Jaaag XJ6 NOW SOLD.

[richardthestag]

Range rover classic efi failed to proceed recently. Started and ran on lpg but no way on petrol. 0v to pump, eventually tracked down to one of two relays, special bugger relays as well!

 

One was the fuel pump relay and the other was an ignition injector relay. They both had metal covers, part number iirc was afu2913L and they were bosch.

 

Fitting a standard relay allowed the car to start and run but drained the battery overnight.

 

Bashing the original relay on the concrete got it running again

 

Only other thing that failed was the pump fuse doh.

 

The relay was incredibly tight so i used a screw driver to lever it out, must have bridged the 12v and earth. Minor glitch that was discovered when i was using a multimeter to check the various terminals on the relay holder.

 

If these two relays exist on an xj40 check the circuit, on RRC one relay provided a feed for the other. Signal for the pump relay came from the coil, iirc. I now have a oem spare, new off the shelf replacements worked but drain the battery. New old stock are worth weight in gold. Second hand acquired for £20. Should be able to get the circuit up and running using a paperclip if you know which relay is fubar and which terminals need 12v and are not because the relay is stuck.

[dome]

Scotoshite rescue mission anyone?

[Skizzer]

Ah I see Dave has beaten me to it. I was going to stick a post on before it met its maker to see if it was worth something to someone as, with regret, it's not worth more than scrap to me.

 

The facts are these - when it was running it was a lovely to be in and drive, if very scruffy on the outside, old barge. When the fuel pump packed in it was absolutely worth throwing £80 at a specific easy fixed fault. When it then didn't work (ignoring the now cracked fuel rail) it became one of a hundred things that you can only really rule out by replacing random parts and hoping you get the right one sooner rather than later. At the end of the day it's a £450 quid runaround that's seen better days and is by no means rare or mint and I don't have the time or money to save what is, realistically, just an old car.

 

If someone has one and needs an interior then it's got one. There are doubtless lots of other bits on it that work fine, and if it could be useful I'd rather that than it rust in a heap. Heaven knows someone with the mechanical knowledge and time, and a hefty wallet to sort the outside, could even fix it and make it lovely. Or you could just buy one already in that condition for half as much.

 

If you stand and literally pour petrol into the injector holes she'll start and run fine - until you stop pouring. The various xj40 forums were at a loss. When it seems so close to being a running barge again it pains me to admit defeat, but there comes a time when you need to know when to stop playing autoshite roulette and this is my time with this car.

 

I'm not holding anyone to ransom or trying to threaten a sale out of folk, I just thought I'd see if it might be useful to someone before I simply bin it. If nobody can use it that's fine, at least nobody will see it in the scrappies and moan they never got the chance to do x, y or z with it.

 

Fair enough, apologies for being grumpy yesterday, it had been a long and difficult day.  I feel your pain, and as I said to CortinaDave, thanks for giving someone brave/foolish the chance to take it on.

 

Still hoping for a rescue mission though!

[Magnificent Rustbucket]

It is awful when you have tried everything, yet the bloody thing still won't start.  Changing the fuel pump on a late XJ40 is a big and unpleasant job; after that to still have a car which doesn’t run it’s not surprising you’re jaded with the car.

 

 

I didn’t see your thread on the various Jaguar forums when you wrote them, so I’m not sure what you have done. My visits have been more sporadic of late.

 

I still think it is worth having one last try though, even if it is just going through the problems and symptoms one more time on here to see if there is anyone who has a brainwave. I’m not much of a mechanic, but here are a few thoughts anyway. Apologies if it is all a bit obvious!

 

I am presuming the fuel pump is running. Does the fuel pump make a priming burst “merrrh†sound for a second when you switch on the ignition?

 

It should do this – the fuel injection sends a second long burst of fuel to the engine when the ignition is switched on to build up fuel pressure for the engine start.

 

If it does not, then the fuel pump may not be running. There are several things which can cause this:

 

The plug to the fuel pump is burned. This large square black plug is located near to the battery. Sometimes a failing fuel pump can draw an excessive current and melt this plug. I doubt this will be a problem on you car, since you have replaced the fuel pump though!

 

There is a fuel pump relay (on the bulkhead on a 1994 car? - though i would have to check that, it changes with model year) which may be faulty.

 

The heated oxygen sensor also has a relay – yellow base on the left hand side of the bulkhead under the bonnet. If this is removed the fuel pump will not run. A faulty relay here will also disable the fuel pump.

 

How old is the fuel filter? – Could it be blocked?

 

The fuel pressure regulator (the barrel shaped thing on the fuel rail) can fail, causing fuel pressure to drop.

 

The coolant temperature sensor (the sensor is on the top of the thermostat housing at the front top left side of the engine, connecting to the top radiator hose – it is the black one with two electrodes) can fail. Generally, these cause excessive richness, with running problems and a fault code. Occasionally, they can report an overheated engine. If the ECU detects an bad enough overheated situation, it can inhibit the injectors.

