TD5 Fuel Pressure problem

This site contains affiliate links for which LandyZone may be compensated if you make a purchase.
Andy Springthorpe said:
Hi folks, i have reviewed this thread and just need a little advice please. I have a non starting issue and here is where i am at... (apologies for long post)
I have a 2001 TD5 90 @ 120k miles. I have replaced the injector loom, done the injector washers, cleaned the red ECU plug, fitted a new filter housing and filter. I have replaced the in line air bleed valve with a genuine Land Rover item just to eliminate this as a problem as at £19 it was cheap enough.

I have cleaned the crank position sensor and plug, as this was coated in oil (not diesel) it shows no faults through diagnostics.

I have no diesel in the engine oil and all filters and oils are brand new.

I have connected a pressure gauge to the temp sender outlet on the FPR and get the following....

1. When purging the system after connecting the gauge i get a steady 4 bar when the pump is running and can hear fuel gushing through the system. However, when the pump cuts out, the pressure drops to 0.75 bar in less than 1 second. As soon as the pump starts a new cycle, it goes straight back to 4 bar.
2. Once the purge cycle phase is complete with ignition still on i get around 0.75 bar. If i turn the ignition off and back on it goes back to 4 bar, until the pump shuts down, pressure dropping straight back to 0.75 bar.
3. With the gauge still connected, i crank the engine and the pressure drops to 1.5 bar before the gauge fluctuates wildly between 1.5 to a maximum of 3 bar. The LR does not start, although occasionally it try's It will eventually start up but it takes a lot of cranking. Once running it is smooth and goes well.
However, if i switch it off it won't start

Incidentally when the pump is running either from cold or with a hot engine, i do not get any gurgling sounds suggesting air in the system. The only exception is when i connected the gauge or replaced the air bleed valve, where I introduced air into the system.

Thoughts please guys, is it my FPR or as i fear my Fuel pump?
Thanks
Andy
Click to expand...
It may be the fuel pump, but I would suspect the fuel pressure regulator on the back left hand side of the head, it ought to hold the pre sure at close to 4 bar after the pump has made this pressure and there is no demand for fuel as the engine is not running.
 
Ok, so i got hold of another pump, not brand new but as good as. I did notice though that when you turn ignition on and BEFORE I crank the needle shoots straight to 4 bar. Not gradual or smooth, just straight to 4 bar. (same for both pumps) The car still wouldn't start and when cranking i got a pressure drop to 1.5 bar fluctuating then to 3 and occasionally 4 bar, same as other pump.
I then tapped in to the fuel pipe that enters the FPR. With ignition on the needle goes straight past 7 bar (gauge limit) until the needle hits the stop pin. Best guess maybe 9 bar. Reconnected fuel line and tapped back into temp sender on FPR. Ran a purge and she eventually started. The gauge showed 4 bar +/- 0.5 and maintained this even when i revved the engine. I switched off and it struggled to restart, although warm. When cranking same pressure drop but once running maintains a steady 4 bar.
All the Youtube vids related to TD5 fuel pressure show ignition on gauge climbs to 4 bar and no pressure loss when cranking or engine running.
Could i be experiencing a voltage drop as starter draws current and pump doesn't get full juice from battery as maybe battery knackered? Or is my FPR knacked?
Advice please guys as a lot of head scratching going on here!
 
below 10 volts at the batt while cranking is a fail but without having the batt drop tested .. using a multimeter is just a rough estimate .when the ecu sees to much of a voltage drop the injectors wont enable electronically
also change out the fuel pump relay and fuse ...the relay maybe getting lazy or possible a lazy fuse ....or the power cables entering the relay box are loose or bad connections
try and hook up bat to a set of jump leads to another vehicle to give that extra batt power at the same time make sure there are no loose connections on batt and starter

whenever measuring fuel pressure its allways best to measure the fuel returning out of the head (spill pipe ) ie the front of the head and not the return side of the regulator

for example if the screen gauze blocks up inside the head from carbon build up like mine was the regulator still bypasses fuel as normal .as the fuel temp sendor is actually fuel return... but still doesn't tell you there is pressure in the cylinder head .
in other words you could still have good pressure either side of the regulator in going and out going ...but is there any fuel running through the head
 
Last edited:
ozzyboydeano said:
below 10 volts at the batt while cranking is a fail but without having the batt drop tested .. using a multimeter is just a rough estimate .when the ecu sees to much of a voltage drop the injectors wont enable electronically
also change out the fuel pump relay and fuse ...the relay maybe getting lazy or possible a lazy fuse ....or the power cables entering the relay box are loose or bad connections
try and hook up bat to a set of jump leads to another vehicle to give that extra batt power at the same time make sure there are no loose connections on batt and starter

whenever measuring fuel pressure its allways best to measure the fuel returning out of the head (spill pipe ) ie the front of the head and not the return side of the regulator

for example if the screen gauze blocks up inside the head from carbon build up like mine was the regulator still bypasses fuel as normal .as the fuel temp sendor is actually fuel return... but still doesn't tell you there is pressure in the cylinder head .
in other words you could still have good pressure either side of the regulator in going and out going . but if the cylinder head is blocked or choked you may only see 1 or 2 bar of pressure in the cylinder head.... this would be enough to run but maybe a hard starter as it needs more fuel on demand on start up
Click to expand...
To test the pressure should i connect to the fuel return to the filter then or is it better connecting between FPR and fuel cooler?
 
