Hi all,

I went to start my XJS today after around 3 years since the last start. I've been recommissioning it recently.
On turning the ignition to start I get absolutely no response from the car - no clicks, no dimming of lights, nothing.
The battery is definitely ok.
It's like something between the switch in the key & the starter motor just isn't working at all - like there is an immobiliser.

Does anyone have any ideas? It worked perfectly 3 years ago & has been stored in the dry.

 

the park/ neutral safety switch would do this. Try starting in neutral?

 

Have you got control/warning lights on???? As Xjeffs mentioned - check if your auto gearbox on Parked/Neutral Got myslelf on this after replacing few relays and radio (moved selector to 2 position)... Simple things first. Then I would check the plug to your starter motor solenoid. Immobiliser will cut the ignition, not starter motor. Check fuses if not covered in white residue...

 

There are lots of warning lights on the dash with the ignition in the on position, but to be honest I can't remember how may were on/disappeared once started when I parked it up. Are there any systems that can prevent it starting?
While it was off the road I replaced the front calipers - I'm yet to bleed the brakes through completely. Wondering if it could be related to that somehow.

Just to clarify, you're supposed to start in Neutral?

 

Ok, tried starting in park/neutral - no joy, & the warning lights mostly all go out - Battery & oil light are on.
The connections on the starter relay look ok, & I removed the metal 'can' to take a look at the internals - all looks ok.

Worth mentioning my car is a 1989 & has a Hella branded starter relay, & different wire colours to all the troubleshooting guides I can find online:
The larger wires are Blue/Red, Blue, Blue/white
The smaller are Brown, blue/black, & there is a red thing that looks like a capacitor bridging these 2 terminals in the wire loom.

 

Not required to start in neutral but one of your 2 options. If your safety switch is out if adjustment, sometimes you'll find that it will crank in neutral or somewhere close to neutral, but not in Park.

 

Turns out i'm an idiot - the relay I thought was for the starter is for the high/low beam...
Does anyone know where the starter relay is located in a 1989 RHD UK car?

 

If you cannot hear any tiny click during the key turning (f.eg. relay) - that's possibly gearstick's position switch. Can be stuck over time...

 

Hi Asdrewq

The chances are that you have disturbed the 'Fuseable Link' in the Boot/Trunk when recommissioning your Car, which is on the Battery Positive Lead and it doesn't take much to do this as the smallest of movements will do, where this will give you a very mysterious 'No Crank' situation that could take for ever to track down

So have a look at this Photo and Push those connections together and even jiggle the leads around if you have to as this is highly likely to be the cause of the problem

Also always Start the Car in 'Park' as while you can start her up in Neutral the Transmission won't be locked so not a very good habit to get into, as when you Park the Car up, its more Normal to leave her in 'Park' as an extra Brake Safety

 

I don't think RHD vs LHD drive makes a difference. Not sure. On a LHD car the starter relay is on the RH side of the engine bay near the hood latch.

In any case you're looking for a relay with brown, white/yellow, white/black, and white/red wires.

Cleaning connections at the relay, battery, and main ground can't hurt. You might get lucky and fix the problem.

If you have a test meter or 12 test light we can walk you thru some specific checks

Cheers
DD

 

My suggestion.

Get access to the back of the Ignition Switch.

You will see a short loom, with White/? wires.

Probe the White/Yellow wire, turn the key to START, read the volts, you should see 12v ish, indicating that the actual Ignition Switch electriclal section is working fine, most are NOT.
This test is NOT reliant on gearlever position etc, it is the beginning of the whole process.
If that volt reading is zero, or lower than 10V, that electrical section needs to come off, and be opened and cleaned. This is getting very common now.

This attachment might help.

ALSO

From that starter relay is a White/Red wire, It works its way to the starter solenoid, BUT, just at the point where the Transmission dipstick is, there is a spade joiner in that wire. They are easily seperated, and also get quite grubby inside, and block the volts TO the starter, BUT, you should hear that relay CLICK even with this fault, and you mentioned NO clicking at all, so I doubt this wire, but, again, its simple and quick to check.

I have a PDF on cleaning that Ignition Switch, but it is in Cyber Space at the moment, I will go drink coffee and keep looking.

 

Thanks all - lots to check! One problem I have is I backed the car into a single garage so can't open the drivers door very far (& can't get to the passenger side at all)... the dash cowelling under the steering wheel is already off though so I can hopefully still access everything.

I did find the start relay - it was under a bit of black plastic near the brake reservoir.
Reading about last night I saw a recommendation to jump the brown permanent live wire to the thick white/red wire & see if the engine turns over - it did! so at least I think the starter is ok.

