Further to my efforts to troubleshoot the no start issue on my girlfriend's car I'd like to figure out if the CPS is working OK.

In searching the forum I've seen references to testing the CPS but no actual description of how that's done.

I'm assuming it's a matter of checking resistance across the sensor with an ohmmeter? Could anyone describe that test and what the reading should be?

Thanks!

 

download this book. It is the bible for those engines.

AJ6 4.0L Engine Management System Diagnostic Guide.pdf

 

Thanks Mark! Just what I was hoping for.

 

You're welcome. It is posted here in the sticky section. Lots of good info there as well. Post what you find, if you can.

 

Did you find what you were looking for with this issue?

 

The manual that Mark directed me to describes a test for the CPS that involves checking resistance. This is from memory but I think it's supposed to be 1.35 Ohms. I'm waiting for a day when it's not bloody cold or pouring rain to check the one on my girlfriend's car.

 

Do you have a junk yard nearby that may have a 89-94 jag? Go pull one out and install it in your car, if it doesn't start it is probably something else.

 

No junkyads close by but if it looks like the sensor is shot I'll just buy a new one.

You guys will love this question but how the @#$% does the connector come off that thing??? Not a lot of clearance to get a hand in there but I've been prying and pulling and it doesn't budge! Looking at and feeling it there doesn't seem to be a release or anything to get it off. What am I missing? Do I just have to pull harder?

 

Hello Everyone This is my first post here. I am currently working on my friends 1993 XJ40. The car doesn't start. I've checked the fuel and ingnition lines and circuits and they all seem to be fine. I've checked the CKP sensor and my multimeter showed an open line. The resistance should be obout 1,35 kOhm. I believe the sensor is dead. I am going to replace it asap. Unfortunately, I don't have an osciloscope, to be perfectly sure. I apologize for my english. U can point my mistakes, so I will improve in the future

 

Welcome to the forum guciu1801,

Your English is excellent. Your XJ40 checking is also careful.

It's a few years since I had an XJ40 but, as I recall, the CKP on mine just died without any advance warning of failure. Experts here will jump in if there's any further tests to run before replacing it.

Please post in the New Member Area - Intro a MUST and introduce yourself and your friend's XJ40 to all the members.

Graham

 

Looks like I may have the same problem. No start and, I've checked everything else (I think). Bought a new one, will install, early next week and post the result, if any.......Roger.

 

My 93 died then wouldnt start,after going through testing everything including the rotor which all tested within spec,tried a new rotor and started up and is running fine. you may want to try a new rotor as the same thing happened to my brothers 81 about 30 yrs ago and it also was the rotor.

 

Are you refering to the starter motor rotor? It's not that, because the engine cranks fine (untill the battery is good :P), there is no spark and as far as I can see, there is no fuel flow. I was thinking about the alarm, because of the red light on the dash, but it doesn't glow or flash... or anything . I will have the new sensor by the end of the week.

 

I think you are referring to the distributor rotor? I've swapped out that and the cap, no change. It's worth a try though.......Roger.

 

Yeah, I didn't think about the 'distribution rotor'. I've looked at it, and cleaned it up a little. Is it possible, that clean rotor and distrubutor cap, that are in "not so bad" condition could prevent the car from starting? It's all clean and dry, the ignition coil resistances are within parameters. I sure hope it's the CKP, because it costs over 100$ here original part from JAG dealer.

 

On my car the rotor had continuity but still wouldnt create any spark,put a new one in and started right up. on the old rotor I then proceded to take the orange sealer that was between the brass parts,there was a material that looked like what they use in plug wires it wasnt broken but it wouldnt pass enough amps to fire the plugs.Sort of like when a wire with a fuseable link fails.

 

Hi, OK, fitted the new crankshaft sensor, started right up and, runs well again.......Roger.

 

Good news for you Roger.

Re-reading the thread, it's looking increasingly like guciu1801 is going to have to go the same route.

Graham

 

It's alive sensor replaced, car is up and running again Exhaust manifold gaskets appear to be blown. Some more work. But the engine itself runs fine The sensor's resistance is 1,4 kOhm. Measured between red and blue cable.
Thanks for help, especially for the "big book of XJ40 science"

 

Can you advise me what voltage there should be at the crankshaft sensor on Jaguar 4 litre.
Ta!