159 V6 Fuel Pump

[Stu159]

Hi all,

has anyone else had issues with fuel clogging up on long drives on their 159 V6? It seems fine once the car has cooled for a while and then driven again though. In each case there has been ample fuel in my tank and I never let it go lower than 1/4 full, before filling it. The car has never had anything but 98 ron in it and I've owned it since new. A friendly AROCA Canberra member gave me this report from his mechanic, as he'd had the same issue with his car. I was wondering if anyone had sorted a solution to the problem?
AROCA member report
"The exact cause isn't clear, but the filter in the combined pump-filter-fuel gauge unit has become clogged, causing the engine to stumble after a couple of hours of driving. With prolonged operation the pump sucks up enough stuff to cover the pump opening. 

My mechanic saw that on the base of the tank, where the pump sits, pushed down by springs in the pump's chassis, there were rubbing marks on the surface of the tank. It seems that the pump is moving, possibly creating the particles that get into the filter." (end of report)

It's happened to me on x 3 occasions now, but doesn't always happen. Last time (before yesterday) was on a Sydney-Canberra trip. I stopped for x 15 minutes, then drove it the rest of the way there, no problem. I put a fuel cleanser into the tank on arrival in Canberra and it has been fine ever since. No issues on the return trip home at all. The same yesterday, I stopped for x 10 minutes, then started it and drive to a service station. Filled it up, put a cleanser in it, then drove it home. I had been on a long drive yesterday, before it happened

Thankyou. Any reports or solutions would be greatly appreciated

[JPetrarca]

I also have a V6 and never experienced such a problem. I use 95 fuel.


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[Colin Edwards]

We had a V6 for about 4 years and did around 100,000 klm without any fuel issues.  I did run Liqui Moly injector cleaner through it around every 7,500klm though. 
The cleanliness and handling of the fuel may be the issue.  I've been told the filter in the tank is integral to the pump and so is "for the life of the vehicle" - should never need replacing!?!

[bazzbazz]

Ok, The problem is one of 3 things -

1/ Most likely the pump is just on it's way out as the motor or brushes in the pump are worn. The longer it continuously runs the more trouble it has coping. I have come across this issue before in both 156 & 159 cars.
The problem will only get worse over time to the point where occasionally the car won't start.

2/ It can also be caused by the contacts of the Pump Relay being burnt/worn, again resulting in random failures, and when the car has cooled down again, so do the burnt contacts. It can be a bit of a "chicken and egg" situation too, as the worn pump will put a bigger load on the relay contacts causing them to burn. So if you need to replace the pump, ALWAYS replace the relay too.

3/ The Fuel Cutoff Impact Switch under the front passenger seat. This switch is designed to open circuit in the case of a high impact or roll over accident, and when doing so removes the earth from the pump circuit.
Sometimes these can get a little dicky/sensitive with old age, simply give the big rubber button under the passenger seat a press to make sure the mechanism is properly seated.

My suggested course of action would be to -
A/ Reset the Cut Off Switch
B/ Replace the Fuel Pump Relay
C/ And if this does not rid you of this problem simply bit the bullet and replace the in tank pump, I have never known of the built in filter in the pump getting blocked to the point where it causes the problem, (not saying it can't happen, but never known of it myself) but whether it is the filter or just a tired pump, replacing it will solve the issues.

[Stu159]

thanks yet again to everyone for their feedback and especially you Bazz. Fantastic response, as always! Seems to me like it might be option 2, that you've noted Bazz. Must be something along those lines when you consider I can start it again after x 10 minutes and it runs perfectly. It still idles by the way, just starts to falter under load when accelerating. It doesn't actually cut out. It has only happened when the car is very hot also, after several hours driving.

For the record my car is just under 110,000k's.

I think I'll try the Liqui Moly idea from now on also Colin. I could feel the difference when I drove it again today

Thanks again everyone, for the feedback, much appreciated

Stu

[Mick A]

I would like to add, while I have seen this happen before and it has been a buildup of sludge in the bottom of the fuel tank, the last car we had in for the same problem, perfect idle but no power under load and a hesitation.

