Fuel problem?
#1
Fuel problem?
Hi guys.
I had a fuel starvation problem last year with the car stalling etc this was after renewing the fuel pressure regulators. Fast forward to yesterday and the first run out of the season and after swapping the B bank regulator back to the original one. The car ran great all day apart from one incident on the way home when the engine cut out after a second gear run at 3000 odd rpm. I coasted to a halt and the engine started on the third attempt and then ran fine all the way home. Any ideas. I still have the new A back regulator fitted and am tempted to do away with it. Last year I fitted a new fuel pump and fuel filter.
Rob.
I had a fuel starvation problem last year with the car stalling etc this was after renewing the fuel pressure regulators. Fast forward to yesterday and the first run out of the season and after swapping the B bank regulator back to the original one. The car ran great all day apart from one incident on the way home when the engine cut out after a second gear run at 3000 odd rpm. I coasted to a halt and the engine started on the third attempt and then ran fine all the way home. Any ideas. I still have the new A back regulator fitted and am tempted to do away with it. Last year I fitted a new fuel pump and fuel filter.
Rob.
#2
Hi Robbo
Could be the Crank Position Sensor under the Front Pulley, as its been Freezing Cold and Raining almost every day in April, so may be worth Checking the Gap and giving the Gap a Spray of Contact Cleaner
The Gap should be no more than 0.042
I think you had that same problem a few years ago?
Could be the Crank Position Sensor under the Front Pulley, as its been Freezing Cold and Raining almost every day in April, so may be worth Checking the Gap and giving the Gap a Spray of Contact Cleaner
The Gap should be no more than 0.042
I think you had that same problem a few years ago?
Last edited by orangeblossom; 04-22-2024 at 04:20 AM.
#3
Hi OB.
Both the position sensors were renewed last year so don’t think it’s them. When I cranked the engine after the stall on the first two attempts it did try and fire and on the third attempt it started normally and then ran fine. I know when the CPS were playing up the engine would stop and not attempt to fire for around 10 minutes until it had cooled a bit then started and ran fine.
Rob
Both the position sensors were renewed last year so don’t think it’s them. When I cranked the engine after the stall on the first two attempts it did try and fire and on the third attempt it started normally and then ran fine. I know when the CPS were playing up the engine would stop and not attempt to fire for around 10 minutes until it had cooled a bit then started and ran fine.
Rob
#4
#5
Hi Robbo
Maybe the Pins on the Resister Pack need Cleaning
Cleaning the Contacts on the Resistor Pack which can affect the Injectors
Maybe the Pins on the Resister Pack need Cleaning
Cleaning the Contacts on the Resistor Pack which can affect the Injectors
#6
Hi OB
Filters all fine and I have cleaned the resistor pack pins so all should be good there. I think I will delete the A bank regulator renew the fuel filter just in case it’s faulty it’s a non genuine part. I could also put my old fuel pump back in as it’s was working ok prior to swapping out. I only did this as preventative maintenance but it seems not to have worked very well. I must admit I am a bit dubious on the quality of pattern parts having had some crappy bushes in the past.
Rob
Filters all fine and I have cleaned the resistor pack pins so all should be good there. I think I will delete the A bank regulator renew the fuel filter just in case it’s faulty it’s a non genuine part. I could also put my old fuel pump back in as it’s was working ok prior to swapping out. I only did this as preventative maintenance but it seems not to have worked very well. I must admit I am a bit dubious on the quality of pattern parts having had some crappy bushes in the past.
Rob
The following users liked this post:
Greg in France (04-22-2024)
#7
Hi Robbo
Try By-Passing the Thermostatic Wax Stat on the Fuel Rail with a Single Piece of Polythene Tube
Not needed in the UK with our Climate! (Lol) as any sort of Blockage on the way to or from the Wax Stat could affect the Vacuum and make your Car run 'Rich' and as a result cause Starting Problems
I took mine out altogether, as there is nothing behind it (its just blocked off)
I'm actually thinking this could be your 'Best Bet'!
Easy to do, so gotta be worth a Shot
By-Passing the Wax Stat Thermostatic Valve
Try By-Passing the Thermostatic Wax Stat on the Fuel Rail with a Single Piece of Polythene Tube
Not needed in the UK with our Climate! (Lol) as any sort of Blockage on the way to or from the Wax Stat could affect the Vacuum and make your Car run 'Rich' and as a result cause Starting Problems
I took mine out altogether, as there is nothing behind it (its just blocked off)
I'm actually thinking this could be your 'Best Bet'!
Easy to do, so gotta be worth a Shot
By-Passing the Wax Stat Thermostatic Valve
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#8
#9
Hi Robbo
On some Non OEM Fuel Pumps, depending on where it was made, the Positive side is marked Negative and the Negative side marked Positive, so that the Pump can be running in reverse!!!
I've got one of those on my Car at the moment, so all I did was to swap the Positive and Negative around and its been working OK ever since
So maybe that's why your Original Fuel Pump works and your New one doesn't? (This was a Hot Tip from 'Grant' The Wizard of OZ')
Also I only use 'El Cheapo' Fuel Pumps from ebay £30 instead of £130 as they are all Generic and fitted to loads of Cars
Only recommended for Pre-Facelift V12's like we've got, with external Fuel Pumps
Also I've moved my Fuel Pump from underneath the Battery (no re-plumbing required!) So that I can Change it by the Side of the Road if I have to, as I always Carry a Spare one in the Boot/Trunk
Alex
On some Non OEM Fuel Pumps, depending on where it was made, the Positive side is marked Negative and the Negative side marked Positive, so that the Pump can be running in reverse!!!
