All injectors get +12V from the Fuel Injection Relay with ignition "on". This supply goes to the black/red wires of the injectors. The other injector wires (black with tracers in different colours) go to the ECU which switches these wires to the ground according to the injector firing order. So, you should first check whether the injectors get +12V when you switch the ignition "on". I wouldn't use the the "logic probe" for this but probe (needle) into the black/red wire, connect one side of a small bulb (5W) to the needle probe and the other bulb side to the ground. If the bulb lights bright, the supply to the injectors is good. In any case, check the Fuel Injection Relay located inside the ECU compartment:

 

Ok. The rubber hose section of the fuel return line inside the tank (thanks M. Stojanovic for confirming what that was) definitely needs to be replaced. Its still connected but is deteriorating. Of course this wouldn't cause my issue but I'll replace it at some point in the mean time. I didn't get back to the car last night so I'm gonna go try the bore wash procedure a couple more times. Will update...…..

 

So I tried the bore wash steps 2 more times with no success. The car then felt pitty for me and decided to throw me a bone. There had previously been no codes except for when I had a sensor unplugged or relay out. Once all was plugged in theyd go away. The bone she threw at me was a P1336 - ckp/cmp synchronization malfunction. I did by the factory service manual so I now have a bit of steps to help diagnose. Haven't looked for either sensor yet but I'm assuming CKP is near the harmonic damper and CMP is on top of one of the heads. Well see.

 

Hi Everyone,
It seems like there is always at least one thread going here about one of the Jags that suddenly won't start or starts briefly then won't go on. I have a suggestion, let's call it a request, that comes from having a GM beast that barely ever gave trouble like that. Not just once, but, three times out of my carelessness and slow learning it did briefly die after all!!
The Jags are almost as if they're specially made to check this possible problem first, super easy before all hard stuff. If the car ran fine last time out and now won't even start-or not for long- skip the spark plug removals and all the relay checks at first. As a first step, tap the fuel rail Schraeder valve for fuel pressure. For second step, make sure the pressure is fuel--not water! In frequently humid climates it's amazing how ignored dry gas needs can sneak up on your car. ISOPROPYL alcohol, not ethanol--ever!!
As you look at many of the "suddenly won't start scenarios" posted here you can easily see how water could/would lead to soaked spark plugs leading to affirmative check of spark voltage(but, no spark on the soaked plug), then manual gas/liquid dynamite addition, maybe fires once or twice, then bore wash needing oil to reseal, etc, etc. The scenario fits pretty, but, maybe not often.
So, as a first step on fuel pressure check at the Schraeder, make sure it IS fuel!! Maybe you'll get lucky and find with a simple parking lot check, that the cure is really easy!! With fuel back into the plenums, it will crank a bit then fire, spit, hiss, belch, and clean out the rest of the way with compression heat--if that was the problem!! Real possible! Occasionally the cause.

And, don't forget to give your Jag a hug each time it brings you back home!!!

 

The CKP is at the bottom of the bell housing, accessed from the space between the steering rack and the engine side of the bell. It is next to the opening for access to the torque converter bolts. The CMP is on the LH cylinder head, at the top rear inside corner of the head. Its connector should be clipped to a bracket attached to the throttle body.

When I bought my Super V8 (4.0 SC), it had problem with starting but it would always start and run well if I, before cranking, keep the ignition "on" for some 40-45 seconds. Later I fond out that the CMP was missing - actually, its plastic head/bracket with the pigtail wires and the connector had been broken off by some PO's previous work on the engine and were missing; only the metal body of the CMP with the o-ring was still inside the head. The reason why the engine would still start (after 45 sec. ignition "on") was the Jaguar's "fail over" feature - if the CMP is non-functional, the ECU will switch over to calculating the cam timing from the CKP signal but it needs some time to realise "no CMP" and to switch to the CKP (thus the 45 sec.).

You can try this 45 sec. method and the engine should start if your CKP is good. If it does not, then the CKP is the main suspect.

 

Excellent. Will do and update. We're close, she'll be running soon.

 

Forgot to mention: If after 45 sec. the engine still does not start, unplug the CMP and try again. If still no start, replace the CKP first and try again without the CMP and, if it starts then connect the CMP back and see what happens.

