Ever since having the timing chains and heads redone on both banks (after a break of the secondary chain on Bank 1), I have had OBD readings P0305 (misfire, cylinder 5) and P0341 (generic definition: camshaft position sensor range issue, bank 1).

My mechanic and I, after reading some posts here and elsewhere, went with the following cylinder configuration for misfire diagnosis:

Bank
1 2

7 8
5 6
3 4
1 2

Front

This also made sense, since the standard OBDII definition for a P0341 code is for the Cam sensor in Bank 1.

Long story short, swapping/replacing coils and spark plugs all along Bank 1 made no difference -- the same two codes keep coming up (and with typical misfire symptoms). The next step this Monday was going to be to replace the Bank 1 cam sensor (which is consistent with the generic definition of a P0341 code).

But I spent some quality time with the JTIS tonight, and concluded that we may be concentrating on the wrong bank. There seem to be numerous opinions on this board about the cylinder numbering for purposes of OBD readings, but based on the DTC section of the JTIS, I am now going with the following for my 4.0 litre V8:

Bank
1 2

4 8
3 7
2 6
1 5

Front


I base this on looking up my P0305 code in that section, and it is described as a misfire in Cylinder 5, which is then described as "2/1 V8". This would be consistent with the 1234 front to back configuration for both Banks 1 and 2 that is found in various diagrams.

Now, the other thing that is interesting is that Jaguar's description of code P0341, in contradiction to the generic definition, is defined as being a problem with the cam sensor in Bank 2 as opposed to Bank 1. This is consistent with my reading of the cylinder numbering, as I'm assuming the cam code is probably being triggered by the misfire (rather than the other way around), but either way it makes sense they'd be in the same bank.

I guess I'm just looking for validation before I go back to the mechanic on Monday and tell him we've been concentrating on the wrong bank entirely! Should I ignore common wisdom, as well as the generic OBD definition for P0341, and go with my hunch here?

 

I believe the diagram in post #3 is correct, so your second scenario would be correct

https://www.jaguarforums.com/forum/x...001-xj8-34571/

This subject still confuses the crap out of me, I'm used to decades of GM V8 numbering which has a different convention altogether

 

The numbering is well described by jag and you were indeed using the wrong one (which is for later cars, with the 4.2).

All the jag documents (such as electrical guides, Vehicle Specs, JTIS, Tech Guides, TOPIx) I've seen are careful to get it right but of course you have to look at the ones for your engine and year and car model. Make sure you've looked up the P0 (or other) codes in the same way and you should be fine.

 

Thanks Mikey and JagV8. This makes me feel a bit less confused! I think what was throwing us is that the generic P0 definitions are just ever so slightly off. I've printed out the codes for the 2000 MY and will only use those definitions now.

 

There's extra info in there, such as possible causes, too.

 

Went through those, listed under the P0300 code, and my first thought was a bad coil or incorrect plug gap. But on a hunch my mechanic tested the fuel injectors on 5 and 6 (now that we have the correct numbering) and found them to be quite wide apart resistance (can't remember which one he said had more and which less). He switched them and cleared the codes just to see if we would get a misfire code on 6 instead of 5. Unexpectedly, we get neither and the beast runs beautifully! I picked her up tonight and put her through the paces on the freeway (where the misfiring was obvious before, and where the check engine light would flash), and all went smoothly, even when I punched the pedal forcing two downshifts in "s" mode. No CEL and whe also idles beautifully. I'm guessing it was just that the connection to the injector on No. 5, though that doesn't explain the difference in resistance. Either way, all's well that ends well -- especially as the mechanic was really worried that maybe he'd messed up valve seating or timing while the heads were out.

 

Glad to hear that it all worked out.

 

Many codes don't set for 2 warm-ups so I have my fingers crossed that all is well!

 

Don't feel lonesome............

Because cylinder designation is such a crap shoot, depending on what technical information you are looking at at the time, they made these available. Helps immensely!

Cheers,

 

Well, the CEL came back on shortly after JagV8's post, but not the same codes. Instead I get a new code -- P1388 -- VVT retarded on bank 2. The car is still running great, though. My mechanic changed the oil as part of the top end rebuild follow-up the same day that we seemingly resolved the other code and misfire issues, so based on threads here I've decided to focus on oil feed to the VVT actuator. I've added a bottle of STP to up the viscosity (their liberal handout of cool stickers in the late '60s and early '70s finally netted them a sale!). I reset the light and figure I'll know after a couple more start ups whether this helps...

 

Here is a diagnostic TSB that might help.

bob gauff

 

Bob - that doesn't seem to apply to his model year & engine

 

Yes I see that the car is a 2000MY..
sorry..
nevermind

bob gauff

 

I think the diagnosis would be similar, though, between years, despite differences in cylinder numberting, etc....? As an update, teh P1388 code has now been joined by the return of the P0341 code. No misfire codes (or actual misfires), though, and still runs smoothly and seemingly at full power...

 

With P0341 the bank 2 CMP signal or sensor looks to be faulty.
And the codes PDF says VVT is inhibited (i.e. turned off).

I'd be looking into the P0341 but especially wiring and connectors all the way back to the PCM as a chafed harness might be the cause. I wonder if signals relating to P1388 share any of the same harness?

 

Thanks, JagV8 -- I was thinking along the same lines since the P0341 code had also appeared previously. It is odd that there was no P1388 when I was having the P0341/P0305 combo.

Perhaps on a side note, my battery has been somewhat wonky since I got the car back, with a bit of hard starting in the mornings and some mild squealing from the alternator until the car warms up. Do you think a bad battery/low voltage could be contributing to the codes being thrown? I've seen other threads indicating that a bad battery can lead to such things...

 

Beats me, but it's a simple thing to change and compared to most things quite cheap.

 

Well THAT was a help!!! I had a 0305 and changed the coil for what I thought was #5. Same problem persisted and was worried it was something more major. I have the "alternate" order on my 2000 JX8 VDP, and changed the right #5. Now she purrs again!!! Just have to fix an errant wiper that doesn't know when to quit (I'm changing the relays first, much cheaper start).

 

The good thing about standards is there are so many to choose from
and you can always hang on and some more arrive!