Hi all,
My car is a 1996 4litre with a Liquid Petroleum Gas kit fitted. Will start on LPG or gas (petrol).
Came on here back in December to check out why my XJ came to a sudden stop.
General consensus was the crank position sensor.
I did the cps test from:
http://troubleshootmyvehicle.com/jee...crank-sensor-2
I had the 12volts and the earth but no alternating 5/0 volts when the engine was hand cranked.
No engine check codes, no problem with the gauges.
No spark.
I had an auto electrician look at it and he declared the cps dead.

Took the old one off. The part number on it was: 56027865ab.
Ordered a new one from Fleabay.
Emailed the seller to check and he said Yep - that's the right one.
The new one looked the same and had the part number inprinted on it. The connector was a tough fit and had to be filed down to fit. (I took that to be a cheap Ebay part)

Fitted it but still no start,
Auto electrician came back - this time could find no signal to the coil - but declared the cps ok. Said maybe the CPU is not functioning properly.
Had a strange clicking from various sensors around the engine bay, I thought maybe there was a short.
Dismantled and unwound dodgey looking sections of the loom - including a bare section going down to the O2 sensor and engine temp sensor, Everything looks ok otherwise - couldn't find any shorts.
Sent the CPU away to be checked. Came back OK except a fault on the charging circuit (which there was no sign of before). Repaired.
I then checked the cps again - no alternating 5/0 volts signal, jut constant 5.
5 volts being sent to it, and 12 and ground.
Just checked the part number (56027865ab) online and it seems to be the one for a 2.5 litre.
I thought it might be the CAMSHAFT position sensor even though there's no signal to the coil - that's my next test tomorrow.
Question is:
Where do I go from here?
Do I buy another same part number if the cps is at fault?
Do I buy the correct for my car?
How did my car run with the incorrect part?


Suggestions please.

 

That is the part# a Jeep Dealership gave me for my 1996 XJ based on the vin#. They are on backorder with Jeep. Jeeps are finicky when it comes to oem sensors vs aftermarket, but I think you have the wrong sensor if it didn't fit. I would search for an OEM Mopar sensor before swapping out a bunch of different parts. Here is a link to my recent experience with the CPS... https://www.cherokeeforum.com/f2/ran...-today-204215/

 

After market CPS's are known to be bad right out of the box and if theu do work they normally have a short life span. As Bruce has mentioned an OEM sensor is the best way to go. If you can't find an OEM one pick one up from O'Reillys Auto Parts. Also the testing of the CPS is a bit sketchy at best. I have had several bad ones test good and still be bad.

 

You also have a cps in distributor .....Cam Position Sensor will also cause no spark either one should throw a code if faulty . Did you read the codes ?

11 No crank signal to computer. Fault in wiring between crankshaft position sensor (CPS) and ECM ( PCM or computer ) or faulty CPS.

 

Back again.
Still no start.
New CPS fitted.
New OE crank position sensor fitted.
Spare good coil fitted.
No codes - just 12 and 55 (battery disconnected and finish codes)

Very frustrating.
Any new ideas?

I'm thinking of taking it (somehow) to a main dealer (Marshalls Cambridge UK), do the main agents have better diagnostics kit?

 

I would swap around the relays in the relay box under the hood,

and also you would want to closely inspect the wiring going to the O2 sensor..look for hot spots that may have melted the insulation and causing a short.

Now I do not know if this actually works or it is coincidence. After I replaced my CPS I tried to start it. It turned over, but did not catch. Now being frustrated, I walked away from the Jeep after it didn't start. Later I went back and realized that I did not turn the key to off and had actually left it on. About 15 Minutes had passed. I turned it off, and then tried to restart it and it fired right up. Take free advice for what it is worth...but I hope this helps..

 

Some mini fuses are crucial. It happens that some oddball short, say a rear o2 wire can pop a fuse and take out the ASD relay. #17 #19 21????