I have a multi-meter to check voltages.

 

I actually found two different '1989' wiring schemes for the relay.

BEFORE VIN 153560

Brown: 12v constant
White/yellow- 12v with key turned to start (trigger from ignition switch)
White/red-12v with key turned to start (output to starter)
White/black- ground (key must be 'on') with gearshift in "N" or "P"

VIN 153560 and later

Brown/slate- 12v constant
White/yellow- 12v with key turned to start (Trigger from ignition switch)
White/red- 12v with key turned to start (output to starter)
Black/green-ground with gearshift in "N" or "P"

You probably have two white/red wires. The larger gauge goes to the starter; smaller gauge to the EFI

If you have white/blue wires, ignore them.

Cheers
DD

 

Hi Doug, nice one, thanks. My vin is 163xxx, & here is a pic of the relay wiring:



I think this is right:
white/red thick - switched, to starter (tested - starter works when jumped to 12v)
White/red thin - switched, to ECU
white/blue - switched, to ???? (same relay terminal as white/red thin)
Brown - +12v permanent live
Black/green - coil ground, via gear selector switch
white/yellow - coil +12v, from ignition switch

I'm thinking I'll test for +12v / ground from the coil spade connectors, & work backwards from there for whichever side appears not to be working?

I've checked the fusible link in the boot & it looks to be ok.

 

Andrew
If you can identify the wire that comes from the ignition "start" position, where it joins the starter relay, you can trigger the starter by giving it 12vs. The wire in question comes from the inside via a connector as grant explained in an earlier post. If, for instance, you put a lead on the 12v positive terminal of the coil and then touch the other end to this wire, or to the terminal on the starter relay it is attached to, that WILL trigger the starter.
So if you place the gearstick in park, ignition on, and then touch the 12v wire to the relay/wire I am describing, if the starter etc are all good, the car will turn over on the starter motor, and may even start! Just release the wire connection when you want the starter to stop. If this does work, then you know for sure the problem is in the ignition switch/safety switch t circuit to he relay.

 

My quicky suggestion.

That White/Yellow at the relay, unplug it, test probe it, reach in the car and turn the switch to the start position, and note the readings.

Since access to the Interior it tight, due to the parking position you are in, that wire is basically the other end of the Ignition Switch wire I mentioned above,

If you have 12V etc at that wiregod, replug it, then I would fit a separate earth wire to the earth terminal of the relay, and try it, thus by-passing the Gearlever switch etc.
This will eliminate the relay, MAYBE, and point to the Gearlever area as the issue.

Make sure the thing is park, or it could run away on you, HA>

 

So I tried probing the relay coil wires.
The white/yellow showed no response when the ignition key was turned. Result I thought! there's the issue.
Then I tested the ground on the green/black wire while moving the gear selector about - No ground there...

So it appears both the gears selector ground switch AND the +12v ignition switch have both broken while the car has been sitting. Either that, or i've broken the wires somewhere in the loom - I did have to move those 3 large loom sections that sit on the cross brace about when I removed the inlet manifold so am slightly worried about that...

A bit deflated by this, I decided to just manually hook the relay coil up with a small battery & some spade connectors, leaving all other relay connections in place, to see if the engine would start - IT DID! & ran very nicely - far better than I remember. No hunting, & actually sounded like it was running on all 12! super smooth with the revs raised to 1500 or so.

So at least I can now move it.

I'm not sure this is a long-term starting solution...:

 

Goodo.

That is an AWESOME Anti theft device, well done.

I reckon that loom is where you will find it, and aligns with the saying of mine, ALWAYS trace back to where you have been messing around, and 99% of the time, sorted.

Keep us posted.

 

Given that it hasn't moved in 3 years, wouldn't the first suspect be that you may have suffered from a hungry rodent? They do like wiring.

 

I finally fixed this!

Turns out my car.... has an aftermarket immobiliser! I had no idea, have never used it, have no idea how it was supposed to be controlled - there are no switches or fobs, the car always just worked.
Well until I left it for a while, then the immobiliser decided to start immobilising again.
I found it wired in behind the ignition, stripped it all out, re-soldered the white/yellow wire back up (this was intercepted) & it started from the key.

I have also realised my car originally had the Jaguar CATS aftermarket security system, but the control box in the engine bay (Near ABS pump) is long gone, & the loom/straight connector is just left there dangling, with some of the wires having been cut/tampered with in the past. Wondering if this is why my power locks don't work - the fuse instantly blows when the solenoids are supposed to 'unlock'...

Anyway, i'm glad it's fixed & no stripping of the engine bay loom is needed!