Hello All, I picked up a Damlier Double six in Oregon a few weeks ago with 58k miles. It is a pretty rare car around these parts and was imported at some point but I don't know yet from where.. It is also a LHD car. The car had sat for a while and I didn't have too much trouble getting it running. I then made the mistake of degreasing the engine compartment and now the car is dead, dead, dead! I have spark and fuel pressure. What I don't have is injectors firing. I have gone through everything, all the relays, all the grounds. I did multiple jumpers on the main and the fuel pump relays to bypass things that might not be working. I swapped out multiple ECU's to no avail. I even have a Lucas Epitest unit that I have never had to break out before, but in this case I decided to see if it was useful and it is not so much so far. Plugging it in to the ECU pigtail, the first test is, is there power to the ECU. The Epitest has no reading, but I do have power to the pin on the pigtail that the manual says to check, so maybe the unit is not functioning. I am also running into problems with what is in XJ manuals and the Epitest manual and where things are at on this car. The ECU pigtail in the car, does not have some pins that are showing as should be present in the epitest manual. What I believe are the main and fuel pump relays are not where they are supposed to be according to the shop manuals. I have checked an cleaned every plug, every ground and ensured every single critical wire was properly hooked up. I checked and cleaned all the fuses in all the fuse boxes, checked and swapped out every relay under the dash and under the hood. Nothing. It just cranks over. I can fire it if I spray ether into the intakes, but that is about it. I have good pressure in the fuel rail, so it boils down to the ECU and the fuel injectors. I also checked and cycled the fuel cutoff switch, things like that. Any ideas you may have that I am not thinking about would be greatly appreciated. Thanks.

 

Are the injectors clicking? If not, and I presume not, check the "dreaded white wire" coming off the ignition amplifier. It quite delicate and could easily be broken.

Cheers
DD

 

As Doug said, the white wire exiting the Lucas box into the loom is a lilely cause. It is shielded insiode a woven steel mesh, which MUST NOT TOUCH the inner wire or be earthed to it. If it is not properly connecting to the ECU the injectors cannot fire. Checking it for continuity to the ECU is the first thing to check. Attached is an ECU pinout diagram (courtesy Grant Francis). Pin 18 receives the signal.
Also check and clean the connector to the resistor pack. If this is not connecting properly the injectors will not fire either. See here:
https://www.jaguarforums.com/forum/x...sistor-134745/
There is also a twin wire that comes up to the Lucas box from the base of the distributor. If this is not properly connected the car will not start.

 

I agree with Doug.

It WAS running, you gave it a bath, now its NOT running, so the issue is under the bonnet, simple.

Not sure where it is on the Sedan, probably the same place, the EFI resistor Pack, mounted on the inner guard, near the radiator, RH side, on the XJS. The plug goes in from the bottom, and is well known to crud up and STOP Injector pulse. Remove that plug, clean it, and the socket, clean it AGAIN, and replug. That sorts 90% of that issue.

That dreaded wire is equal to #1 on my list. It goes to Pin #18 of the ECU, so continuity is easy to test, and then Ohms to earth, should be Zero.

MY opinion, diving around all over the car will solve little, and I dont trust the manuals etc, never have, but we Aussies are a different bread.

 

The white wire was probably the first thing I checked and it is good, as well as the wires coming out of the dizzy to the ignition amplifier. I tore apart and cleaned the resistor pack, it looked good inside, but, looks can be deceiving. I have another one floating around here somewhere and should swap that out as a test. I am also starting to think that cleaning the engine compartment was not the cause, just a coincident as to the car deciding not to run. after cleaning the engine, the car would start and run, but not very good because I had water in the distributor. I got that dried out and it wouldn't start soon after that. I will continue to double check a few more things. I appreciate the diagram that was sent. Thanks.

 

To be 100% sure what is going on, pull one of the front two injectors, point it in a jamjar, and see if it is spraying at all while a helper activates the starter. Also worth using a noid light on the injector plugs to see if any of them are getting power.
Have you separated the plug between the injector loom and the car loom and cleaned it?
It would also be worth trying another amplifier, or at least checking on cranking that the white wire is getting a signal.

 

Something else now you have cleared the mud a tad.

When you sorted inside the dizzy, you had the cap off, check. Lift that cap again, and look at the centre post, for the spring loaded carbon brush/contact thing. They fall out, and go unseen. The car can? start without it, but rare, and crappy, as the coil energy will jump that gap. Been there.

Next:
Ign ON, QUIET PLEASE, open the throttle real quick, and LISTEN. You should hear the Injectors "Click".once as a batch. NO click, you got connection issues in that circuit.

Spark, easy, Get any OLD spark plug, attach any easy lead, and lay it on the head dome nut, and crank. You are looking for a Fat Blue Cracker, anything less will not start that beast. DO NOT do that test with ANY spark plug removed from the head, as engine fires are a nasty thing.

 

A few things: 1) you mention the fuel pump relay and the “main” relay beside it. They sit in the radiator support panel toward the right. The main relay controls the fuel pump relay….but you say they are not in the correct position? Have you tried swapping the relays on their (red and black) bases? The relays are identical except that one has an 87A connection as well as an 87, the other has only the 87.

2) Have you replaced the module in the ignition amplifier? This is a primary cause of non-start in the V12. Easy to replace but use ONLY the GM Delco 1906 relay, NOT an aftermarket version.

3) there is a delicious, pinkish wire from the distributor under the cruise control bellow. Rodents love the taste of the wire’s coating and this too is a non-start cause.

4) Very rarely, on the V12 the distributor pick-up can be faulty.

On a various V12 cars I have experienced all of the situations mentioned (meaning one of them on individual cars not all of them on one car!)