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Fuel tank leak/hunting idle and low power

Posted: 27 Sep 2022, 17:33
by mshaw1980
Hello

After 7 years of having my van I am still killing fuel pumps (subaru conversion). The tank is less than 5 years old from brickwerks. This time I have installed a pre fuel filter as well as a post pump filter. Have also fitted the bosch pump in the factory position using brickwerks mount. Only problem is that installing a pre pump filter means that the pump is not gravity fed. Then again, I cant see how the pump on these was ever gravity fed as the factory pump mount position is above the fuel tank outlet.
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Also having another issue. My van had less than a quarter of a tank of petrol, just put £50 in which equates to around 30 litres of fuel and it is leaking out the top of the tank. No way is there 50 litres in it so why is it leaking??? Could this issue be related to why my van keeps killing pumps as in something wrong with the expansion tank system. Would really appreciate some help as at this moment getting sick of the thing. Cheers

Re: Fuel tank leak/hunting idle and low power

Posted: 27 Sep 2022, 19:22
by multisi
What is the pipe with the green printing on it for.

Re: Fuel tank leak/hunting idle and low power

Posted: 27 Sep 2022, 19:49
by Oldiebut goodie
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Webasto heater fuel line.

(Silencer should be rotated 90 degrees - so that the drain hole is on the bottom.)

Re: Fuel tank leak/hunting idle and low power

Posted: 27 Sep 2022, 19:53
by mshaw1980
I have disconnected the webasto line for now to see if that helped with pump cavitation. Oldie, can you take the webasto feed from the fuel return side instead?

Re: Fuel tank leak/hunting idle and low power

Posted: 28 Sep 2022, 08:51
by Oldiebut goodie
The tee shouldn't cause any problem with the fuel pump. You could try using the return line but I don't know how deep into the fuel the return goes so may not work.
Another point to look for when using the return is whether there is a non-return valve in the tank - people have been trying to use the return on T5 and T6 vans and have found out that they have a non-return valve so you are only able to use the fuel back to the engine!

Re: Fuel tank leak/hunting idle and low power

Posted: 29 Sep 2022, 06:37
by Aidan
do you have a fuel injection tank ? with the 12mm outlet ?
if you do then you don't need a prefilter to protect the pump (it is built in to tank) and if you have a non injection tank with the smaller outlet then using the big filter designed for pressurized side of pump wouldn't be my choice of filter as you are further restricting what is already a restricted feed
Sounds like you ned to drop the tank and see what is wrong with the breathers and level sender and if it's not the fi tank then replace it with the fi version while you are at it
 

Re: Fuel tank leak/hunting idle and low power

Posted: 29 Sep 2022, 12:02
by slowcoach
Maybe get a fuel pressure gauge to check it's not over pressurised all the time, making the pump strain- A failed fuel pressure regulator would do that.

My webasto takes the t off just after the tank outlet (fi tank on a Subaru motor), so don't think that's your problem.

Re: Fuel tank leak/hunting idle and low power

Posted: 29 Sep 2022, 14:00
by Stesaw
That dangling wire makes me wince a bit. :lol:

Re: Fuel tank leak/hunting idle and low power

Posted: 29 Sep 2022, 14:29
by multisi
Only needs a short wire earthed onto the chassis rail.

Re: Fuel tank leak/hunting idle and low power

Posted: 29 Sep 2022, 21:25
by mshaw1980
The dangling wire was rectified 😂. I fed a wire directly to the negative terminal on the battery to see if that helped with burning out fuel pumps.
I ran the van today and could feel the feed hose to the fuel rail pulsing but the tank return line could just feel a steady stream of fuel passing. Good job I did this actually as the hose coming from the fuel filter to the fuel rail was cracked all over, however there were no leaks but potential fire risk.
Ok so I knew from what Aidan said ( I do have the fuel injection tank with 12mm outlet)there is a strainer in the fuel tank to protect the pump but something must be causing them to die so frequently.
What about my issue where the tank overflowed after I put about 30 litres of fuel in even though I had less than 10 litres in the tank. Could the expansion tank system be causing problems for the pump in terms of it having to suck harder??

Re: Fuel tank leak/hunting idle and low power

Posted: 13 Oct 2022, 20:14
by mshaw1980
So just an update on my fuel pump issues. I ran the engine and the fuel pump started squealing and it was then I noticed that the fuel hose from the pump to the fuel rail had swollen to nearly twice its diameter! Thank God it didnt burst. Removed the fuel pressure regulator and a lot of fuel burst out and the feed hose returned to its original size. Fuel pressure regulator must be nearly closed so the pump has been trying to pump litres of fuel per min through the equivalent of a straw. No wonder it was getting hot. Thanks for all your suggestions 😃

Re: Fuel tank leak/hunting idle and low power

Posted: 13 Oct 2022, 20:56
by Smiffo
mshaw1980 wrote: 27 Sep 2022, 17:33
 Would really appreciate some help as at this moment getting sick of the thing. Cheers

A new found love blooming!?  :D

Re: Fuel tank leak/hunting idle and low power

Posted: 14 Oct 2022, 07:37
by mshaw1980
We'll see when the new fuel pressure regulator is fitted 😂

Re: Fuel tank leak/hunting idle and low power

Posted: 14 Oct 2022, 07:51
by mshaw1980
We'll see when the new fuel pressure regulator is fitted 😂