TD5 fuel pump

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Ruari

Active Member
Posts
281
Location
North Ayrshire
My 110 isn't starting.
I plugged my fuel pressure gauge in and its getting 20psi (just over 1 bar) as soon as the pump stops running the pressure drops to zero. I then placed the gauge inline before the filter housing same readings.
Clamp the hose on the outlet from the pump, still same readings.

Thus I'm concluding the pump is faulty. UNLESS - does the pump have a one way valve to stop fuel re-entering the tank thus keeping the pressure up?


This time I will be cutting the inspection hatch, forget draininng a 3/4 tank to drop the tank etc

Any thoughts on the subject welcome
 
when you say you plugged the gauge do you mean in the FPR instead of the sensor?... cos if you get 1 bar there the pump is certainly not delivering high pressure... you'll not get high pressure at the filter cos there's only the low pressure and the return the high pressure goes directly to the FPR
 
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The only help that I can give you is that when my fuel pump went last year it just would'nt start the next morning (no warning signs !) I cut a hatch in the floor to get at it (Def 110) and found that the filter on the bottom of the pump was full of black crap. So I cleaned it all up, put it back in and it worked for about a week and then would'nt start again. So i bought a new siemens one and it's been sound ever since !

Ps: Fecking right bastid to start again after !! even bleeding the circuit 6 times did'nt help, thought I was going to have total melt down on me starter motor until after about 40 seconds of cranking she spluttered and came to life :)
 
This has all come about as now its winter the car has died. She did the same last winter, but has been great through the summer.

I have an inline pressure gauge made with a spare FPR pipe. So I clipped it in the flow to the engine before the filter, after the filter and then (at the other end of the same pipe) as it enters the FPR. I get just over 1 bar. Drops to zero as soon as the ignition is turned off.


I now believe the gauge is faulty as the car is now running. And when it is running my gauge sites at just over 1 bar. Or I have misunderstood where to get the high pressure readings in the ciruit?.

It seems to be when ever it is left in the shed, the engine starting ok after a few days, but a night out in the cold damp it shuts down. I had a suspicion it was electrics and I did get a few faults 3120 High speed crank. 3216 Injector 4 circuit open. 3030 Airflow high fault.
Cleared the faults, engine running live data looks ok. no faults present.
 
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Although I have been running Disco & Defender TD5's for years I have never had this problem but know it is quite common. When I changed my fuel pump I did notice traces of "diesel bug" blocking the pick up filter on the pump and before fitting the new pump emptied and cleaned the tank of black sludge. Vehicle had only done 40k but had been left standing for long periods at a time. I have never experienced diesel bug before and think maybe TD5's are prone to this due to the fact that diesel heats up going through the head and returns to the tank warm and could cause ideal conditions for the bug ! I now use an additive against it ever time I fill up.

One think is for sure that any diesel engine wont run with an crap,water,air in the system, blocked filter etc.. and a TD5 needs pressure as well .

good Luck
 
I now believe the gauge is faulty as the car is now running. And when it is running my gauge sites at just over 1 bar. Or I have misunderstood where to get the high pressure readings in the ciruit?.

It seems to be when ever it is left in the shed, the engine starting ok after a few days, but a night out in the cold damp it shuts down. I had a suspicion it was electrics and I did get a few faults 3120 High speed crank. 3216 Injector 4 circuit open. 3030 Airflow high fault.
Cleared the faults, engine running live data looks ok. no faults present.

that high speed crank fault code is the only one which can explain a running issue...if the high speed crank signal is bad the car will start but might cut off when you try to rev it up

if you connected the gauge to that flexible pipe which is like te one you used for the gauge that's the return pipe and no high pressure there, the high pressure feed goes directly into the FPR, you can clip in a fitting instead of the metal connection as to be able to screw it instead of the sensor... then you'll see if there's high pressure or not, no other way.
 
if you connected the gauge to that flexible pipe which is like te one you used for the gauge that's the return pipe and no high pressure there, the high pressure feed goes directly into the FPR, you can clip in a fitting instead of the metal connection as to be able to screw it instead of the sensor... then you'll see if there's high pressure or not, no other way.

Not quite following you here.

Does Fuel come out of the filter and clips into FPR, from there it runs around the engine, back out the FPR (a screw in fitting) in to fuel cooler before returning to the filter???

I removed the pipe from the filter to the fpr an inserted my gauge inline at that point. The pipe coming out of fpr still goes to fuel cooler before returning.
 
i say again through the filter there's no high pressure feed only the low pressure and return is circulating there, the HP feed goes from the pump directly to FPR in the port which is oposed to the regulator, the other one which goes to the cooler is the return and if it's 15P engine there's another flexible return from the injectors, on 10P the spill return is through the head...see the attachments, i coloured the only high pressure feeds with red, the easyest way to measure high pressure is in the port where the sensor is
 

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    FPR HP.jpg
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  • Fuel feed.jpg
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So does the low pressure go through the filter and then return into the pump for the HP pump? That makes sense at the filter.

I need to check my gauge on something else. I did connect it at the inlet to the fpr for HP. But I only get 1bar and the car is running.
 
I don't quite understand all this fuel pressure gauge malarky because when the inevitable fuel pressure regulator leaks and I have seen them ****sssing out diesel as people have re-fitted with the wrong gasket and this never stop's the engine starting and running fine !!!!!!!!! :confused:
 
So does the low pressure go through the filter and then return into the pump for the HP pump? That makes sense at the filter.

I need to check my gauge on something else. I did connect it at the inlet to the fpr for HP. But I only get 1bar and the car is running.

the car might run at idle and low revs even with 0.5 bar there but will die under load
 
I don't quite understand all this fuel pressure gauge malarky because when the inevitable fuel pressure regulator leaks and I have seen them ****sssing out diesel as people have re-fitted with the wrong gasket and this never stop's the engine starting and running fine !!!!!!!!! :confused:
the gauge is to see if the pump delivers the HP or not cos if it does the FPR will leak always on the return so in the feed you must see the pump's pressure if it's proper or not cos it's quite common that only the HP fails so you'll hear the pump running on LP but the engine will missfire;)
 
Thanks Sierrafery

Its a bit of a hassle to strips my mates disco to plug in the fuel gauge. So I may just swap the fuel pump.

Just our of interest, what is the wee pipe on the side of the FPR, is it a spill pipe or should it be connected to a vacuum? FOUND THE ANSWER FPR WORKS ON ATMOSPHERIC PRESSURE, SO NO NEED FOR VACUUM PIPE
 
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FIred the engine up last night, took a few turns, enough to raise an eyebrow but not enough to think she won't start. 1 bar of pressure.

Cut the hatch, easyenough to cut a hole but a bit of barsteward to remove the section of floor support. Anyway all done, time to make a cover.

Replacement pump fitted, engine fired up straight away and is at 4 bar of pressure.

So an engine with 1 bar of fuel pressure does run. But down on power.
Hopefully that is the end of my woes.....
 
Glad you got it sorted ;)
Mine would'nt run or fire even though the fuel pump was running (could hear it) and was a right tw@t to start after but has been sweet as a nut ever since :)
 
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