Bongo stalls on long journeys

[Chris may]

Hello and help!
We have a 10 year old (R Reg) Bongo Diesel. Over the last couple of months the Bongo has developed a severe problem where after about 1 - 11/2 hours hard driving (usually motorways) any reduction in the throttle (to slow down) causes the Bongo to lose power and stall. Once stalled the engine has difficulty starting although it gets better for leaving it for 10 minutes. The local garage has brought in specialist diesel technicians but the problem persists although not quite as bad?!
The garage has:
1 checked for air in the system by using a see though pipe to monitor the flow of fuel;
2 changed the banjo filter in the diesel pump;
3 capped off the Exhausted recirculation system; and
4 replaced the battery.

The last 2 efforts (capping the exhaust recirculation and replacing the battery) has helped but on our journey this weekend after about 1 ½ hours of driving the engine coughs and loses power and generally stalls.

Around town the Bongo drives perfectly well and its problems are only on long journeys. The first sign of this trouble seemed about a year ago to be difficulty in starting after the engine had been switched off during long journeys (for refuelling for instance) It has steadily got worse.

We are due to take the Bongo to France a week on Thursday and we are getting desperate.
Any help/ideas will be gratefully received
Chris

[scanner]

Have you checked that the fuel tank breather isn't blocked?

If it is, as the fuel is used up a vacuum forms in the tank and it's harder and harder for the pump to suck the fuel through.

Next time it stalls take the fuel cap off and see if there is an almighty "plomph" of air.

[Steve L]

The only other thing I can think of is the stop solenoid playing up, but the symptoms would point, as Scanner says to a blockage in the breather system of the fuel supply.

[daveblueozzie]

My brothers bongo had similar problems until Monday this week when a new fuel pump was fitted, all ok now , he uses the bongo everyday for his work, its his work vehicle.

[Marcus Beechcroft]

Hello. I've noticed a slight noise on taking off the filler cap. Can you tell me where the fuel breather is?

[missfixit70]

http://www.lushprojects.com/bongopartsm ... o=.html#20 breather pipe (42260) comes off the top of the sender unit cover plate & goes up to the filler pipe (z)

[dandywarhol]

A slight shhhhhhhhhhh is normal, fuel is returned to the tank causing a slight pressurisation.

[scanner]

A slight shhhhhhhhhhh is normal, fuel is returned to the tank causing a slight pressurisation.

How? I've never understood this.

Unless more is returned than is drawn out and that's hardly the case with a Bongo is it?

Surely there can only ever be a vacuum?

[francophile1947]

But if there was a vacuum, wouldn't the fuel eventually stop coming through I always thought the filler caps had a vent hole

[scanner]

But if there was a vacuum, wouldn't the fuel eventually stop coming through

YES! that's why the engine stalls after running for a while, the vacuum is then stronger than the suck of the pump.

I always thought the filler caps had a vent hole

Not always in the cap, sometimes a separate pipe that vents outside the tank.

If that gets blocked, the air can't get in and the vacuum builds up. Sometimes if it is only partially blocked there isn't a problem until you do a very long journey without any stops to let the vacuum drop a little.

I saw a Vauxhall Viva once where the tank had imploded because of the vacuum that built up.

Here
http://forum.landrovernet.com/showthread.php?t=20461
is someone who has had it happen to a Land Rover.

[francophile1947]

Hmmm, perhaps I'd better check my cap - don't fancy a flat tank

[Doone]

I agree with Scanners suggestions. The first thing I'd try is changing the filler cap.

[Eat Aunt]

But if there was a vacuum, wouldn't the fuel eventually stop coming through

YES! that's why the engine stalls after running for a while, the vacuum is then stronger than the suck of the pump.

I always thought the filler caps had a vent hole

Not always in the cap, sometimes a separate pipe that vents outside the tank.

If that gets blocked, the air can't get in and the vacuum builds up. Sometimes if it is only partially blocked there isn't a problem until you do a very long journey without any stops to let the vacuum drop a little.

I saw a Vauxhall Viva once where the tank had imploded because of the vacuum that built up.

Here
http://forum.landrovernet.com/showthread.php?t=20461
is someone who has had it happen to a Land Rover.

Yes same happened to me with my dear old Vauxhall Bedford CF 2.3 petrol Campervan.... blocked filler cap..... regular breakdowns with fuel starvation, until one day the tank imploded aaaaarrrrrrrrrgggg.

Well worth trying a new filler cap in your Bongo Chris ...or... borrow someone elses filler cap for a test run maybe...


p.s. does anyone want to but a 1983 Bedford CF Coachbuilt ( Ci Motorhomes of Poole) Campervan . 49,000 genuine miles

[scanner]

Is that the one with the 2 gallon petrol tank?

[Eat Aunt]