check in this order.

1 Shorted wiring in the V
2 Injector resistor pack and plug
3 No 12V at injectors
4 ECU

Have to go to work now I'll check back tonight once oyu have checked these,

 

I checked the front crank sensor - crank sensor wire disconnected, engine cranking, multimeter had readings of mV - fluctuating

I have done the same with the rear sensor - but nothing on the multimeter; should the rear crank sensor register the same output (mV) as the front one ?

 

could you please let me know in details how to check the 4 points you mentioned ?

 

This problem is most likely going to be either a bad connection or bad wiring. So you need to verify ALL wiring and connectors in the injection circuit are working correctly.

1 Shorted wiring in the V visual inspection- look for damaged insulation, or disconnect ALL the connectors - Every injector and the other end which I think is behind the RH headlight and check the 12V supply wire continuity to ground with an ohm meter it should be open circuit.
2 Injector resistor pack and plug visual inspection, pull the plug out and check the pins for corrosion
3 No 12V at injectors measure with a multimeter


With fluctuating mV reading I suspect you had the meter on DC volts. The meter needs to be on AC. The fact you got fluctuations most likely means the VR sensor is ok.

 

back crank sensor should have the same voltage as front one ?

 

Hi Sososs

The Rear Sensor Monitors the Engine RPM for the ECU

The Front Sensor Triggers Injectors and the Spark

Since I've never had a Rear Sensor go wrong, I am going to have to pass that one over to 'Warrjon' but 'thinking out loud' No resistance doesn't sound good, although the First thing I would do (which has actually worked for me before)

Is to remove the Silver Box Resistor Pack@Warrjon and give the Plug and Socket a really good clean with some Vinegar

Although its a bit of a PIA to get to and remove, you can't give it a proper Clean In-Situ as all those pins need to be 'Shiny Bright' and if it's been on a Buggy, the chances are that it got hammered and splashed with plenty of crud

There are no Shortcuts as a Squirt of Contact Cleaner won't do it, so try that first and let us know what happens

 

My apologies I missed this, yes it should have voltage but it will be different from the front sensor as there are more teeth on the flywheel.

Meter MUST be on AC volts

 

I disconnected and cleaned up all the connections that I found
Measured front and read crank sensors - AC and both had voltage
Checked the continuity of both injector wires to ECU - OK
Checked the continuity of both front crank sensor wires to ECU - plus was ok, but the other - blue wire was not - I could not found a correspondent in the ECU

 

finally the electrician fixed it

had water/moisture in the ECU

 

now I have problems with the 4L80E transmission - with Jake's standalone controller

- with driveline connected - when trying to put on Park is making a lot of noise
- oil come out from the dipstick

please advice

thanks

- l