Could be an automatic: the 4.0L cars got the electronically-controlled ZF 4HP24 transmission, but the 2.9L, 3.2L and 3.6L cars got the hydromechanical ZF 4HP22, which uses a kickdown cable instead of a switch.

And a lot of us enthusiast drivers would take issue with the idea that a car cannot be "fully loaded" but have a manual gearbox....

Cheers,

Don

 

Although you've told us your car is a 92MY, I haven't been able to find the VIN number anywhere in this thread ..as there are two different CPS sensors depending on VIN#, is it possible you MIGHT have the wrong one fitted?

To VIN 629285 - DBC2139
VIN 629286 on - DBC11501

Just another shot in the dark

Larry

 

Wasn't the manual transmission an "optional extra"?

(Can't imagine why anyone would want one though )

Larry

 

That's right Don, I forgot about that kickdown cable. And I completely agree, I'd love to have a manual in mine!

 

This one is the 3.2l automatic.

Not sure if there is supposed to be a switch there or not?

It is not mentioned in the workshop manual.

Keeping in mind this is more of a xj40 [aj6] than a xj6 model.

 

Being the 3.2l it is definitely the hydro mech Automatic gearbox.
No full throttle switch as a result.

-

Had a DBC11501 fitted when I replaced it.
Had the smaller connector fitted at the time too.

-

Not much hope in sight recently, still trying to come up with new ideas.

 

Update;

So far still nothing has shown up to cause any concern electrically. The entire wiring harness regarding the ECU is ok, and showing connectivity and continuity throughout.
This took significant effort and time to check over 2 weeks.

-

Tomorrow I am going to inspect the timing chains again with reference to the CPS, and TDC. Permitting I hope to have enough time to make a video of the timing problem.

List for tomorrow; weather depending.

1 -Remove cam cover and inspect relationship between cams and TDC [This was already done 2 months ago, but does not hurt to be double checking.]
2 - Check TDC and the CPS marker positions.
3 - Remove the distributor and check the tensioner.
4 - Refit the distributor checking alignment marks, even though this ultimately is not a precision exercise as with conventional distributors.

-

So in general, I am still not very optimistic about a positive outcome.

The only things that I can think of at this point is that the crank to cam chain has slipped. However, this does not explain why it idles well and starts reliably. Nore does it explain why the car advances its timing in the wrong direction, causing backfires after TDC about 20-30deg.

-

Still hoping for a good outcome

 

Have you moved the distributor? There have been instances where it has been moved and as the engine speed increases the rotor moves in relation to the point that the gap from the rotor to the pin is too far for the spark to jump, causing the rpm to stall at a certain rpm.

 

Have re-installed it using the workshop manual specifications, also worked perfectly last time I did so.

-

Busy day ahead today, working on it all day in search of just about everything.

 

Have you thought about trying another ECU, that's about the only other thing that I can think of that's going to effect the timing? I managed to fry one on a banger that I purchased to do a charity run from Auckland to Invercargill. I reverse connected the battery cables, not once but twice, I think I must have been getting really frustrated at the time.
That managed to fry a few things inside

 

Update; so today there is nothing to remark, everything investigated was mechanically stable, timed correctly and no timing chain slippage of any kind was recorded.

New intake manifold rubbers arrived today and this resolved an issue of a pinhole in the throttle body gaiter. But this did not do much at all, for improving overall performance. The engine still can not make it past 1k rpm.

-

Tomorrow, I am investigating a discrepancy between the aj6 manual and the car. There is a stepper valve, and there is also a supplementary air valve located somewhere in the car ?

I am also going to remove the LHS wheel and investigate the carbon purge canister. Reportedly there is a purge valve there, but I have not removed it and checked it yet. Only via proxy with a multimeter. Also its electronics, that partly checkout. Having not sussed it out in depth before: I may find something out.

The purge valve, and the supplementary air valve, may be the same thing?

-

With reference to Robman25 - the car has already had a new ECU put in. It made no difference, so I assume that I have two working ECU's. THere is just a fault somewhere.

Your suspicions are very valid, this was thought to be a fix. So we went to the trouble of procuring one and replacing it. Turned out not,...

-

In summary for today, there are two options remaining to investigate. Try another CPS as suspicions always mount heavily on these. Then continue to trace and test the (purge/sup air) valve.