Did the obvious thing and looked at the in tank pump and checked the tank for buildup of sludge, and found nothing that suggested a problem in the tank. The fuel pressure was correct, the car idled and revved in the workshop fine, but taking it for a drive, the car had no power under acceleration.

The problem ended up being the high pressure pump that is driven off the camshaft that supplies the extremely high pressure to the fuel rail for the injectors. The in-tank pump only supplies fuel flow to the high pressure pump, that is it's only purpose, to bring it from the tank to that pump.

I would suggest using diagnostics and looking at the fuel pressure under load on the high pressure pump side.

Hope the information is useful and provides some food for thought.

Cheers

Mick.

[bazzbazz]

Maybe a little clarification is needed here, as the only reference to any actual problem STU makes is -

"It seems fine once the car has cooled for a while and then driven again though."

So we should as, "what are the actual symptoms". I took it as meaning that the car stopped and wouldn't start again till it had been allowed to sit for a while, while Mick has taken it as lacking power and it needed to sit a while then power returned.

So STU, which is it? One or the other, both, or neither?   

[Citroënbender]

Any warning lights or error messages displaying?

[Stu159]

Hi Bazz, Mick & 'Bender,

Sounds like Mick is on the money. The car has never actually cut out. It is exactly as Mick has described it. Idles, revs when stationary, then falters under load.
In each case I've stopped (no choice anyway) and once the car has cooled, it has run fine. As I've noted prior though, it has only sat for 10-15 minutes each time and it has been travelling for hours in the lead in, so we're talking minimal cooling really. I might add, that in between times it has happened, the car has still be driven long distances, like Sydney - Taree - Sydney in x 24 hours and it hasn't happened at all.

I've actually relayed that info you gave me to my AROCA Canberra contact in between, Bazz and he has reported that he thinks it's definitely fuel. His car is
identical to mine, 2006, V6, 6 speed. Another member from the ACT has had the same issue. Here was his response to my email,

"What I can say is that new pumps have not staved off the problem for very long, and that my mechanic reckoned that he could see evidence of the pump moving relative to the base of tank and that the tank wasn't very clean inside despite a life of 98 Octane fuels. Some of the stuff in there looked a bit like the tank lining. A suggestion was that with the hotter temperatures that we get in South Africa and Australia the tank expands more causing the movement. One of the Canberra club members took her tank out and cleaned it - handy to have worked in the trade and live on a farm so you have those bits and pieces.

The theory that I'm happiest with is that there's gunk in the tank that over a long drive gets sucked up to the fuel pump pick up. By turning the engine off entropy takes over an the gunk disperses. The longer you leave it the better it is. Putting more fuel in mixes things up much more quickly." End of response

I will report back once I've had my mechanic look at it

P.S. no abnormal signs on dash "Bender"

thanks again everyone

[bazzbazz]

In that case get your Mech to check the diagnostics and compare the "Fuel Pressure (Calculated)" & "Fuel Pressure (Measured)".
Basically it's what the engine wants, and what the engine is getting.

It most likely will be the Fuel Pressure Regulator or the High Pressure Fuel Pump.

[AlfaArt]

I've also had a similar problem with my 2006 v6 manual 159. Both times car suddenly lost power after some hours of motorway cruising. Both times there was about 1/8 tank left or about 10 litres. First time was about a year ago on Hume Hwy. Car lost power, wouldn't even idle but restarted after 15 minutes but lost power again a few kays down the road. Had to get NRMA out who put 10 litres of fuel in. Car then started and I drove to nearest servo where I filled up and had no further problems. Second time was last Sunday on M1 north of Brisbane, where at 1/8 tank left, the car again lost power and I had to pull over which was not a nice thing on M1 with traffic whizzing by at 110! Car idled fine this time but no power at all. Had to call RACQ who towed me to the servo where I filled up and again no further problems. My plan is to get a replacement pump from UK at about $1000 and change relay. What do you think?

[JPetrarca]

I have a 2006 V6 Q4 and travel 250kms every couple of weeks and haven't encountered any fuel pump issues. I'm n Victoria.


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