Engine wont fire

[dhdove]

Irisphoto

Sorry I don't have a manual for your motor, but I would guess(?) it's probably similar in outlay to the six cylinder cars..........crankshaft sensor will be directly above the crankshaft where it exits the front of the block. Crankshaft extension will have blocky teeth on it with one bigger than the rest, sensor "sees" the big one and feeds crank position to the ECU for ignition etc. info.

V12 owners - if I am talking rubbish here please put me out of my misery quickly

DH Dove

[ptjs1]

Phil,

On a 6 litre, the crank position sensor is mounted at the bottom of the front timing cover - two small bolts mount it to a small boss.

If it is the petrol or ignition ECU's, you'll be looking at second-hand ones as you can't buy either new for the early factory 6 litre cars at present.

Good luck

Paul

[irisphoto]

Hello Lads,. Ok i did the spark test. I held the HT lead above the spark plug (still in the engine) and fired it up. Still on luck. Any suggestion would be helpful on where I go next. I found the crankshaft sensor, (and part number too) also when looking at the HT leads the rubber was badly cracked. So I might need a new set of HT's

Thanks You for the help so far

Oh yeah, we don't have a Jaguar garage here on the isle of wight, and Florence (car's name) is not due for a service for a few months. Which I hope to do, But I go to say I dont like getting under her. But happy if Im on top !!!:)

[irisphoto]

Hello lads, ok, I did it again this time spark plug out. I got a yellow-ish spark this time around then the battery died. So I do have a spark. Mr kelsham said the spark should be blue but mine was not, do you think the sparks plugs need of a change?

I guess I will have do buy a crank sensor, Its cheeper that a EUC.!!!

[dhdove]

Irisphoto

Whoa! slow down...........you have now proved that you have a weak spark at one plug (and the battery is nearly/flat)............under normal circumstances a weak spark at all plugs should start the engine and the car should drive ( although perhaps not very well).

If it were my car I think the next way to go is to take out several plugs and put some fuel down the plugholes.....if it fires and tries to run you definately have a fuel problem.

HOWEVER.........I am concerned that you are working at the extremes of your experience...........you may end up doing more damage than good

I would advise that you get a reputable mechanic who is familiar with Jaguar engines to look at it, OR is there anyone on the Forum who is close enough to help? I'm sorry but the IoW is just a tad too far for me to pop down and assist.

Please do not let your enthusiasm overcome your experience......in the long term it could prove expensive

As they say," a stitch in time saves nine".

Good Luck

DH Dove

[almcl]

In addition to what DHDove has said, a weak spark at the plug is unlikely to be the fault of the plug.

Changing them won't hurt but it's unlikely to cure the problem.

If dramming the engine (as suggested) and recharging the battery doesn't cause it to fire, try removing the king lead from the distributor and holding it with a VERY WELL INSULATED grip, see what sort of a spark will jump a half inch gap to engine metal. If this spark is similarly weak then the ignition is suspect.

[irisphoto]

Hello everyone. I just like to say thank you for all you help and advice. I went to my local Jag club on monday of which I am a member. To my horror no one knows anything about the V12. Great! Thats a good start. However they did give me some advice which has been said by you lot.

I pulled out plugs, got them to spark. Added some petrol in the holes, it did try to work (Fire up). Cant hear any sound from the pump when the key is turned So I think its the Pump or the ECU, in the boot. I have check the relays, by putting a jumper on it to by-pass the ECU (DVICE FROM THE xjs Bible) If it worked it Must be the ECU thats faulty, but still no luck.

Now My car was resisted in 1993. But the VIN number says its a 1994, can this be right? It makes a big difference as the 1994 model has two fuel pumps, not one! This is the same as the XJRS. I have looked at the Parts & Service Manuals from the JEC but its say only one pump. But I have a up dated jag manual (1994) that says 2.

Can anyone verify this? Cheers Phil

[dhdove]

Irisphoto

Some good progress there I think, when you turn on the ignition you should hear the fuel pump "buzz-up". If you can't I would go for the fuel pump first.

Check that when the ignition is turned on you have 12V at the pump - if so, pump is U/S...from your post you have already confirmed this - you did check 12V feed to the pump?, I presume you jumped 12V direct to the fuel pump - -did you check the earth?

Sounds like the fuel pump is finished.

Borrow or buy and fit a new one See if she fires up

NB I didn't realise any cars had two fuel pumps, those XJRS's must be thirsty beasts....no doubt someone will advise

Best Wishes and Good Luck

DH Dove

[irisphoto]

Hello dh dove, Its a bugger 2 pumps!! I have not tried the earth, but You never know. I also not jumped it. Thats a good idea too. Well it better than £400 ish on a pump.