I've got one of those on my Car at the moment, so all I did was to swap the Positive and Negative around and its been working OK ever since
So maybe that's why your Original Fuel Pump works and your New one doesn't? (This was a Hot Tip from 'Grant' The Wizard of OZ')
Also I only use 'El Cheapo' Fuel Pumps from ebay £30 instead of £130 as they are all Generic and fitted to loads of Cars
Only recommended for Pre-Facelift V12's like we've got, with external Fuel Pumps
Also I've moved my Fuel Pump from underneath the Battery (no re-plumbing required!) So that I can Change it by the Side of the Road if I have to, as I always Carry a Spare one in the Boot/Trunk
Alex
The following users liked this post:
Greg in France (04-22-2024)
#10
Hi Robbo
Pic of my Fuel Pump relocation here, so I can change it by the side of the road if I have to
Fuel Pump relocation to make it easy to get to, if I have to change it by the side of the road
Alex
Pic of my Fuel Pump relocation here, so I can change it by the side of the road if I have to
Fuel Pump relocation to make it easy to get to, if I have to change it by the side of the road
Alex
#11
The following users liked this post:
Greg in France (04-22-2024)
#12
The following users liked this post:
JJS- Florida (04-26-2024)
#13
#14
#15
Hi Robbo
On our UK V12 Cars
Facing the Boot/Trunk with the Boot Open the Main Relay and The Fuel Pump Relay are behind a Piece of Carpet Trim, just to the right of the Gas Strut behind a Big Plastic Cover, that you can bend back far enough to get you hand in to Change them
The Main Relay is in the Red Holder and the Fuel Pump Relay is in the Black Holder
The Fuel Pump Relay won't work unless the Main Relay (in the Red Holder is also working)
These Two Relays are NOT interchangeable because one of them has a Diode and the other one does not (But this is clearly indicated on the Relay)
There is a Photo of where they are halfway down this Thread
Location of Fuel Pump Relay and Main Relay
On our UK V12 Cars
Facing the Boot/Trunk with the Boot Open the Main Relay and The Fuel Pump Relay are behind a Piece of Carpet Trim, just to the right of the Gas Strut behind a Big Plastic Cover, that you can bend back far enough to get you hand in to Change them
The Main Relay is in the Red Holder and the Fuel Pump Relay is in the Black Holder
The Fuel Pump Relay won't work unless the Main Relay (in the Red Holder is also working)
These Two Relays are NOT interchangeable because one of them has a Diode and the other one does not (But this is clearly indicated on the Relay)
There is a Photo of where they are halfway down this Thread
Location of Fuel Pump Relay and Main Relay
The following 2 users liked this post by orangeblossom:
Greg in France (04-23-2024),
Robbo D (04-23-2024)
#16
The following 2 users liked this post by Robbo D:
Greg in France (04-23-2024),
orangeblossom (04-23-2024)
#17
Hi Robbo
Pic of my Fuel Pump relocation here, so I can change it by the side of the road if I have to
Fuel Pump relocation to make it easy to get to, if I have to change it by the side of the road
Alex
Pic of my Fuel Pump relocation here, so I can change it by the side of the road if I have to
Fuel Pump relocation to make it easy to get to, if I have to change it by the side of the road
Alex
Cheers
Alfredo
#18
Hi Alfredo
Basically all I really did was to reposition the Fuel Pump Holder, so that it was no longer underneath the Battery Tray and if I can find the Photo you will see that it is very easy to do
But if you are Changing the Pump then you have to be Careful and don't do it inside your Garage, do it outside to be on the Safe Side and then only if you know what you are doing
Including disconnecting the Battery First and having a Fire Extinguisher Standing by in case the worst should happen!
Then Clamp the Fuel Hoses before you disconnect them, as the Fuel Pump is Gravity Fed and if you don't know what you are doing then you could have Petrol Flooding everywhere
So if you are in any doubt, it may be best to leave it as it is
As for Moving the Pump over, as opposed to Changing it completely, from what I can remember I just re-positioned the Fuel Pump without the need of disconnecting anything
The Photo should explain it all if I can manage to find it
Basically all I really did was to reposition the Fuel Pump Holder, so that it was no longer underneath the Battery Tray and if I can find the Photo you will see that it is very easy to do
But if you are Changing the Pump then you have to be Careful and don't do it inside your Garage, do it outside to be on the Safe Side and then only if you know what you are doing
Including disconnecting the Battery First and having a Fire Extinguisher Standing by in case the worst should happen!
Then Clamp the Fuel Hoses before you disconnect them, as the Fuel Pump is Gravity Fed and if you don't know what you are doing then you could have Petrol Flooding everywhere
So if you are in any doubt, it may be best to leave it as it is
As for Moving the Pump over, as opposed to Changing it completely, from what I can remember I just re-positioned the Fuel Pump without the need of disconnecting anything
The Photo should explain it all if I can manage to find it
#20
Hi alpecsa
Here is the Full Post on my Fuel Pump Relocation XJS V12 Pre-Facelift
Fuel Pump Relocation
Also I found the Photo
Hope This Helps
Alex(OB)
Here is the Full Post on my Fuel Pump Relocation XJS V12 Pre-Facelift
Fuel Pump Relocation
Also I found the Photo
Hope This Helps
Alex(OB)
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