 

I would also check that you have the correct CPS mounting bracket for your 3.2 engine - AFAIK these brackets are not interchangeable.

Larry

 

Hi Terry,

I recall that you were going to have the exhaust pressure measured - were you able to rule out an obstruction in the exhaust, such as a clogged catalytic converter? If not, you could test this by disconnecting the EGR valve and exhaust manifolds and pulling them a couple of inches away from the head and running the engine. Just don't do this in the middle of the night or you'll give sleeping neighbors a fright.

Cheers,

Don

 

After today's intensive lookover, I have a question?

What is the acceptable clearance or workshop requirement between the CPS and the reluctor wheel?

I tried to measure mine today; would need to measure it in mm!

There is a definitely visible gap. approximately 2-3mm.

-

Regarding the question of the correct CPS mountain bracket. It has the original one in it. Though a revised bracket is under a current purchase order.
The part numbers match those listed for sale in the category for this vehicle.

-

All other observations and tests today came up negative.

This included a perfectly functioning (purge valve/supp valve).

-

Summary;

I will be researching today what the acceptable clearance is for the CPS. In extension to this predicament, I will also try to find out if there is any size difference between the early and late CPS sensors. Including the original one, should it still be on the tool chest and not disposed of.

My theory is that at low revs the CPS can handle the idle speed. When revs are increased the CPS signal becomes distorted and the ECU can not make out what to do. Currently, a .5m spacer and a 1m spacer have been enough to cause rough idle. Which would suggest that there is a problem with the clearance.

 

Hi Terry,

I haven't pulled out the Jaguar Workshop Manual DVD-ROM, but according to pdf page 117 of the Haynes manual, the gap between the CPS tip and the reluctor ring teeth should be between 0.46 mm and 1.07 mm (0.018 in. to 0.042 in.). You can measure the gap with a standard blade-type feeler gauge.

I can't think of a reason the CPS would provide a distorted signal at higher revs unless the sensor or bracket were not securely fastened and were moving in relationship to the reluctor ring.

You can download a scan of the U.K. edition of the Haynes manual at the link below. It's missing a couple of chapters, but the rest is there and a great reference for XJ40 owners:

Haynes Jaguar XJ40 Repair Manual

Cheers,

Don

 

So my vin number is a bit confusing - remembering it is a 3.2l modle, Exported to Australia.

SAJJFALG3AJ663883

So I am wondering about the part numbers for the CPS.

There was a DBC11501 style connector fitted at the time.
So I replaced it with a new one of these.
I am not sure if the dimentions are the same.

However; there is only 0.2mm differance, shorter between the one installed currently.

-

Aside I am looking to get the clearance issue sorted shortly.

Hopefully all I have to do is loosen and re-tighten the bolts.

-

Still largly flying blind on this one but at least it is something not to specification !

At least it will give me something to fuss over,...

 

Managed to reign it into .90m

1100rpm - most improvement in 3 months,...

 

Is it possible the sensor isn't installed properly in the bracket or that the bracket is faulty in some way?

Larry

 

The bracket was taken out and inspected for faults, noting that can be seen with a normal eye at least. The sensor now sits within its clearance specification at least. Made little to no difference though.

Not sure if you can possibly incorrectly install one of these? Very straightforward process.

1 electrical connector, 1 machine screw; Old out, New in.

Might just be a faulty one,...

----

Might just get another DBC11501 before I give up.

Can not possibly be anything else.

 

Hi Terry,

It may be possible to install the crank sensor bracket incorrectly because there are hollow locating dowels that fit in recesses in the timing cover and bracket which determine the correct alignment of the bracket with the reluctor ring. The screws fit through the locating dowels and hold the bracket to the timing cover, but are not responsible for the true alignment. In the photo below you can see that one locating dowel is in position, the other is missing:



Here's a close-up of one of the two locating pins:



It is easy to drop one or both locating pins while changing brackets, which can lead to misalignment of the bracket when reinstalled. Also, if the bracket is not parallel with the timing cover when installed, it can bind on one or both locating pins and not draw tight to the timing cover at one end. I will be very curious to learn whether both of your pins are still present.

For more information and photos, see the post at this link, which also shows Andy Stodart's timing advance bracket that you have on order. The photos are of our '93 VDP:

https://www.jaguarforums.com/forum/x...9/#post1138153

Cheers,

Don