 

what I feared would happen when going down the bore wash route on a car of this age has of course happened. Located cmp and ckp, pulled both connecters to inspect and clean them. Plugged in ckp, left cmp unplugged, attempted to start and of course no start. Near the end of that attempt the starter began sounding really rough. I knew then that was it. The next attempt to start I got nothing but a click. Tried tapping it with a hammer and nothing, So now I have a starter to replace in addition to all this mess.. Safe to say Im pretty furious and about done with this car

 

if anyone has the part#s for the crank and cam position sensors for the 99 XJR Id appreciate. Guess Ill just replace both while I do the starter. I've heard stories of wrong parts coming from rockauto and others so part #s would help. I'll also see what the dealer is willing to tell me.

 

The Crank Sensor is AJ81284 and the Cam Sensor should be LCA1646AD. Just in case, since there are two types of Cam Sensors (having only different connectors), check what connector is on the pigtail of your Cam Sensor and compare with the pics below.

LCA1646AD


LRA1646BC

 

thanks, mine is the 2nd one. I appreciate the help

 

Been a while since an update. Finally got the new starter in and new CKP since it was at the bottom also and pretty easy. Reconnected battery and tried to start...........no Start. The 1336 code was still there. Connected CMP which was still disconnected and cleared codes. Tried to start and no start. Code did not come back. Ran thru bore wash procedure and no start still. No codes other than p1000 obd2 readiness not complete which is normal i believe. Back to square 1. No start, no codes.............sure, I'll try the bore wash steps again. Other than that..................

 

The P1000 is because the car did not start for the ECU to complete its cycle of testing. So yes, that would be considered normal.

Ok, I don't want to muddy the water more than it is, but in this thread... https://www.jaguarforums.com/forum/x...-spark-149361/ ...Don makes an important statement and its a statement I've also read regarding older 308's. That being, if the voltage to the ECU is below 11.4v (Lady Penelope was voltage specific in his thread response) it will not fire the ignition. He also makes a point to check the ground and a procedure check in Post #4 on checking the Tach to see if the CKPS is functional.

 

Thanks Highhorse. I'll def take a look at it

 

As I understand, the voltage of a good battery will normally drop to some 9.5V-10V during cranking. I don't think the Jag's ECU would not fire the ignition at any voltage below 11.4, otherwise we would have a lot of starting problem, especially in cold weather when the battery voltage drop is even higher.

A couple of days ago, I took the battery voltage measurement just before starting. It was 12.0 V and it certainly dropped well below 11V (probably 10V or less) while cranking but the engine fired up straight away.

 

For sure we'd have many more posts and "common jaguar knowledge" if you will, if the ecm does not fire the plugs at all under 11.5 v. In any case I keep a batterycharger on it. I make sure the charger is on and charging a small current whenever I'm cranking so that isn't an issue. I will see if my tach displays anything. It should since the CKP is new. Then back to checking for spark, if spark is still there we'll go back to verify fuel is still there. If they both are then we'll go back to bore wash as a cause. Seems I'm going in circles. But I'll update later.

 

Did you check the injector relay (inside the ECU compartment)?

 

Yes injector relay was swapped with a known good relay and no difference was observed. That was a before the bore wash and starter failure. I will check it again also. As an update on current situation. Checked for spark and It has a really nice, strong spark. The CKP is new, and 1336 code has gone away. I want to rule out the bore wash idea finally so I pulled the plugs again and squirted a bit of oil in each cylinder. I'm pulling the fuel relays to be certain no fuel is added and im gonna run through a few startup cycles. I figure that with the oil I put in the cylinder should certainly cure any bore wash. This thing should start after that. Everything else checks out

 

Did as stated above. No start. P1336 decided to show up again so Idk. I have the CMP so may as well replace it. We might be nearing the point of having to tow this thing to the Jaguar specialists...........

 

I do not have personal experience with it and I was simply providing another post regarding the issue at hand. Don has pretty good experience and I trust his statements. But your stating a circumstance all starters are drawing the same amount of energy, which we know is untrue with all heavy draw electronics as they age. It very well may not be the issue, but simply, its something to check and determine as a cause or eliminate as not.