D5 (D5244T to 2005) Water in my Diesel Tank ...

[chopper_harris]

Hey Guys

It's nice to be back, after the down time.

Following a recent trip to the Irish Republic, the V70 started running very poorly.
We had refuelled about 80 miles out of Dublin, at a hick town garage (no offence intended). We were almost out, so there was no option.

We made it home, and dropping the fuel filter showed lots of water/diesel emulsion - no alternative but for a drain down and wash out.

Removing the LHS sender and RHS sender/pump were not a real issue, and with the assistance of a spotty youth (#1 son) you can get an arm inside the tank to really wipe it down with a little TFR and clean cloth.

Top tip - use a vacuum cleaner to suck up all the crap which accumulates around the tank locking rings - before it ends up in the tank.

So far so good, but I got something wrong during the refit. I added 4 gallons to a bone dry tank, ignition on for 20 seconds and she started 2nd turn.

Went for a run, and she died after about 15 miles. Removing the filter confirmed it was bone dry.
Ignition on, rock the car side-side to refill the RHS tank, and we are good to go.


So, either I have kinked the cross tank feed, or knackered the mechanism in some other way.

Can anyone help with a schematic, or pointer to a detailed description of how fuel is pulled from left to right ?
There is no pump on the LHS - I recall that the cross pipe is clipped along the pump body and terminates in a U shaped plastic part inside the pump frame.

How the *** does the fuel get from left to right ?
I've searched the previous petrol/diesel posts, but am non the wiser.


Suggestions on a postcard, please.


I have taken lots of detailed photos' which I'll post up in a new thread over the next couple of days.

Regards, as always

Chopper

[Laney760]

This may be of absolutely no use to you, but just in case it is, somebody on a Volvo forum in the US who had water in their fuel in their V70 (but cannot ascertain whether they are petrol or diesel) and subsequent problems after clearing out - the thread refers to a 'balancing sensor' in the right hand sender or the pump

[Bernard333]

I have similar problem with 2003 V70 D5 , car stops dead when tank gets to 70% showing on fuel gauge , this has been going on a long time and is one of a number of problems , a new fuel pump was fitted and I know this was necessary because I have the old one sitting in front of me and I know for sure its knackered but now I think that the cross feed pipe not being connected or blocked is whats causing the problem and this must have happened at around the same time as the electric fuel pump conked out but because we thought we had got one problem we couldnt possibly have two . We set off on holiday with the new pump installed and then car stopped dead middle of nowhere in France cost 160 Euros for a breakdown truck to deliver diesel and the experienced mechanic who attended and lucky for me spoke some english had never seen this happen , sure enough put in 25L of deisel to show competely full and the car starts up again . I will now follow what you have done and take the sender units out and check the pipework . Incidentally I am also in Ireland and now I know why diesel costs 20p a litre less than england !

[Clan]

The fuel pipe returning excess fuel from the engine passes through the bottom left part of the tank and has a venturi device which a jet of fuel squirts through causing a partial vacuum , this picks up fuel from the left side and carries it on down the pipe to be deposited in the swirl pot around the pump in the right hand side keeping it topped up .. If this venturi was blocked there would be other major problems with pipes at the front blowing off due to excessive pressure .
I would think your in-tank pump would have been damaged by the water . A New pump/assembly should have cured it . ( Volvo dont sell the pump on its own )

[Bernard333]

I can understand a fuel pump could be damaged by water but why in my case does the car just stop dead when the fuel gauge shows approx 70% full , this is after replacing the fuel pump and fuel filter, if it were intermittant failure then it wouldnt do it in the same situation each time . The only clue I can give is that I couldnt get hold of a Volvo fuel pump and it was replaced with a second hand Denso pump costing £10 which fits perfectly in the bosch harness etc and was also measured to give 2 bar pressure output which is what the volvo/bosch original is rated at . My problem is getting to stay in one place long enough to get an expert to look at it , its not keeping me off the road but want to get it sorted as my maximum range at the moment is about 250 miles then I know I have to fill the tank full .

[Clan]

I had this problem once using a petrol tank pump to replace a faulty D5 tank pump which looked right and pumped fuel but it never worked properly , Fitted a new volvo unit and all was ok . There are all sorts of pressures and flow rates for these in tank pumps for different cars ...
maybe the flow rate is all wrong . Your symptoms suggest the main pump is being starved .
Have you got plenty of volume of fuel coming out the main pump feed pipe at the front when ignition is turned on? and is it 2 bar up the front ?

[chopper_harris]

Clan

Is there a simple test routine I could step through to exercise the LHS pickup.

There is not enough slack in the link pipe to have the LHS pickup in-situ, whilst observing the output in the swirl pot.

Rgds

[Bernard333]

yes theres plenty of fuel coming out the pipe entering the low pressure mechanical pump , the pressure was measured by a mechanic who I have some trust in , he was recommended by the local main dealer when they couldnt look at the car . I am open minded to the possibility that the Denso pump just isnt right wrt flow rates or something similar but when we compared the Bosch and the Denso side by side you would think they were made in the same factory , they look identical , the Denso pump came out of a 3L diesel Toyota . The car runs great until you get near the critical fuel level , its been going on so long that I am now on a mission to understand the problem , its more driving me mad that I cant understand whats happening than the actual inconvenience . I am also assuming that the electric fuel pump just has 12V or zero applied and has no voltage control to regulate the output pressure as its controlled by an on/off type relay ? The other problem is the 360 Euros I was quoted for an original replacement complete with sender unit ( parts supply only ) , had it been about half that price would have had bitten the bullet by now .

[Bernard333]

Chopper Harris , I am looking forward to seeing the photos how you resolve this in hoping it gives me some clues , the Haynes manual just gives some very basic information how to remove and refit the fuel pump and nothing wrt possible faults within the tank and pipework

[Clan]

I can only assume that there isnt enough flow/pressure to work the venturi device in the left side of the tank and draw that fuel over to the swirl pot when level gets low . I can see no alternative to getting a new assembly . I had to in the end ..
up to 2005 model years The tank pump works for about 12 seconds when you turn the ignition on to prime the system and also when cranking , once the engine starts the tank pump cuts off relying on the powerful suction pump in the main mechanical pump to pump the fuel around the system , which indicates that your venturi device may not be working , is it laying on the bottom of the left side of the fuel tank as it should maybe the unlet to it is blocked with debris ?

The 2005 onwards system has a cheaper main mechanical pump which cant "suck" so the tank pump runs all the time the engine is running so it is more critical ..