There is only 1 pump but it is a 2 stage system:
The two stage pump comprises a high and a low pressure stage. The low pressure stage draws fuel from the swirl
pot through the filter. The low pressure stage pumps fluid at a pressure of 0.75 bar (10.9 lbf.in 2 ) and a flow of 30 litres/
hour (8 US Gallons/hour) to the fuel filter. A proportion of the fuel from the low pressure stage also passes, via a
restrictor, through a jet pump which keeps fuel circulating in the swirl pot. The high pressure stage draws the low
pressure fuel from the fuel filter and pressurises it to a pressure of 4.0 bar (58 lbf.in 2 ). The pressurised fuel is then
passed from the pump to the injectors at a flow of 180 litres/hour (47.6 US Gallons/hour). A fuel pressure regulator is
located at the rear of the engine and ensures that the delivery pressure remains at 4.0 bar (58 lbf.in 2 ) by controlling
the amount of fuel returning to the fuel tank.
The fuel pump has a maximum current draw of 15 Amps at 12.5 V and is protected by a 20 Amp fuse in the engine
compartment fusebox.
I had a fuel pump failure some years ago & the vehicle would not even start, let alone idle. It needs the fuel at 4.0 bar to force through the injectors, even at idle.
+ 2016 D4 TDV6
Hi Ean,
Like the way you think, I have checked the fuel lines now against my stepsons D2, they look to be the same, plus I'm not sure that I would be able to get it to run, I did do around 15 to 20 klms after the head rebuild, I'm sort of ruling this out unless someone can advise me differently.
Cheers Marty
Hi Rob,
I don't think the head I installed had one, I certainly didn't fit one. A few of the heads I have done the fine mesh has already been left out by previous head removalists.
Thanks for the suggestion.
Cheers Marty
Yeh I did wonder about the 15 - 20 ks drive myself , but if it makes someone think outside the box it may make them think of something that so far hasn't been mentioned.
I was more thinking if the fuel return was blocked or wrong it may effect the fuel pressure and that could be the cause.
As I said its out of left field but worth a mention.
Cheers Ean
Hi There,
Things checked today:-
Fuel filter replaced(again) system bled
Checked the routing of the fuel lines they appear to be ok
Took the MAF sensor of my Stepsons D2, nothing different
Found a pipe off a small solenoid connected to the " after turbo pipe" and a connection to the wastegate diaphragm + an electrical connection, replaced no difference.
Cleaned all the electrical connectors I disturbed during the head repacement except the one on the fuel pressure regulator. Just a bit to difficult to get to
Cleaned the MAP sensor in the inlet mainifold.
Checked there is nothing loose connection wise on the accelerator pedal, I didn't manage to get the wires off, just checked that they were on and tight.
So now I'm at a loss. The state of play now, the engine will start every time, on some occasions I can press the "go pedal" and the engine will rev something like normal but doesn't have much power. If the engine stalls whilst I am moving the vehicle, the engine will start and idle however the engine won't rev. If I now press the go pedal maybe four or five times in succession the yellow engine light starts to flash, no increase in engine revs. I can turn the engine off, turn it back on again no engine light flashing.
When I chnaged the fuel filter the fuel pump seemed to make its usual bleeding noises and then settled down to a steady hum.
Got me a bit stumped this one. Still no DTC's active at all.
Cheers Marty
RAVE shows the low side of the pump keeps the fuel filter primed and the high side feeds fuel to the FPR then the injectors.
I am wondering if the low side is supplying enough fuel for the car to idle but if the high side isn't pumping then it won't supply enough fuel to rev the engine.
It could be a case of the high side failed after your short drive . Fitting a different pump will tell but I guess you need to see if someone has 1 you can try.
The fuel then goes from the injectors, to the FPR , the fuel cooler , filter then tank so unless a fuel line in kinked or blocked between the injectors and the filter it can't be much else.
Just my view anyway
Cheers Ean
Hi Ean,
I have checked all I really can now without actually replacing some parts, my prime candidates are the throttle position sensor and the fuel pump. I'll have a chat with the guys at TRS tomorrow morning they will know what the problem is and they will have the parts.
As I have heard on so many occasions "it will be something simple" if its that simple why can't I find it that easily. Sierrafery has aligned with your thoughts, I'm also pretty well sold on the fuel pump. However some of the symptoms I have read about point me to the TPS, I'm not sure how often or common a failing point they are.
Your opinions are always valued, thank you.
Cheers Marty
Hi Marty
A couple of things to check seeing you've done recent work, make sure you did the injector lock nuts up when you checked bump clearances, and while the rocker cover is off , double check your cam timing ,and sprocket bolt tension, for what its worth , I reckon you will have a mesh filter in the head but it's hidden behind a fat o ring behind the fpr. Also I have seen what Ean was talking about re fuel lines around the wrong way and the blokes car ran fine for about 50 kilometers after he did the head .
Hi Discorevy,
Something else to do on my day off tomorrow, I know I did all five injector lock nuts up however checking won't do any harm. I did torque up the camshaft sprocket bolts up, however this does fit with some of the symptoms. The fuel lines, 50 klms..... really............., do you happen to know which pipe connector goes where? I have the one with the push button on the regulator and the one with the collar you push back on the fuel cooler, the other pipe position on the fuel cooler won't reach.
Thank you.
Cheers Marty
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