Andy Springthorpe said:
To test the pressure should i connect to the fuel return to the filter then or is it better connecting between FPR and fuel cooler?
Click to expand...
You need to be upstream of the FPR which is a pressure regulator designed to hold 4 bar and then open when pressure goes higher leaking the fuel back to the low pressure side of the in tank pump, this should then close as pressure falls and hold 4 bar in the common rail in the head so the injectors are supplied with pressurised fuel at their intake. I know there are some diagrams of the system which make it prety clear, I've seen them posted on here.
 
Andy Springthorpe said:
To test the pressure should i connect to the fuel return to the filter then or is it better connecting between FPR and fuel cooler?
Click to expand...
neither..... your missing the whole point if the head is blocked there will always be a fuel return its the nature of the system. as the regulator is still doing it job
in your case could be a flow issue and not pressure issue

during your episode I have also did some testing today to refresh my memory .. I have disconnected both fuel pump fuse and relay..so fuel pump in the tank does certainly not run with zero fuel pressure reading on my gauge ..yes its an oil gauge being used.... but this was the closest gauge I found that was in scale laying in shed

here is the vid from today .. I disconnected the fuel pump electronically ... I had no issues apart from lack of power and a slight diesel knock and a surge .... least I know in future if my fuel pump fails I can limp home
my fuel pressure gauge is the top gauge on the pillow ..this is a mechanical gauge that reads spill pressure from the front of the head

 
Last edited:
@ozzyboydeano

Did you record what the pressure was with the fuel pump relay and fuse fitted and engine cranking and running? just for clarification as the recent OP had done this.

Also, I take it if you have connected in line into the pipe from the front of the engine that you have a 10P engine , not sure what the recent OP has on his, it is a 2001 90.

Cheers
 
neilly said:
@ozzyboydeano

Did you record what the pressure was with the fuel pump relay and fuse fitted and engine cranking and running? just for clarification as the recent OP had done this.

Also, I take it if you have connected in line into the pipe from the front of the engine that you have a 10P engine , not sure what the recent OP has on his, it is a 2001 90.

Cheers
Click to expand...
hi
can confirm as I have had my fuel pressure gauge installed for some time when I first installed I was seeing 60 to 62 psi
unfortunately I work in psi not bar
one year later
ignition on cold engine 57 58 psi
engine start up drops to 55 then back up to 57 /58 idle cold engine
engine warm fuel pressure drops to 55 on idle and full boost

yes your correct I'm measuring spill pressure ie front of the head not fuel pump pressure
 
Last edited:
neilly said:
So are you inline with the head return pipe before it gets to the FPR? or is there a plug you have removed? As you do not say if you have a 10P or 15P.

Cheers
Click to expand...
I have drilled and tapped into the fuel regulator
the same gallery the front spill pipe leads to
 
Thanks for the info and the video, looks nice there mate! I am assuming that your D2 was running on the fuel contained within the head by the FPR?
My engine is a 10p one, so i have been taking pressure from temp sender which shows 4 bar/58psi ingnition on and the same when running including revving engine. I have plus 7 bar/100 psi if i connect to feed from pump with ignition on. Upon cranking drops to 1.5 - 3 bar fluctuating.
Today i have checked the "electrical power" supplied to the pump when ignition on and then cranking, based on Ozzys advice. With no cranking 13.5 volts but drops to 10/11 volts when i try to start her. I then tried a jump start from a 2 litre diesel car and she started! I have now bought a new relay and HD battery. I must say I didn't think it was a lazy starter/battery issue as it cranked ok IMO, however definitely could hear/tell the difference from jump start. Thanks again for support i am grateful.
Regards
Andy
 
neilly said:
So are you inline with the head return pipe before it gets to the FPR? or is there a plug you have removed? As you do not say if you have a 10P or 15P.

Cheers
Click to expand...
sorry mate
unfortunately I don't know what engine is in mine unsure I have never really looked into that side of things
where can I tell if its a 10 p or 15 p
all I know its a 2002 d2
the spill pipe from the front of the head goes back into the FPR
 
Hi @ozzyboydeano

Well, I would check the engine number that is stamped on the block first, also on the V5 over here it states the engine number. Not sure what your paperwork states.

Have a look here, this is obviously for a UK vehicle as it shows EU3 changes . I assume they made the same changes on all vehciels globally, but you knwo what they say about assumptions.....LOL.
upload_2017-6-25_6-59-9.png


Cheers
 
neilly said:
Hi @ozzyboydeano

Well, I would check the engine number that is stamped on the block first, also on the V5 over here it states the engine number. Not sure what your paperwork states.

