Hi all

ive got a 2001 XK8 due for MOT today

got it out of the garage last night so I didn’t have to shift stuff round first thing this morning. Started first time and ran it for 5 mins with no issues before parking.


this morning, it cranks, the rpm needle moves very slightly whilst cranking but it won’t fire at all.

there is fuel in it, it’s like the immobiliser is on.

I can open the car on the key fob, but sometimes that doesn’t work if I haven’t driven it for a while, I might have to open it on the key, put key in ignition and start it, then the key fob goes back to working again

battery is sound, it’s on a battery conditioner, so it cranks at full speed

any obvious thoughts where to start?

cheers Steve

 

Your fuel pump might have failed. See if there is any fuel pressure at the Schrader valve on the left-hand fuel line whilst the ignition is on.

Can you hear the fuel pump running when you turn on the ignition? Ask someone to listen to the side of the fuel tank in the boot. If it's silent in there, then you need a new pump. Not a difficult job with a coupe but rather more tricky with a convertible.

Richard

 

Hi Richard

Thanks for that I'll check it later on then. I didnt know if there was a fuse for the fuel pump I might need to check? Seeing as the car seems to have more fuses than any other vehicle Ive ever known it would be logical for it to have a fuse!

Cheers

Steve

 

It's fuse 7 (20A) in the boot fuse box next to the battery. I doubt whether the fuse has burned out as it's usually the pump itself (which is inside the fuel tank) which fails. If the fuse has failed, I would expect a replacement to blow as well, but it's definitely worth checking.

Richard

 

Thanks Richard

 

I'd think bore wash would be a suspect with your description.
Does it seem to be turning over faster than normal?

 

I’ve no idea what bore wash is but no I don’t think it’s turning over faster than normal

 

Bore wash is a possibility when these engine are started and then stopped a few seconds later and then restarted. I always let mine run for at least 5 minutes to prevent this so if yours was running for 5 minutes then it seems unlikely. However, try and start it again now a day or two has passed. If it does start, then let it run until the engine is up to temperature.

I seem to recall that turning over the starter motor with the throttle fully depressed can be used to improve compression after too much fuel has been injected but you would need to read up on this as that's going back a few years.

Richard

 

Totally depressing the throttle shuts off the fuel supply. Cranking the engine for a few seconds several times with the pedal at the floor allows oil distribution on the cylinder walls.

 

bore wash is only the beginning of your journey into the esoteric world of Jaguar pitfalls.

“…Grasshopper, the road to knowledge has many twists and turns that one cannot see beyond if standing still….”
Master Po

 

I knew of the “don’t start it and switch it off before it’s warmed up” but didn’t know the phrase that applies to that.

my jaguar journey has already had a few twists but it’s part of the entertainment value! I’m waiting for someone to have a listen for the fuel pump as my hearing is through a cochlear implant so I’m not sure what I’m listening for and can’t pinpoint a sound source. I don’t think there’s a sound at all though so it may well be that the fuel pump has failed. The fuse is OK

Hopefully will get somewhere tomorrow now

 

You totally get it. Once these bugs are ironed out I know you’ll enjoy your car.

 

OK so there are no sounds from the boot area, whether the ignition is on or off. Ignition on would be at the system check level, where the next stage is the spring turn to engage the starter.

With the ignition on, there is a whirring sound coming from the engine compartment but we can’t identify what that might be coming from.

Im erring towards the fuel pump having failed - is this something that can just fail completely and instantly? I started the car, let it warm up to come out of the blue sector, drove it round to the front of the house and parked it and switched off. The following morning, it just cranked. Not firing in any way at all.

 

It is not unusual for the fuel pump to fail in that way. The XK model which followed our XK8 was equipped with two fuel pumps as Jaguar's solution to the problem.

The acid test would be to depress the middle of the Schrader valve which is on the left hand fuel rail on the top of the engine. You need to remove the engine cover on the passenger side (UK cars) and look for the pipe just under the cover which runs from the back of the engine to the front and then goes across to the right hand side and runs back along to the back of the engine.

On the passenger side pipe, near the front, you should see a Schrader valve, just like the inflation valve in the tyres, with a plastic cover on it which you need to remove. The cover might be red or blue unlike the black ones in the tyres but it could be black. If you press the middle part of the valve with a small screwdriver or similar, as if you were letting the air out of a tyre, you should see a spray of petrol coming out. If there is no spray with the ignition on (check level), try it whilst someone is cranking the engine for a few seconds. The petrol should be around 50 psi, so a bit more than a car tyre, but nothing dangerous and it should produce a fountain of petrol for as long as you keep the valve depressed.

Just make sure that any petrol doesn't spray into your eyes .... although, in this case, I don't think there will be any spray which definitely means that the pump has failed.

Richard

 

When these cars sit for long periods of time (could be weeks, could be months), the fuel pump is a well-known failure item. The best way to keep your fuel pump alive is to drive the car on a regular basis. That goes for the rest of the components in these cars as well (especially the battery). If you drive the car regularly, it stays happier and healthier for much longer periods of time....

 

no pressure at the schrader valve either with the ignition on or cranking so it’s the pump then.

my next question then would be, as a decent diy practical bloke, is it a relatively simple job of swapping it out or is it a send to the garage and let the pro’s do it? it’s actually in the fuel tank I think I’ve read?

 

A couple of questions for you will help decide.
How much dexterity do you have and do you have a nice warm place to get the rear a good ways up in the air??
Lots of write ups, in fact a resent one and all the in and outs ways to get the pump installed.
If a coupe, then going through the speaker has worked well for most, do a thread search on it.

 

Wayne is correct. If you have a coupe the it's a relatively simple matter, albeit quite fiddly, of accessing the fuel pump through the subwoofer speaker hole in the rear parcel shelf. If there is a speaker in there, you will have to remove it whilst you do the pump swap.

If you have a convertible, then moving the fuel tank is the approved method of accessing the fuel pump. However, this needs good access under the car as it needs the fuel line/s to be disconnected from the front of the tank to allow you to pull it back into the boot area to allow access to the top. Disconnecting the fuel lines is a difficult job as access is very poor and it really needs a special tool or a home-made version of the special tool. I would suggest that you need to be an experienced DIY mechanic with a good selection of equipment (axle stands at least) before you consider this.

I believe that there is an alternative method whereby you cut an access hole in the back shelf of the convertible and then use the coupe method. I have used a similar method to change the differential oil in my XK8 but the fuel pump replacement is more difficult. There are write ups of both methods on the web.

Richard

 

I’ve got a coupe so I will read up on remov8ng the speaker and going in that way. I’m not the most compact of people either so getting into the back to do it will be a challenge in itself!

really appreciate the guidance on this from everyone - thanks

 

taken out the front seat. Comes out fairly easily, and you’ll have a little more elbow room.

Z