Yes, earlier vehicles had a different system.
Interestingly, though, the ECM splits one side of the trigger with 2,3,5 and 8 going to one pin and 1,4,6 and 7 to another.
I suspect this is to keep ECM coding the same as the older models which had a 2 wire coil and two ignition modules triggered by the ECM.
2000 MY ignition



1997 MY ignition




but you're not getting misfire codes.

 

I'm sure the 2 3 5 8 sequence isn't random and must have some significance, but what?

 

As said, it may be that within the ECU (i.e. on the circuit board), there is a sharing of components with the same grouping as the AJ26 ECU Ignition setup.

So if the injector swap and cabling check doesn't yield anything, then swapping the ECU would be the next option (at least that is what I would do).

It shouldn't be hard to find a cheap one, then all you need is to program it with the VCM/IDS.

 

What is exactly involved with this VCM/ IDS reprogramming

 

Which one of these connector blocks is the injectors?

 

Imho its time to bring it to someone that knows how to deal with this. The time it will cost to buy the ids/vcm and learn you how to deal with it, will be out of proportion compared to someone that can help you that knows how to do it. The cabling is all described in the electrical diagrams.

 

@Steve ....

RC helicopters and Arduino ...

 

Good point (an Arduino based quadcopter tried to kill me, leaving me with a considerable distrust of small microprocessors)

Avos is probably right but it costs nothing but time to clean the connectors and make the resistance checks outlined here and in JTIS.
If it gets to ECM swapping then maybe expert help is needed.
It certainly wouldn't be economical to buy IDS just for this.

 

I will still check the resistances. All the earths and connectors have been checked except for the earth that they show at the front RHS of the engine compartment which I cannot find despite removing the air cleaner box.

I notice that there are several companies who will check your original ECU and repair it as necessary. I presume then that IDS would be unnecessary.

Has anyone out there had their ECU repaired and can recommend any particular company

 

I can send my ECU to be tested for about £50 is this a worthwhile option. I presume that if they find no faults with the unit then it has to be something on the car itself. How reliable is this testing?

 

Have you contacted the company with your problem to see if they can check for it being ECM based ?
Have you had chance to compare ECM and battery volts at the OBD port to check for bad ECM ground ?

 

I did contact to see if they could test that particular Jag ECM but didn't specifically ask if they could test if the fault was ECM based, so I will do that.

Haven't checked volts at OBD port yet but will do that before I decide whether to send the ECM for testing.

Should the casing of the ECM itself be earthed. It's not bolted down or anything so presume it must get its earth via one of the plugs. Would it do any harm to run an earth wire from one of the ECM case screws down to a chassis earth?

 

Best leave it as is.
Multiple earth loops are a bad idea (current flowing everywhere, not as intended by the designe)r

 

Well I don't want to speak too soon but I think my restricted performance days may finally be over.
Over the past weeks I have just been clearing down the injector faults with my Bluetooth reader which clears the RP for one cycle, although I have still been getting intermittent NO TRAC and ABS faults, which came and went for no reason.
I finally checked the resistance across all the injectors and they all read the same which rather proved that there couldn't be anything wrong with them. So it really had to be the wiring or the ECU itself. As the 2,3,5, and 8 faults were on different sides of the engine it was unlikely to be the wiring that had suddenly just gone wrong especially as the car had not even moved for 2weeks when the fault occurred.
I was fortunate to find a garage who had a matching secondhand ECU to try and hey presto the injector faults disappeared immediately and have not come back after 30 or more cycles along with the NO TRAC and ABS warnings.
So it would appear that this fault was caused by a faulty ECU all along which was possibly triggered by the low voltage problems that happened when the faults first materialised.
It's easy now to say that I should have replaced the ECU much sooner but finding the faulty O2 sensor rather pushed me in the wrong direction and of course the ECU is not necessarily a cheap item unless you can find a matching secondhand unit.
So watch out Reliant Robins I'm coming to get you, and once again thanks to all who helped me with this problem and also praise to the 4000 plus people who have read and shared this experience with me. icon_imnotworthy: