You can get 2 new ECU connectors and you will be 100 % . Ebay has some harnesses and I would recommend splicing at the original factory splices up over the engine fuel rail as mine were fine but other owner's cars are not . I have the whole engine management wiring harness colored in and makes it easier to follow the wires as I did my whole harness .

 

Is it 35 or 36 as the Jaguar wiring guide shows 35 ( Green / Black wire ) as fuel inhibit and 36 ( Blue / Brown wire ) shows A/C inhibit to disengage the A/C clutch . 35 is a digital signal so it would be hard to trick . 36 is a discrete ground . Keep in mind the ECU connector map I made showing both the red and black connectors is the connector side if you had them in your hand . The ECU view is opposite and on page 23 of the wiring guide . The wiring guide reference can be found on page 55 on the left side in the earlier supplied pdf . A recommendation on pin cutting would be to desoldier the pin on the other side of the board and lift the pin enough to lose contact and not have to cut the pin . As you can see it would be easy to replace the connector .

Editing

 

I have ordered a pair of 36-way ECU connectors and the 36-pin housing and will have to find local help with removing and re-soldiering them with the special touch you suggested. This area is entirely beyond my DIY capability....

 

Maybe since the SLCM is different for different parts of the world it may be the key unit with the immobilizer feature option that sends out a digital signal ( according to the Jaguar wiring guide ) on the Green / Black 35 wire to enable . Just a guess , the not immobilizer feature option has a constant enable signal or no signal at all .

Although the ECU is also different for different parts of the world it may only handle the differences in engine regulation to get the required emissions result .

What I mentioned on the valve cover is a secret as the engineering is done , just the practice needs refining .

 

Update: the harness side connector arrived, all problem coppers replaced, hooked Rose up with a good ECU from another XJR but she stays sleeping. Mechanic managed to force starter to turn by direct wire but there was no spark, as before. Ignition system has power supply but no signal. Fiddled with Pin 35 but nothing changed. IDS showed ECU working, was able to scan codes and clear some codes reducing to three, two relating to the EGR (disabled from Rose), and "P1621 - ECU engine immobilization input circuit malfunction". Mechanic has given up advising that we must first tackle the immobilizer first or else it would be an endless investigation with no prospect of recovering Rose. Andy said he would revert in about a week.

 

By power on the ignition system do you mean constant power at the coils and no ECU provided grounds ? Have you looked at the condition of the Papa Indy 1 connector as you can do this yourself without pestering the mechanic .

A hard reset may unlock a immobilization command signal in the SLCU .

Do you have RPM on the instrument cluster as you rotate during starting as the cam ( then later ) crankshaft sensor may have failed even though you show no codes .

 

Yes.

Yes.

Don't know if this works or not. Battery disconnected many times and tried clearing the immobilizer signal with IDS but unsuccessful.

Starter turned but engine does not crank at all. Rose has a new Crankshaft Sensor. Saw the crank angle sensor rotating though. Somewhere somehow the car has been in "locked" situation, unlikely caused by a hardware failure but software issue. Sill have the corroded ECU that was designed to bypass the immobilizer, but several pins inside the Red and Black connectors have fallen off, and replacements are still in the mail. The long Chinese New Year holidays here means nothing can be done until the parts arrive and I can find a local specialist to remove the corroded and solider on the new 36-pin connector and reconfirm with Andy which particular pin or pins to fiddle with to recover the ill-fated ECU.

Heard from a local Jaguar workshop that at least three X300s here were given up and salvaged in the past due to failure to tackle the immobilizer. Have asked Andy for another special ECU (as spare or the final solution) while I try to revive the corroded ECU.

 

The fact that the starter doesn't rotate normally is important in that that aspect my be immobilized as well including the ignition ECU timing control grounds beyond what the Jaguar wiring guide pin Red 35 has labeled as fueling inhibit ( not used NAS ( North American ))

Thinking outside the ECU inhibit to the other aspects of the car not starting is the reason for covering the bases of starter rotation , ignition control , and fuel pump / injector control as it could be one of those that just happened to fail at the moment . Do you have fuel pump turn on other then it's injector control ?

But you have swapped different ECU's around with successful start - up ?

By Saw the crank angle sensor rotating though can you elaberate ?

The ECU side connector would be relatively easy and not too complicated to replace and restore vs. something more complicated and hard to find a technician to perform , but I would suggest the heat gun method as a more elegant process . Luckily a part source was found for both halves of the connector(s) to restore that aspect to 100 %

By hard reset it is beyond the removal of the positive cable but is the bringing the positive and negative cables both together as it resets the out of of sequence multiple ECU's back to zero state and you can do yourself very easily , or at least a different mechanic shop without pestering your master mechanic that is guiding you .

Dude , I like the color of your car as I was thinking a medium candy burgundy wine after repaint with the same window chrome and hood ornament but with add mirror and lower grill chrome so that she'll be the prettiest Jaguar on the whole block.

 

Let me clarify. When the mechanic directly wired to the starter to turn, the engine cranked (hence noticing the crank angle sensor rotation) but engine did not fire up. Mechanic tested Cylinder 1 by inserting a spark plug touching valve cover but found no spark. With the key at the ignition-on position, all relays and fuses tested OK but ignition and starter has no ground or signal. We can hear the fuel pump working when key is at ignition-on position.

The mechanic and I discussed whether a hard re-set could be a way out, and his advice, with which I agreed, we might be under-estimating the wisdom of Jaguar's factory security features.

For further clarification, Rose has been tested with three ECUs. Andy wrote me ECU1 to cater for Rose's auto-to-manual conversion, but before ECU1 was fitted on Rose she died. At that time we did not know that ECU was the culprit so Andy wrote me ECU2 to bypass the immobilizer in addition to what ECU1 could do. Rose was reborn with ECU2, and had been in good health until lately when she had no hot-start. In diagnosing the cause of the no-hot-start, Rose died. In fact, before she died completely she almost came back when we tried starting with the MAF unplugged; we also confirmed that there was spark when we tried forced starting. She then died completely when we made further attempts and tests. She was motionless when turning the key. We then found ECU2 corroded on the red and black 36-pin housings; we also found several pins missing after we tried to blow away the oxidation. Then we removed ECU2 and tried ECU1 on Rose but she refused to start. We then put ECU1 to another XJR and that XJR started right up. When we tried the ECU on that XJR (let us call it ECU3) on Rose, which we confirmed to be in good working order, Rose did not start. As ECU1 and ECU3 both are NOT equipped to tackle the immobilizer, and both were also to communicate with the IDS, but were unable to start Rose, we believe that Rose's no-start was more than a hardware issues.

Whatever, the time has come to a natural break as all shops and help would be unavailable as today is the eve of the Chinese New Year, and apart from the public holidays, most workshops and electronic repair services would be closed for seven or even up to two weeks. Poor Rose has been towed home. I now await Andy's advice to my emails and a full set of the ECU pin housing and connectors to arrive and start from there.

 

On and off there were some discussions on colour choices for the X300. I started one entitled "Favourite colours for your XJR" sometime ago and let us go there if folks wish to revive the topic, as the original paint can hardly withstand mother nature and we now have more choices such as car wrap....

 

Maybe with the film wrap M'Lady P can have her dream come true

 

Cute Pink Lady, and she is manual!

 

No , that's just a joke . But I would like to convert it over to manual someday after I rengineer the engine to what it could be without a supercharger . The limit would be the clutch pedal hardware as the factory standard Getrag 290 / NV3500 transmission is commonly available off other cars . But that's down the road .

https://www.jaguarforums.com/forum/x...to-xjr-153668/

https://www.jaguarforums.com/forum/x...-trans-139159/

 

Update: Have bought various parts to replace corroded ECU connectors and receptacles.




Have passed them to my mechanic to find a specialist who handles ECU electronics to remove the corroded parts and weld back new parts. Have also sought help from Andy for a custom-ECU that bypasses the immobilizer as a final solution.

Meanwhile also found a used Rochester Valve and Purge Valve to tackle any possible airlock issue in the fuel system that might be causing difficulty in hot-start.




Hope these will bring Rose back.

 

Andy's special ECU arrived at my door in the afternoon; hooked up and ............ .................Rose started on first crank! Tried a few times and Rose responded normal. So indeed the immobilizer has been playing up when the old ECU died. A new ECU that does not deal with the immobilizer failed to start Rose last time. I now notice that if I ignition on the car but do not crank the engine, the CEL light stays on after all other check lights (Transmission, Traction Control, ABS, Coolant Level, Airbag) go out. So if the CEL went away as before it meant the engine was immobilized.




Will have more to tackle before re-assembling everything. First thing first is to stop any moisture from finding ways to the footwell where ECU is located; waterproofing was inadequate last time. Rose must not die again for the same cause.

Will have to test thoroughly that Rose has no more hot-start issues.

 

https://www.jaguarclassicparts.com/u...-finisher-lowe

 

With reference to Post #1 and Post#40 above, my mechanic and I have finally located the source of water entering into the engine ECU. The metal on the firewall surrounding a rubber plug, presumably one removable to allow cables travelling to cabin or form the engine bay, has become badly rusted that rusted fragments simply fell off when removing the cover of the rubber plug. There is another one on the other side of the engine bay, but that one is normal, no rust.

This secret passage has damaged two ECUs now, so I am using a third one, thanks to Andy who has helped rewrite this one for me as it is custom-made for (1) conversion from auto-to-manual, (2) timing advance in place of the Andy Bracket, and (3) disabling the immobilizer.

This hole has now been sealed permanently for good. See pictures below:

 

One more area is the metal seam under the long plastic trough for the windshield wiper the metal seam between the engine firewall and the right fender can allow water in . I just sealed it with silicon sealer and done . The seam is at the highest point , 4 inches long going Fwd to Aft . You see it in your picture .

 

Yeh, should do that as you suggested as well. The mechanic found the underside of the dash pretty humid. It could be caused by air-con condensation, but it could also be rain water seeping underneath, however little would bound to cause problem sooner or later.

 

I found on mine the upper and lower half of the conditioned air main plenum in the very center of the dash had become unclipped from each half and spilling fog under the dash causing surface rust on items under there . Duct tape the 2 halves together . A more perminite repair would be to fish a couple of loops of wire around the plenum and pull 2 halves together by twisting the wires until you can reengage the halves snap clips into each other . They will want to unclip as it heats up in service so you would want to keep the wires on there .