Ok,

as I have tackled the light problem earlier and few other minor things this happens....

Problem itself is clear, as I turn the ignition on there are no warning lights or any gauges waking up. Turn it to start and still more of nothing. Good thing is that the first position works and I can play the radio and open and close windows etc. atleast I can use music to cover my swearing (and I do swear like a pirate right now)

Few things I have checked already, the ignition relay (I do have a feeling it does not get the actuating current as the multimeter says only 2.something volts on the side pin and 11.55 volts on the lowest pin)

I tried to hotwire the car (just to figure out if it is a ignition lock problem, metered it and no anomalities there as far as I can tell. Cleaned the contacts and put it back together... I really do not want to do that again!) as you already guessed, nothing.

One thing I have supected is the old (not in use) alarm that had a immobilizer unit in it, I have taken that out and restored the ignition relay wire that was used in it. My own idea is that there is some wire that I have not figured out yet that was used in the immobilizer that causes the problem.

Few pics of the alarm and how it was installed

 

Hi Kay.... you seem to be having a run of bad luck there.

Sorry can't offer any suggestions.... my immediate thoughts were the relay or immobilizer as well but you have checked those already.

I have had similar on the odd occasion, and each time I have assumed it has been the relay and just swapped them round.
Strangely if I left it for an hour or so and then went back it would all be functioning well again and the car would start fine.

Hope someone else can offer some assistance.
good luck

 

Hi Kay,

Very sorry to hear about this new problem! Can you tell us if the car was starting properly after you worked on the lights, or has this problem possibly arisen as a result of something done while you were tracking down the lighting issue?

I'm not positive whether your symptoms are consistent with a Park-Neutral switch problem, but it might be worth wiggling the gear shift lever to ensure it is fully seated in the Park position, and if the car still won't light up and crank, try starting it with the gear selector in Neutral.

Gotta run, but I'll try to think of other ideas and I'm sure you'll get better input from others.

Cheers,

Don

 

I Don't have bad luck, I just happen to have a jaguar that is just as whimsical and bad tempered as is it's owner...

of the linear switch at the gear selector, the symptoms are different and I actually tried that already.

Just prior to the most recent trick I did wash Tue car `(and got a ton of water in, and cleared that blogage) and after clearing that I tried to start the car and nothing. I do not believe it was the opening up of that draining pipe anyhow.

 

Kay,

What are the chances you accidentally tripped the inertia switch? Trip it and reset it just in case.

 

Did that too..

 

Hi Kay,

The sequence of events certainly suggests that your current no-start may be due to water ingress. Have you checked all your fuses to be certain none have been blown due to a water short? Another common problem on XJ40s is water in the CPU or the CPU connectors. Below are photos showing where the CPU is on our '93. Your '91 may be a little different, but the basic components should be similar. I'm including a photo-tutorial on removing the passenger-side knee bolster for the sake of future readers of this thread - I know you're familiar with the knee bolster removal by now!

Cheers,

Don

Welcome to Jag-lovers - Members Photo Viewing Page
Welcome to Jag-lovers - Members Photo Viewing Page

 

the middle fuse box is powered by a relay. this relay is earthed by the ignition key. So you have four pins. Two bigger wires, one of which should read 12v at all times. And two smaller ones, one of which should read 12v at all times. This relay powers centre fuse box, which in turn powers all stuff like your dash, ECU, TCU (if you have that).

I would shortcut the relay to see if that helps. Just connect the two bigger wires.

this basically powers everything that should be powered after ignitino. Left and right side fusebox are permanently powered.

 

Thank you Wilfred , I bypassed the relay today and voila I got dash light up and engine cranked.

looks like I need to look at the last 3 wires that I have not recognize that were connected to the alarm system I am taking off

 

You're welcome. Do you have White/Blue wires left? These earth the relay (through the ignition).
If these are intact, check if 1 of the smaller wires (the brown one) permanently has 12v. This should be the case.

The fault can only be in one of these two wires, now that you found out that bypassing the relay solves your problem.

Let us know what you find.

 

Well as update, trying to get the connections to original I got the kitten to crank... did not run yet though, I got "fuse2" code to the VCM though but ran out of time to check it out.

Looks like this has been solved, well atleast to the originating point of this problem now I just need to figure out why don't it start. Back to under the dash again tomorrow I guess

Kay

 

stopped by the jag to have a quick look at the fuses on my way to work, changed the one blown fuse and drove to work in my Kitten ... I am all smiles now!

problem solved, it was the aftermarket alarm.

Thank you all that contributed and helped me to solve this problem


Kay

 

Congratulations, Kay, and well done, Wilfred88!

Cheers,

Don

 

Good job Kay!!!

Was this related to the dash light display problem, or did the new (replacment) LLM fix that?

 

great news Kay
glad she is all up and going again for you
it can be so frustrating when something you know runs will suddenly not run for no apparent reason.
finding that reason in the maze of logic computers, wires, solenoids and relays is a task in itself.
I am so happy the guys on here were able to help.... they really are fantastic and know their Jags inside out

well done everyone

 

Rob,

Lights are still waiting for the new LLM, (should arrive this week) but unfortunately that problem did not get solved along this.