Hey everyone, just a quick question.

Removed the distributor to clean the area around it, and lo and behold I forgot to mark the orientation of the gear. Is there a way to set the timing/gear again? Does the ECU do it automatically'?

 

Someone will correct me soon enough, but I am going to say that it doesnt matter, the computer controls it.

 

Hi it's important place distributor gear with PMH after you can turn it with no problem.

 

Hi jaguarguy13,

If I recall correctly, the distributor must be installed in the correct orientation with cylinder 1 at Top Dead Center on the compression stroke and the engine timing marks aligned. I believe the procedure is given in the manual at the link below:

Haynes Jaguar XJ40 Repair Manual

The computer can accommodate some tolerance in distributor rotation, but if the distributor is turned too far, or installed with the crankshaft in the incorrect position, the firing order of the cylinders will be incorrect.

Cheers,

Don

 

I am wondering if my spark jump problem might be due to not having the distributor in the exact correct alignment.
Is there some fairly complete documented procedure for setting the distributor orientation?
I figure the engine has to be set to TDC but I don't actually know if there are any external pointers or marks to tell when the motor is at TDC.
Then once I have it set to TDC, is there a specific mark inside the distributor that number one plug wire should be pointing to?

Any info would be appreciated.

 

ignition is controlled electronically so i think distributor is in fixed position and no alignment possible, think only as i don't have manual anymore.

 

No, the distributor is not fixed. It can be rotated.

 

This Haynes manual is complete **** when it comes to correctly aligning the distributor.
Overall this manual is near useless.

 

Answered at the other forum.

https://forums.jag-lovers.com/t/corr...ation/432937/5

 

Hi Steve,

The Haynes manual clearly states that the distributor and block must be marked prior to distributor removal, so in that regard it seems unfair to criticize the manual for trying to save you from the predicament you are now in. But we've all been there and feel your pain.

The ECM does control ignition timing, so the exact positioning of the distributor is not critical. But the distributor/rotor/cap orientation must be close enough to the theoretically correct position so the ECM triggers the cylinder 1 spark plug when the cylinder 1 piston is close to TDC on the compression stroke. If the distributor is rotated too far from the theoretical correct position, then the cylinder 4 or 5 spark plug could fire instead, causing a no-start condition (cylinders 4 and 5 precede and follow cylinder 1 in the firing order).


Here is the Distributor Renewal procedure from the Jaguar Factory Workshop Manual:






Here is the description of the ignition timing from the FWM:




Here is a diagram from Haynes that gives a rough orientation of the distributor and the firing order:




Here is the description of the distributor and ignition module from the Engine Management System manual:



Regarding your spark jumping issue, my first question is whether you have checked and cleaned both ends of the engine ground strap? That is the ground path for spark, so high resistance due to corrosion at either end of the engine ground strap could prompt the high voltage to find an easier path.

I can't remember the symptoms this was supposed to address, but at some point Jaguar changed the orientation of the ignition module to the coil by 90 degrees (I think). Bob will remember this and what it was supposed to solve.

What is the condition of the wiring at the coil? On our '93, the insulation on the wires hardened and cracked off.

Cheers,

Don