Have a look here, this is obviously for a UK vehicle as it shows EU3 changes . I assume they made the same changes on all vehciels globally, but you knwo what they say about assumptions.....LOL.
View attachment 126222

Cheers
Click to expand...
thanks neily I haven't checked any engine numbers and log books will be hidden away some where around the house LOL place is upside down at the moment as where in the process of packing

but the fuel diagram matches my lay out

when I had my FPR off I sat and studied the flow and worked out what gallery is for what
I have found that this set up some of the fuel goes back to the engine to be used on fuel demand ...so when ONE has injector copper washer issues the screen gauze can block up from carbon deposits before the main fuel filter ... its a bit like 50 50 some fuel goes back through the head while some goes back as return back to tank

however its been awhile ... when I purchased the FPR gasket there are 2 types so I bought both just in case ...there is no difference in gaskets for both engines

this was one of the main reasons I T into the spill pipe on the FPR because if the screen gauze blocks completely in the cylinder head the FPR still has pressure on both sides as it wont notice a blockage in the cylinder head
 
Andy Springthorpe said:
Thanks for the info and the video, looks nice there mate! I am assuming that your D2 was running on the fuel contained within the head by the FPR?
My engine is a 10p one, so i have been taking pressure from temp sender which shows 4 bar/58psi ingnition on and the same when running including revving engine. I have plus 7 bar/100 psi if i connect to feed from pump with ignition on. Upon cranking drops to 1.5 - 3 bar fluctuating.
Today i have checked the "electrical power" supplied to the pump when ignition on and then cranking, based on Ozzys advice. With no cranking 13.5 volts but drops to 10/11 volts when i try to start her. I then tried a jump start from a 2 litre diesel car and she started! I have now bought a new relay and HD battery. I must say I didn't think it was a lazy starter/battery issue as it cranked ok IMO, however definitely could hear/tell the difference from jump start. Thanks again for support i am grateful.
Regards
Andy
Click to expand...
glad you your getting somewhere as I also nearly replaced a starter motor a few months back ..mine was clicking though and randomly it would start

I ended up climbing underneath ... jump leads to the starter giving the starter motor its own power direct power (from another source) ... turned out to be a loose connection on the main positive batt terminal

I was very surprised myself the engine ran for so long without a fuel pump
I even went up hill a few times to load her up she lacked of power though and feel a surge ....I'm guessing the injectors where creating there own suction pull type when hammered down by the cam shaft just enough fuel for the engine to run and start ..to be honest I really don't know ...but the amount of driving I did on the vid this should of used up the fuel inside the head

to learn more on this engine myself doing silly tests I also get to know my own vehicle or become more custom to how it reacts

I would like to know what is the desired low fuel pressure results in a diesel knock just wondering how many people have renewed injectors because of a diesel knock or lack of power
 
Last edited:
Update...
I fitted a brand new HD battery without drama. When i went to change the fuel pump relay, I disturbed the main power relay in the process and the brown live wire literally fell off the spade! It was only held on buy a few strands! The wire was green as was the relay terminal. I cleaned everything and reassembled it. The LR started!
I will be fitting 2 new relays and 4 new glow plugs to be 100% certain i have eliminated everything. I will update next week.
Thanks again for the advice
Andy
 
Andy Springthorpe said:
Update...
I fitted a brand new HD battery without drama. When i went to change the fuel pump relay, I disturbed the main power relay in the process and the brown live wire literally fell off the spade! It was only held on buy a few strands! The wire was green as was the relay terminal. I cleaned everything and reassembled it. The LR started!
I will be fitting 2 new relays and 4 new glow plugs to be 100% certain i have eliminated everything. I will update next week.
Thanks again for the advice
Andy
Click to expand...
the vapours of the old battery has gotton to the relay box I would remove all fuses and relays and spray the whole relay box with wd40 or spray of choice... to give the box at least half a chance for later or other future issues

the main power wires entering the relay fuse box I renewed mine and also lengthened them I added in an isolator switch to the roo bar ..mine where not rotton but I did have a slight break on the crimp connection

for glow plugs measure the resistance between each glow plug .this can be done with glow plugs installed as long as the bus bar is or connecting wires is removed so each glow plug can be tested individual
 
So, parked up for a week, so did all the work fix the problem? On the button folks :)
I will be changing the glow plugs later this year, but for now I want to go out and use it.
Thanks again
regards
Andy
 
You must log in or register to reply here.

Similar threads

M
high pressure fuel pump regulator possible issue after change
Replies
4
Views
709
MGT
M
M
Disco 4 - Juddering
Replies
1
Views
793
lynall
L
M
Discovery 4 2010
Replies
7
Views
1K
1988smithy
1988smithy
G
Sport Fuel Pressure Issue RRS 2016 TD6
Replies
8
Views
1K
Mark Piercy
Mark Piercy
S
Starting issue. Fuel system bleed
Replies
8
Views
982
sjr202
S
Back
Top