Hello folks! Long story short, I'm an apprentice at a museum that also does repairs on mostly jaguars. We got this 1995 Jaguar XJR (1996 written on ecu, previous replacement??) with a no crank issue, which lead to us discovering this very nicely browned ECM with a matching lovely green plug on it! (Water damage..)
(They're giving it to me if i can get it running!!!!!)






4.0 Supercharged ECM's seem to be incredibly hard to come by and also expensive. The pins on the black plug are so corroded that at least two of them are severely damaged. While ive found out that you can buy the plug seperately I'm afraid some chips have been damaged by the water.

Does anyone have good experience with the inner workings of these ECM's?
I can find 4.0 and 3.2 n/a ecus much easier and cheaper so i was wondering if there are any physical differences between them? I assume there may be some form of boost controller added to the supercharged ECM? Could it be so easy as to just swap some chips over? If I were to find a 4.0 supercharged ecu I'm not sure if it would need to be reprogrammed or not.


Any insights would be very appreciated!

 

The male and female sides of the connector are readily avail as TE Connectivity Econoseal series 3 something

Vee has done the connectors / whole engine loom rebuilding

XJREngineer ( Andy on the original Jaguar AJ16 design team ) has gone inside the ECU to do tinkering with the maps and such

Re has 2 SC X300s to draw maps from if not already done I'm sure

The ECU hardware is the same between both inline 6 engines and Andy would have the details

The normally aspirated is the same as the supercharged with a couple changes

Pics coming

 

Thanks for the information! Sourcing those econoseal connectors is definitely my step 1 in this whole process.

If the ecm boards are the same, i should be able to buy a cheaper unit from an n/a 4.0 or maybe even a 3.2 and just swap some chips over?

 

Or maybe if theyre all identical i can just program 4.0 s/c software into the chips of the other versions?

 

From my understanding just the chips , Andy would have the practice

There is A TSB that may not apply to England or Sweden ( Great Britton build / pollutions regulations ) that has some #s in it

The TSB deals with an ungraded EGR valve you may not have

coming

05.1-26 amend4 (R493)

 

Now that I think of it, this car is a german import. I don't think that will matter much though. I've done some soldering practice on a couple of old walkmans so I can feel a little more comfortable tackling the ECM connectors. If everything goes well nothing was damaged beyond the connectors and it will start working once I solder on some new ones. If that doesn't work it's gonna get a lot more tricky..

 

Liquid solder will wick to the conductors better and leave your gaps between

Videos on youtube

The corrosion may have migrated up and into the wires strands in the wiring

When you put it all together there is an external to the ECU ground strap

 

Hello everyone! A little update on my XJR

I managed to source an ECM from a 4.0 n/a car (he wanted £50 for it!!!) and swapped EPROMs between it and my 4.0 SC unit. Miraculously, the car started!
It ran a little rough at first but then the computer seemed to correct itself and it ran quite good after a little while. I have no idea if the performance has been altered or if anything is wrong but I'm not getting any fault codes and on the first test drive it ran damn good!

I also replaced one pin in the car harness that had corroded off and cleaned the others.
Total cost for this otherwise FREE jaguar XJR: about 100 quid!!

I must be the only one that has tried to swap ECMs between a SC and N/A car.

 

The operating table: a supercharged brain in a better condition n/a body.

 

Now on to where the water leaks from,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, ,,,,,,,,,,

You will see a sheet metal seam as the front wheel quarter panel disappears under the plastic trough that the wiper post poke through , bath tube seal

the trough screws are plastic ( no rust ) so break off / strip easily , spray with penetrating oil a few days in advance

there are 3 other leak origine suspects

 

Or the water may have come from a hole in the bulkhead under the windscreen. Take the wiper arm off and remove the plastic cover, and at the very least give a good clean under there !

 

Ah yes there is a large amount of rust around the windshield. I should've specified that. I haven't properly looked into it and frankly I'd rather not! But it will no doubt have to be sorted unless i want a repeat of this procedure..