Fuel filter losing it's prime

Technical questions and answers about the Mazda Bongo

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Jacqui

Fuel filter losing it's prime

Post by Jacqui » Tue Dec 28, 2010 11:30 am

Does anyone have experience of the following? Picture the scene, a snowbound filling station on the NE coast & I'm late for work;
I started to put some diesel in the Bongo and the the pump stopped (at 63p) because the tank was empty,
I move onto the next pump and filled with about £20 more diesel.
Drove to work no problem but at the end of my shift the Bongo wouldn't start, felt exactly like no fuel.
Eventually looked at the fuel filter, tried the priming plunger atop of the filter and found barely any resistance when pressed, after much spinnining of the engine tried the plunger again and I could feel the resistance build up, tried to start again & the Bongo sprung into life.
Now I have the same problem almost every time the car has been stood for a few hours ie. the fuel filter is losing it's content.
The filter is only 6 months old. I'm going to replace it.
still can't imagine why a contaminated filter would cause the filter bowl to empty after the car stops for a while though?
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daveblueozzie
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Re: Fuel filter losing it's prime

Post by daveblueozzie » Tue Dec 28, 2010 11:38 am

Possibility of the last dregs of fuel from the garage being contaminated with crap, new filter wont do any harm and don't forget to clean the banjo filter as well, this collects the finer bits of crud that the main filter misses.
Lost without my Bongo.
Jacqui

Re: Fuel filter losing it's prime

Post by Jacqui » Tue Dec 28, 2010 11:46 am

where is the banjo filter?
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T9sus4
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Re: Fuel filter losing it's prime

Post by T9sus4 » Tue Dec 28, 2010 12:09 pm

Jacqui wrote:where is the banjo filter?
Between the guitar filter and the ukulele filter. :wink:

(Try http://www.igmaynard.co.uk/bongo/forum/ ... mit=Search and you will find many threads explaining everything you never knew you needed to know about the banjo filter)
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rita
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Re: Fuel filter losing it's prime

Post by rita » Tue Dec 28, 2010 12:43 pm

Hi Jacqui,

It sounds like the fuel is syphoning back into the tank,it might be worthwhile looking at the non return valve.

Cheers..
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Re: Fuel filter losing it's prime

Post by daveblueozzie » Tue Dec 28, 2010 12:45 pm

Lost without my Bongo.
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chipvan
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Re: Fuel filter losing it's prime

Post by chipvan » Tue Dec 28, 2010 10:07 pm

put a clear winow in the fuel line in and out of pump,bet its air geting in..somewhere.

if you cant fint the air ingress fitting a tiger loop will cure it ,but last resort!
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The Great Pretender
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Re: Fuel filter losing it's prime

Post by The Great Pretender » Tue Dec 28, 2010 11:50 pm

daveblueozzie wrote:Possibility of the last dregs of fuel from the garage being contaminated with crap, new filter wont do any harm and don't forget to clean the banjo filter as well, this collects the finer bits of crud that the main filter misses.

:shock: Are you sure it's finer Dave? As it is so small if it was stopping particles finer than the filter it would't last 5 min. :wink:
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Re: Fuel filter losing it's prime

Post by dandywarhol » Wed Dec 29, 2010 2:00 am

Yep - it's there to collect the paper fibres from a new filter.
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The Great Pretender
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Re: Fuel filter losing it's prime

Post by The Great Pretender » Wed Dec 29, 2010 2:15 am

dandywarhol wrote:Yep - it's there to collect the paper fibres from a new filter.
Yep it is finer or it picks up what the filter contaminates the system with?
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chipvan
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Re: Fuel filter losing it's prime

Post by chipvan » Fri Dec 31, 2010 11:31 am

tgp,did you not remove your banjo filter??
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Re: Fuel filter losing it's prime

Post by chipvan » Fri Dec 31, 2010 11:42 am

if the banjo is finer than main filter that would block up so quickly!!,if you hold up banjo filter you can see holes through it.dont think if you had a 5 or 10 micron filter you would see any holes through??

I would say that the banjo is about 100 micron,or maybe 50 micron ??
ronhud

Re: Fuel filter losing it's prime

Post by ronhud » Fri Dec 31, 2010 12:06 pm

I have had occasions when the engine would'nt start and removing and cleaning the banjo filter fixed it. So something had reached the banjo filter but not been able to go through it. Not quite sure what that proves tho!!
Ron
Jacqui

Re: Fuel filter losing it's prime

Post by Jacqui » Fri Dec 31, 2010 12:18 pm

Thanks for the advice one & all.
I took the filter out and emptied the contents into a clean jar, the liquid was milky (emulsified) and settled out with a lot of particulate in the bottom layer which looked like & felt like wax/grease.
It would seem that the last dregs from the filling station were contaminated.
Replaced filter, checked banjo filter (once I returned from A&E after splitting both of my sides laughing at the "guitar / ukelele" gag)
nothing in the banjo.
Bunged half a litre of petrol in in the hope of dispersing any wax that may be still in there.
Couldn't locate the non-return valve, interested to find it if anyone could point it out.
Engine started and has continued to start (for now).
Fingers crossed, it is sorted.
Cheers again.
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The Great Pretender
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Re: Fuel filter losing it's prime

Post by The Great Pretender » Fri Dec 31, 2010 7:10 pm

chipvan wrote:tgp,did you not remove your banjo filter??

Yep................ :wink:
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