Citroen Nemo 1.4hdi 2010 turns over but doesn’t start

[Ryan9153]

Hi all really struggling with this one my car turns over but will not start. If I spray easy start in after a while she will run but you have to hold high revs. I had it on Lexia and only fault code was fuel rail pressure sensor signal fault, I tested the wiring to it and plugged in sensor to see it at 0.5v with key on, changed the sensor itself just in case. Next I took off the fuel pressure regulator and tested that all working. The hand primer all works ok, when I take the feed pipe off the back of the fuel pump it’s squirts out fuel when I pump the primer. The only thing I can think of is there is a problem with the high pressure pump itself. Which is a fortune. Any advice greatly appreciated from the forum experts. Thanks.

[GiveMeABreak]

The 1.4 HDi Nemos also have a pump / gauge module in the fuel tank as opposed to just a sender unit, so I'd want to make sure that the pump is working properly there too, also the fuel filter - when was that last changed?

Some info on the fuel circuit for you:

Key
A - Fuel tank return circuit
B - Low pressure fuel circuit (negative pressure)
C - High pressure fuel circuit

Reference	Designation	Part number in the electrical diagrams
a	Diesel injector fuel return towards fuel tank	-
1 to 4	Diesel injectors (electrohydraulic)	1131 - 1132 - 1133 - 1134
5	Fuel temperature sensor	1221
6	Manual fuel primer pump	-
7	Fuel cooler	-
8	Fuel tank	-
9	Fuel heater (electrical)	1276
10	Water bleed screw	-
11	Fuel filter + water in fuel separator	-
12	high pressure fuel pump	-
13	High pressure fuel sensor	1321
14	Fuel high pressure common injection rail	-
15	Discharge jet	-
16	Waste gate	-
17	Flow jet	-
18	Transfer pump	-
19	Fuel flow regulator	1208 or 1277
20	Pressure limiter (integral to the fuel high pressure common injection rail)	-

Special features:

• The discharge jet ( 15) permits a rapid discharge from the fuel high pressure common injection rail when there is a rapid "foot off"
• The flow jet (17) limits the supply of fuel to the transfer pump (18) at high engine speeds
• Fuel supply circuit with negative pressure : Induction by transfer pump integral to the fuel high pressure pump
• Fuel heater function incorporated in the fuel filter
• Water in diesel fuel detector (4050) (according to market)

[Ryan9153]

Hi Marc, thanks for the information, I’ve just changed the fuel filter for a Bosch one at 5he same time I did the fuel rail pressure sensor. I was told that it was only a fuel sender unit in the tank on the 1.4hdi and that the lift pump was part of the high pressure fuel pump, I will check in the take tomorrow as there seems to be no fuel unless I pump the hand primer. So is it a case of ignition on and you should hear the tank pump going?

[Ryan9153]

Another question is can I get access to this pump in the back or have I got to take the fuel tank off. Cheers bud

[Paul-R]

Surely, if there is a hand primer then there will not be an in-tank pump?

[Ryan9153]

This is what I’m finding different opinions on if there is a pump in the tank or not guess I will find out tomorrow when I strip out all the wooden floor etc.

[GiveMeABreak]

Look - I've checked parts and for a 2009 1.4 HDi Nemo and it is clearly stated gauge with pump.

Here.....

.

This one is gauge only - you can see the outlets plugged up:

All 1.4 HDi Nemos have gauge with pump.

[Paul-R]

Look - I've checked parts and for a 2009 1.4 HDi Nemo and it is clearly stated gauge with pump.

Does it equally clearly state that there is a hand pump as well?

[GiveMeABreak]

Just about all diesels I know of have a hand priming pump and yes, it's shown in the diagram I provided (6).

[Ryan9153]

Thanks guys for both your inputs, I will be taking the fuel sender unit out today to see if it has a pump, so will let you both know, at the moment I am suspecting that the transfer pump part of the high pressure pump is at fault, because as I said when I pump the hand primer fuel comes out of the inlet pipe that goes into the back of the high pressure pump. With starter pilot but a lot of it she does fire up and run and if you hold the revs high until she is warm she runs normally, but once turned off and left for a while she will not start again. Which is why I think it’s something inside the actual high pressure fuel pump.

[GiveMeABreak]

No problem, that may well be the case if you know that sufficient fuel is getting to the HP pump.

[Ryan9153]

Hi guys not had time to take the sender unit/ pump out yet as it took ages to strip all the wood out to get access to the point, but I did take off the inspection cover and look at the wiring plug. Now there are two thick wires and two thin wires sonI doubt it is just a sender unit, it has the two thick wires which are likely to power a pump, so I’m guessing it is a pump/sender unit at the moment. So hopefully now going to check for power etc when I get 5, I know the sender unit is working, turned ignition on and checked for power on the two thick wires nothing so going to find out where the pump gets power from next. Cheers guys

[Ryan9153]

Anyone got any wiring diagrams for the fuel sender unit/ pump, I.e fuse, relay etc so I can trace it.

Thanks

[Ryan9153]

Update guys so checked the fuel sender/pump and it is def only a fuel sender, also checked fuse box and no relay for fuel pump or even wiring in the fuse box for a fuel pump relay. So I do think high pressure fuel pump has a fault probably with the transfer pump inside it, what do you guys think.

[Paul-R]

Did you work out why there are four wires? Is it possible that the thicker power wires are there for other models which do have an in-tank pump? So, the wires are there but connect to nothing. At either end by the sounds of it.

Frankly I am not surprised that there is no in-tank pump as my experience, as questioned by me earlier, is that if you have an in-tank pump then there is no hand pump. Our 2001 Xsara was like that and so was our 2003 C5.