Hi, I'm awaiting delivery of a pressure test kit. Will let you know the results.

 

Hi all, quick update. Took the car out this morning and it quickly played up. Within a few minutes of driving it would accelerate and crept along at 15mph. When you put your foot down it just wanted to die. I have bought a fuel pressure gauge but I'm now waiting for some fittings. I've got a new fuel filter to try too.
Those trims show you may have an air leak. Do they drop near zero if you rev to (say) 2500 when parked?
When stationary i held the revs at 2500rpm. These are the fuel trims I got. No2 slowly increased but the reading shown is the max it went too. At tickover they were both equal.

 

Can you explain a bit more about those two photos? Were they both taken at 2500 rpm, or is one at idle and the other at 2500?

Have a look at this thread which is a good introduction to fuel trims if you haven't already seen it. JagV8's post #12 explains why you are looking for the difference between idle and 2500rpm:-

https://www.jaguarforums.com/forum/g...ed-quiz-49317/

 

Thanks for that. I will have a good read of it.

 

Morning all,
I've replaced the fuel filter again this morning. On both occasions I've depressurised the system by pulling the fuse and letting the engine stop. Despite this fuel continued to syphon from the tank, which i didnt think it should do. Is this a sign of something wrong?
many thanks in advance

 

That didn't happen when I changed mine, but others have reported on here that fuel did continue to syphon out - maybe you just have to leave the engine off for longer to allow the fuel pressure to drop. The real test of whether or not everything is ok is going to be what the pressure is at the Schrader valve on the fuel rail - as you have discovered a lot of these pressure gauges don't come with the Schrader fitting, which is a PITA.

 

Ok ta. Gonna try testing the pumps tomorrow.

 

Tested both pumps this morning using a jumper wire and they are both working. ?????

 

And the fuel pressure at the Schrader valve?

 

Still working on it.😀

 

Good afternoon,
while I am waiting for the schrader valve I have carried out a couple of extra tests.
I started the car and let it run for 10minutes or so. I then pulled the relay on number 1 pump. The car stalled. While still out i tried to restart the car , which it did immediately only on pump number 2. When fully warm i revved it to the limiter aroubd 2500/3000rpm. No issues running just on pump 2. Only thing i noticed was the relays were warm after replacing number 1 and letting her run a while.
Questions!
1, Does this not point to a different issue to fuel supply? As the car revved ok and has no issues when idling, will I not get therefore get a good pressure reading ?
2, Any suggestions as to other avenues to explore?
Thanks in advance for any more assistance

 

Hi all, I've been trying to connect to the schrader valve and after a couple of wrong fittings and late deliveries I decided to go the hillbilly route as they say. I removed the schrader and connected a fuel line in direct. I secured it with a clamp but still wasn't comfortable with it but needs must. Anyway it didn't leak and here's what happened!
At tickover after coming off cold start the pressure was steady at around 35 psi.
I had quite a long length of hose so i could reach the windscreen and dont know if this had any bearing on the reading.

I strapped the guage to the screen and went for a short drive. I didn't go far because I wasn't comfortable with the set up. However as previously noted the car was dying out under acceleration, and also deceleration approaching junctions or roundabouts. In the shortish journey it played up three times, each time the fuel guage fell away from 30/35 psi to 10/15psi. On one occasion it nearly stalled which is also what it has been doing.
Upon my return I left the guage connected and it was holding pressure but dropping very slowly.
would you learned people think the pumps are the culprits? Is the fuel pressure regulator ok as it was maintaining pressure after being turned off?
As always many thanks for your assistance.



It only hit 40 psi once while out. 35psi on tickover and dropped to around 32psi when revved to the limiter at standstill. So more revs meant bit less pressure.

 

sorry to say, the pumps are usually the culprit

Z

 

Thanks for that zray. It's been looking that way from what you and dibbit said previously. They were done by p.o about 3 years ago then sat for nearly 3 years.
I will start making some plans. I'm not too upset as I've been going through the car and will know where I stand when there done 👍

 

Once you get the car moving, try to drive it’s often as you can. Left to sit they don’t fare well.

Z

 

It looks like you have definitely found the issue - you might want to do a few more tests before changing both pumps. If you have the coupe you can get access to the top of the pumps from the subwoofer in the parcel shelf. If you have the convertible you might consider cutting your own hole to get access. I think I would want to be certain the pumps are getting a solid 12v and ground before removing them - ideally connect your multimeter across the pump connections at that parcel shelf hole (i.e. as close to the pumps as you can get) and see what readings you are getting as you are driving. You can rule out a bad connection by doing this.

Another thing to try is to pull the relay for pump number 1. The car should switch to using pump number 2. See if you get the same PSI readings.

I would also try more fuel injector cleaner in the tank - you might be lucky if the pump is gummed up, this will help.

 

Hi again and thanks for the advice. Unfortunately it is the convertible. I've just finnished moving things round in the garage and got the car in position. I've weighed the methods up and have decided to remove the tank. I can touch the pipe connectors underneath and am ready to do battle! As someone has been there before me just on 3 years ago, I would like to go through things and try and make sure everything is correct and I know what is in there if that makes sense. I was wondering if removing the fuel sender before taking the tank out would tell me anything meaningful?
Also any suggestions for draining the rest of the fuel? The low fuel light is now on. I was going to try a thin pipe.
Any other suggestions gratefully accepted. Thankyou.

 

My only advice is to check the wiring is ok before changing the pumps. Always check the simple stuff before deciding it's the complicated bits.

 

Made a start this morning. Decided to drain the tank by jumping the relays. I noticed that I could hear each pump working as I have said before, however fuel was coming out of pump 1 inconsistently ie surging. When I switched to pump 2 nothing came out at all. That typifies how the car has been running. I'm thinking maybe the filters are clogged on the pumps? There fun the fuel lines. See me being a while!

 

Update, i think I've found the problem.


any suggestions on tank cleaning and sealing? I had my xjs tank done with a company in Newcastle and very happy with it i was. Might try them again. Just pleased I can cross this off.