XJ 2.5TD Wont start, immobiliser issue

[agwhiteb0i]

Alright so my nightmare of an xj has had this problem and has not been movable for almost a year now.

The Problem:

The problem occurred one day when getting into my car at a shop and going to start it, once putting in the key and turning it, it started but would turn off after about 3 seconds. I noticed the flashing NO KEY light even tho the key was present. I had minor occurrences before this where the car would not start, but after a few tries it was fine and where it would suddenly turn off going 60 on the road with the NO KEY light flashing (restarting the car would make it fine to continue driving)

Things Done:

So i have tried ALOT. I am basically at the point where im about to sell it as is, it has been to 4 mechanics and a sparky, its has had new immobilizer units, new keys and barrel along with an 2 entire new ECU's, but still no fix. Have had multiple mechanics try and bypass the immobilzer in the ecu and try and reprogram new keys and what not, still no go. It sat at the sparkies for quite a while and im not too sure myself how much he actually did but also returned with a no go.

Have spent alot of money on this shitty problem and am not much prepared to spend more, but basically wanted to know if ANYONE has run into this or if anyone had any ideas? my thoughts for a while has been possibly a silly ground fault somewhere but just dont know anymore.

[amlav]

Could have been just a dry solder joint in the old imobiliser module or ECU connecting pins on circuit board .... or broken wirring .
As far as I know the imobiliser sends signal to PCM/ECU and PCM enables engine to start.
Not sure if signal is sent on the bus system .If it is PCM would expect a binary code from imobiliser .Stand to be corrected on this ...
New ECU's have to be reprogrammed if that would be the case ....again just assuming .
Maybe somebody else could help you more on this one ..

[jaffazoom]

Pretty much covers it.

Yes they talk to each other over the CAN bus.
Most likely a wiring issue but locating it is the problem.
The wiring is getting on in these things now and would be a nightmare to sort. The new cars are not going to far much better as they put more and more of this stuff into them.

On a side note if it were in Brissy and in good nick I'd be interested in it for my Mitsubishi 2.8 diesel swap (doesn't need all the electronics).

Best of luck with it but it obviously isn't an easy fix.

[agwhiteb0i]

Originally Posted by jaffazoom

Pretty much covers it.

Yes they talk to each other over the CAN bus.
Most likely a wiring issue but locating it is the problem.
The wiring is getting on in these things now and would be a nightmare to sort. The new cars are not going to far much better as they put more and more of this stuff into them.

On a side note if it were in Brissy and in good nick I'd be interested in it for my Mitsubishi 2.8 diesel swap (doesn't need all the electronics).

Best of luck with it but it obviously isn't an easy fix.

Thanks for the reply guys, yea i have figured as much as a wiring problem somewhere, i have read alot about the SKIM unit gettings its power from the same circuit as the rear wiper and tail lights, but both these are working fine, the grounds on the skim harness are in good continuity with a good ground and the voltage on the B+ lines seem to be correct.. starting to check at the wires up in the roof overhead cluster now for any wiring faults.. also been delving into SKIM bypass through a few american companies but not sure how costly this would be...

Also funny enough i am in brissy and she is in awesome condition (which is why i am so dissappointed) so shoot me a message jaffazoom if you're interested for some more details

[Mudmonster]

has anyone plugged it into the DRB3 to check what is going on in the computer if there is any codes etc??

check the wire in the back corner of the drivers side engine bay just before it goes behind the overflow bottle, I had an issue where my wires had rubbed and worn through and would make the car play up,

[agwhiteb0i]

Originally Posted by Mudmonster

has anyone plugged it into the DRB3 to check what is going on in the computer if there is any codes etc??

check the wire in the back corner of the drivers side engine bay just before it goes behind the overflow bottle, I had an issue where my wires had rubbed and worn through and would make the car play up,

Thanks for the reply checked this out, opened the loom on this entire side leading to the ecu, to my disappointment the wires were in really good condition, couldnt find any possible extensive wear so id say i'm looking at the wrong spot..

Does anyone know much about the fuel cut off solenoid? before my car used to start and turn off after 2 or 3 seconds but now it just keeps cranking. I have read the the immobiliser possibly shuts off the fuel? iv also read this is just a safety feature that cuts the fuel off in security mode and can be turned off by unlocking either the tailgate door with the key or the passenger door etc.. none of this did anything though

Just as another note, on a forum i was reading, a guy with a very similar problem was having the same "car turns off around 60 clicks sometimes randomly or around corners" which people where saying was linked to the fuel pump, any chance my fuel pump could be knackered? i have taken the line off the fuel filter and cranked the car but nothing comes out? i have also checked the ASD solenoid which is working fine (have even shorted pins 37 and 80), or is this again due to the immobiliser just cutting the fuel off..

[amlav]

Originally Posted by agwhiteb0i

Does anyone know much about the fuel cut off solenoid? before my car used to start and turn off after 2 or 3 seconds but now it just keeps cranking. I have read the the immobiliser possibly shuts off the fuel? iv also read this is just a safety feature that cuts the fuel off in security mode and can be turned off by unlocking either the tailgate door with the key or the passenger door etc.. none of this did anything though

Just as another note, on a forum i was reading, a guy with a very similar problem was having the same "car turns off around 60 clicks sometimes randomly or around corners" which people where saying was linked to the fuel pump, any chance my fuel pump could be knackered? i have taken the line off the fuel filter and cranked the car but nothing comes out? i have also checked the ASD solenoid which is working fine (have even shorted pins 37 and 80), or is this again due to the immobiliser just cutting the fuel off..

Maybe if ECU doesn't gets the right signal from imobiliser it just shuts down
all supply to crankcase sensor and fuel solenoid after a few seconds .
If no signal coming back to ECU from crankcase sensor I would think engine just cranks but nothing to tell it when to open the injectors .
As far as I know there is no fuel pump on the diesel xj's just injection pump .
So the simplest way to check would be to crack open one of the injector pipe and see if anything squirts out . Just be carefull ...fuel pressure is verry high.