[dhdove]

Irisphoto

If you have a multi-meter/test bulb (check that it works OK first ) just check whether you've got 12V to the pump with the ignition switched on............if so pump is prob U/S, if not the fault lies elsewhere.

Also, can't believe it's £400.00 for a pump - -it's a generic stock part isn't it?

DH Dove

[ptjs1]

Phil,

There's a number of confusions here. I think someone has been misleading you! (not dh, I think he's helping you!) Let me see if I can clarify one or two of the issues:

You have a 1993 car. It's a 1993 model year, it was made in 1993 and it was registered in 1993.

All standard 6.0 XJSs have twin fuel pumps. Your car has two fuel pumps. The rear pump provides fuel up to about 2500rpm and then the front pump cuts in as well after that. Don't get confused with 6.0 XJR-Ss. They have one fuel pump only.

They stopped making XJR-Ss in 1993 & then they started making standard 6.0 XJSs in 1993. So a 1993 car can be either a XJR-S or a standard 6.0 XJS

If the rear pump has packed up, you might be able to bypass it. I don't know the wiring setup well enough including fuses and relays to know whether you can bypass or swap the wiring around to see if you can get the car to start off the front pump. Have a look at the wiring diags. It might be easier just to pull he rear pump out of the tank and see if it is working.

I'm a bit confused about the parts & service manuals. The JEC don't produce any manuals. The ones produced by Jaguar Classic Parts on behalf of the JDHT are the original Jaguar documents. The XJR-S manual shows only one pump. The standard XJS 6.0 manual shows the two pumps.

I hope that clears up things a bit. One last point: in checking your VIN, I noticed that you have entered your car in the register as a 3.6, not a 6.0. It would be really helpful if you could amend this when you get a moment and also enter in the correct paint & trim codes for your car. Thanks.

Good luck in sorting the problem.

Paul Sinnott
XJS Registrar
Jaguar Enthusiasts Club

[irisphoto]

Hello ptjs, thanks you for your input. XJRS did have two Pumps at the end of its life. You could tell if it had two pumps by 2 black stripes that appear on the petrol tank (vertical, I think)

I did not realize I had put my car as a 3.6 so I will change that. But my car was registered in 1993, however VIN numbers say its a 1993.5, sorry not 1994. My mistake.

The manual I bought from the JEC 12v 6.0L XJS PARTS & SERVICE, It only show one pump. This is why I need to have some understanding if I have 1 or 2 pumps.

I have been looking at Kirby Palm manual. Have you read it? Although its all the XJS 3.6, 4, 5.3, and 6 are covered.

I will let you know how I get on. Cheers !!!

[ptjs1]

Phil,

Tks for this. I'm interested to hear that late XJR-Ss had two pumps. I wasn't aware of this. When the standard 6.0 XJS came out at 1993.5 Model Year it used a new fuel tank that accommodated the twin pumps. So I wonder what tank the previous XJR-Ss were using that could take two pumps? Where did you find out this info? Have you got anything that you can email me? Tks.

I'm not sure which is the 6.0 Parts & Service Manual that you bought from the club which shows the one pump. Any chance that you can send me a pic of the front cover so that I can identify it? If we're selling something that has incorrect info, it's important that we try and correct it. Tks again

Drop me an email anyway and I'll send you the diagram which shows how the two pumps are powered by different control signals, one from the ECU and one based on a speed signal from the fuel pump control module.

Yes, I have got the Kirby Palm book, although it is biased to the 5.3 V12, as you've probably realised. However, it's a great source of general information on XJSs

Cheers,

Paul

[irisphoto]

I will sort it out in the morning-ish, I will PM you with the details, if I can remember where I have seen it all. I have read so much about this... My brain hurts!!

Thanks Again Phil

[masterb]

Hi Iris,
I will just throw my two penny worth in here.
Before you bin your fuel pump, like Mr Dove says try putting a 12v fead directly to it via a battery or small power supply, or you can nick a feed from one of the relays at the drivers side rear Buttress pillars.
Also before you bin your fuel pump check the positive lead on your Battery.
If you follow it down, you will find a small cover on the positive lead and going into this are two positive Taps (leads) they are your normal spade type
connectors, and can come off quite easily, espescially if you have been changing battery or just cleaning in that area.
One of these taps/leads attatched to the positive lead feeds the fuel pump.