 

If the ECU reads a WOT when the throttle is closed due to a fault on the throttle potentiometer (the red square plastic sensor under the throttle) then the fuel pulse will be shut off. The Jaguar XJ40 fuel injection computer turns off the injectors at WOT as a way of clearing a flooded engine. The Throttle potentiometer can be measured with a multimeter to rule it out. The plug is marked in this photo:

 

 

Back probe the TPS connector black/yellow common ground wire + green/yellow signal wire with the ignition on, but without the engine running should see a reading of 0.57v-0.62v with the throttle closed. The TPS should read about 4.8v at WOT. A little variation is acceptable since the ECU learns to accommodate wear, but it if is reading much different then there is a problem with the TPS. If it sees WOT, the injectors won’t fire.

 

Are the injectors getting the signal to fire? Do you have access to a noid light to check the firing pulses are taking place?

 

 

If the injectors are not firing, then you could have a fault with the ECU itself (though these seem very rare on the XJ40, it could have got wet if the car leaks).

 

Does the car have an aftermarket alarm? These seem to cause a fair few problems, but mainly on older cars. The 1994MY had a factory fitted alarm.

 

If you have a spark, then the Crank position sensor (the usual suspect on a non-starting XJ40) is OK. No spark and no fuel is most often a failed CPS.

 

If you are getting a good spark at the plugs, I am presuming they are dry of fuel? Lack of compression is very unlikely. They’re a tremendously strong old thing, the Jaguar six – and besides, you would have been having plenty of other symptoms long before a lack of compression ended the engine.

 

If the injectors are pulsing, the pump is running yet the engine still does not run, the only thing I can think of is that either you have not got enough fuel pressure (failed fuel pressure regulator or incorrectly fitted fuel pump canister housing in the fuel tank), or that all six injectors have failed at the same time. Unlikely though this sounds, a poster on Jag-lovers had all six injectors simultaneously block. He was at his wits end to find the problem and changed them all simply because he could not think of anything else left to do! – And it worked!

[CortinaDave]

The pump works. Its making noise and fuel is getting to the engine, but it doesnt start unless you pour fuel directly into the injector holes, it will then run for as long as you want to stand there and pour.

 

The old fuel pump wasnt making a noise and was stone dead, thats why it makes no sense that with the pump replaced and the new one clearly working it didnt run, as until the pump died it was absolutely fine. Suggests the pumps been fitted wrongly etc but who knows.

 

No more fault finding can take place because the mechanic cracked the fuel rail, and hes not spending any more on it replacing the fuel rail having already laid out for the new pump and fitting etc to still have a dead car.

 

I suspect its something simple given the above, but hes got another car and he's not interested anymore. Its a job for someone else, if theres a someone else that wants it.

 

Its one of those things, Its 250 quid, so its scrap money to anyone who wants to give it a go, but I suspect no one will for the same reasons he doesnt.

 

Its unfortunately one of those cars that everyone (including me) wants "someone else" to take on and save

[CortinaDave]

Worth a final bump...

[Partridge]

I posted on XJ40.com about it asked a few XJ40 nuts if they wanted it...I did try LOL.

[Lankytim]

Has this been saved then?

[Partridge]

No as far as I know, Tim.

[Rocket88]

Stupid question......have you tried changing the oil............ex other half had a V8 Jag which wouldn't start...............changed oil [after advice from t'internet] and it burst into life....apparently if oil gets too thin, hydraulic tappets won't pump up.

[Pillock]

I too apologise for being a bit pushy about getting it going, I didn't realise the effort and expense that had already been put in.

 

GLWTWI

 

(Good luck with the weigh-in)

[ChinaTom]

I had this problem on my V12 - 2 specialists couldn't solve it. Took it to J-Cats in Norwich, and they spent 3 minutes cleaning out the fuel filter which had blocked almost completely. Key in, fire up, off I went. 

 

This would be too nice a car to weigh in as is. At least put a set of scrappy steelies on it and get some coin back for the wheels. You may see a few quid for the number plate surround at the back and the S model specific trim.

[Partridge]

Hopefully it will be parted out before it's squashed - parts are always a positive thing at least.

[Lankytim]

It says NOW SOLD in the title now though?

[Partridge]

That was from when Studebaker Hawk sold it first time around, mate.

[Lankytim]

Oh, soz, err,

 

Carry on then.

[Partridge]

I will let you off this one time.

[Lankytim]

I've got the horn for this big time. But stuff e.t.c.

 

Now the Multipla situation has stabilised I suppose I need to get cracked on with the beautiful Audi coupe on the drive.

[The Reverend Bluejeans]

parted out

I believe you meant to say 'broken for spares'.

 

Never, ever use that other phrase again.

 

That will be all.

 

On the Jag, there is an earth that rusts away from the bulkhead, drivrrs side behind the upper sound deadening. If the pump runs but the injectors don't it'll be something like the fuel pump relay. This is where you need a wiring diagram to see where they get power and a signal from.

 

I'd weigh the fucker as well.

[Partridge]

I mostly say broken for spares, but I try and varity from time to time.

[The Reverend Bluejeans]

Good. You would have gotten into big trouble young man.

 

However, 'spares or repair' the the 1984 Thames Valley Trader slogan of the year* and the true standard bearer of the shiteist movement.