No start issue V12

Sbobev, thanks for posting up that wiring diagram, that will help us a lot as we did not have that info.

You may want to download the copy of the electrical diagrams for 1990. The picture I attached is for my 1995 and the pinout could be different (functions will be the same or nearly the same - I have electronic outbox which also receives signal from the Marelli ECU - that might be the most significant difference)

Ok Steve, thanks. Where can I find the 1990 diagram? I have the CD but it’s such a pain to search around on it. I never know which vintage engine I’m on.

MY 1990-91 electrical diagram in PDF. I hope this helps you solve the annoying no-start problem:

Electrical.pdf (3.2 MB)

Steve, that is outstanding!! Thank you very much!

Paul, we do have a stethoscope and will check the injectors. Thanks.

Robin, thanks for that info about the direct acting cams. Did not know that.

Guys, since the only ignition related component we didn’t replace is the ignition amps on top of the core support, should we go after them? I don’t have an understanding of what they do or if they susceptible to failure. Thoughts??

I think you’re on the wrong track to solve your no start problem. Mindless part swapping is a big NO on the Jaguar V12. It will empty your pocket in very short order and will unlikely produce the results you expected.

Have you priced a new Marelli amplifier?

Please take this as a useful suggestion/reminder, not as a troll-like comment. DO use of the magnifying glass in the upper right corner of the screen. This is the search button.

This thread on the topic of Marelli amplifier was active just last week:

To sum up - the Marelli V12 is essentially two I-6s with a common crankshaft. Operates as such. The engine will start and idle on one bank only.

If your coils are connected correctly (you indicate there is fuel and spark in post #1), I can’t think of another reason (besides my concerns about the replacement harness) the engine won’t start.