have a 99 XK8 that I bought from a previous owner as a non runner. The engine would start but quickly stall. The previous owner had bought a replacement ECU and cloned it and it got rid of many spurious codes inc Knock sensors. With the new ECU the codes cleared except for two Evap codes P0453, P0447 and a crank sensor P0336 circuit range code. The car has got steadily worse to the point it will now not start at all. I Have changed the crank sensor but no change. I have continuity from the sensor pins to the ECU pins.

The fuel pump is working and showing 40PSI at the shraeder value plus I can smell unburnt fuel coming out of the exhaust. I am getting between 4-5 volts on one of the 4 pins on the coil packs. The battery is new and well charged but I can't get a spark on any of the plugs.

I have followed the cylinder wash clear procedures (clean plugs put oil in cylinders) as I thought that might be my issue but still nothing.

The version is the newer version for ignition and it does not have the 2 ignition modules like older ones as I understand the ECU does all of that.

Putting the old ECU back in does not fix it either.

I have now spent hours on this and don't know where to go from here except to scrap the car.

Anyone help me ?

Thanks

 

You cannot reinstall the original ECM without AGAIN performing an IMMOBILIZATION SETUP.(only one ECM can be configured to the CAN bus at a time)

Check compression if you suspect 'bore wash'?

 

Thanks for the reply.

Just to be clear even a cloned ECU needs programming each time it is swapped for another clone ? The reason I ask is that I had swapped it around before and the engine ran albeit badly.

if the immobiliser is acting does that only stop the spark whilst still allowing crank and fuel ?

to do immobiliser set up do I need IDS ?

thanks

 

If it starts and runs (even badly) the immobiliser doesn't need to be set up again.
​​​

 

What years had the immobilizer system ?

Z

 

The crank sensor P0336 circuit range code is concerning, but the engine should still start even if there is an issue with the CKPS, since ECU can use both cam sensors as temporary fall-back.

Download the appropriate year electrical guide from jagrepair.com if you have not already. I think the excerpt below is for the UK99/US00 AJ27 engine

Since you only mention a 5V measurement: - the coils should have 12V on pin 4 (PW wire - Purple-White on UK 99, different colors for later years...)


Ignition coil relay - circle 54E 12V power comes from fuse #14 (10A), which is turn is fed from EMS control relay.
Power to coils (square 85) comes from fuse #18 (10A)

So check if you have 12 V on a coil PW pin 4 with ignition on, if not you have an immobilizer/ECU challenge (EMS relay not activated) or a bad fuse/connection, or...
You will have ~5V on pin 3 (SG wire - Slate-Green) but this is just a monitor wire for misfire, and not critical to basic coil operation.
Pin 3 (various colors) is pulled low by the ECU to fire the coil, but you won't see that with a multi-meter.
Pin 1 (B - Black) is ground

 

Camshaft sensor

 

Thanks everyone for the replies particularly Chirpy as he was right a blown fuse on the ignition coils

This takes me back to where I was when I bought the car in that it will start but often takes multiple attempts to get it going. Once going it runs unstable and putting any foot on the accelerator causes it to falter and stall.

On crank I have 40 PSI of fuel pressure but once started it is between 30-35 on a cheap ebay gauge.

Changing the ECU makes no difference and the codes I have are p1648 and P0336. I sometimes get P1648.

I am guessing the only one that would give the symptoms is the P0336. I have changed the sensor and continuity back to the ECU. Could this be a failure of the relucter ring ? Any way to tell without removing the gearbox ?

Thanks

 

I have related this story before about a fellow dealer mechanic that used the crankshaft timing tool the lock the torque converter plate for damper remove/install.

He replaced the timing components and when he started the engine he got the SAME codes you have and the engine ran like $h!t.
We asked if he used the tool to hold the plate and bent the 'flywheel' and he said NO!!!!!!!

He finally removed the gearbox at our insistence and there it was, A BENT TIMING SEGMENT!!!!!!!!!!!!!!!!!!!!!!!!
He went to the parts dept and his cost was about $800. (he was sick)

Another mechanic in the shop said he had a good/used AJ27 drive plate at home and would bring it the next day.(crisis averted)

We teased him relentlessly for days.

DO NOT USE THE TIMING LOCK TOOL THE HOLD THE CRANKSHAFT FOR DAMPER REMOVE/INSTALL!!!!!!!!!!!!!!!!!!

There is another time that a customer replaced the engine in his AJ26 Jaguar with an AJ27 engine.
He swore he had ALL the different related parts sorted (VVT, cams etc.) but could not get it to run correctly.

I FINALLY figured it out...................... He left the AJ27 drive plate on the replacement engine.
He brought me the old AJ26 plate and I swapped it out. Engine ran GREAT.

 

Rough idle.... - have you checked the secondary tensioners are OK?
If not, don't start the engine until you have checked, or repent at leisure.

 

Does the crank position sensor pick up position from marks on the flywheel itself or is there another component ?

is there anyway to diagnose without removing gearbox ?

 

On the 4.2, the sensor is at the bottom of the bellhousing at the front facing edge just alongside the top of a large rubber bung which covers a inspection hatch. I would guess that the 4.0 is the same.

The sensor ring which activates the sensor is mounted to the flex plate facing forwards towards the sensor. Once you remove the large bung, you can see the sensor ring.

I think that the sensor ring is welded to the flex plate so it is all one component. You would only need to remove the gearbox if the sensor ring was broken or damaged and you would then have to replace the flex plate. You will be able to check for damage by looking through the inspection hatch and slowly rotating the engine with a socket on the crankshaft pulley.

Richard

 

AJ26,27,28,33,34 are similar except for a large 'reference' slot in the pattern.(not shown in the picture at the top)

 

I have moved on a little. I followed this test

Q5 : CHECK THE CKP SENSOR SENSE CIRCUIT FOR SHORT TO GROUND

1. Turn the ignition switch to the OFF position.

2. Measure the resistance between EM83, pin 08 (Y) and GROUND.
Is the resistance less than 10,000 ohms?

-> Yes

REPAIR the short circuit. For additional information, refer to the wiring diagrams. CLEAR the DTC. TEST the system for normal operation.


the result was yes I got zero. Does this mean I have a ground supply fault ? Where do I go from here ?

thanks

 

What's the resistance across the pins at the sensor with the wiring disconnected?

 

1600 ohms

 

Anyone know what the voltage reading should be on the signal wire of the crank position sensor when cranking the engine via the starter motor?

thanks

 

I would guess that you're looking for a square wave voltage of less than 3 volts but whether you will be able to see if this varies with a multimeter rather than an oscilloscope, I'm not sure. You could check the resistance of the sensor. You would probably be looking for around 1K ohms so yours seems about right. Depending upon the cost of the sensor, you could just change it if an OBD scan is pointing to that as a potential problem.

Richard

 

Yes. Have you rectified this? Disconnecting the CKPS and measuring ~1600Ω across its terminals indicates a short in the wiring between it & the ECM.

The EG has this to say about what to expect from the CKPS:



... although, as Richard notes, you may struggle to see anything without a scope, particularly at cranking speeds.


But do heed chirpy's advice