Motion Potion Troubles

[Slojo]

Hi
I'm at a dead end here with this problem. I have a 2000 fly by wire 2.5 Bongo which whenever I use it for journeys where the engine gets hot, I have real trouble starting again, especially if the fuel tank is around a quarter full. Sometimes if I get stuck in traffic the engine will just peter out causing all sorts chaos. I have changed all the fuel hoses and fitted proper fuel hose clips, checked all the filters, I am going to install a non-return valve tomorrow to try. Any other ideas will be greatly appreciated, apart from this problem the engine runs great, no smoke, pulls like a Trojan, uses no oil or water. HELP!

[the laird]

When it happens have you tried to remove the fuel filler cap to listen and see if you hear a thump or vacuum release ? May be a blocked breather ?

[Northern Bongolow]

i would first try the breather system on the diesel tank. they can get blocked. try running with the cap off the tank as the tank can air lock and make it hard to keep running if a vac has built up in the tank. in the link there are breathers that can get blocked with over keen undersealing and the one up to the filler neck can get filled with crud.

http://lushprojects.com/bongopartsmk2/c ... mgno=.html.


beaten by the laird. .

[The Great Pretender]

My typing is too slow, no replies when I started………….


Sorry to hear about your problem, I have no knowledge of the fly by wire IP so will consider it as the same as the wired one.
Your thinking of fitting a non return valve suggests you think you have a vacuum in the tank, the tank filter blocked and or the low pressure side of the pump seal is drawing in air. You could run with the tank cap loose. Force low pressure air back through the fuel line to clear the tank filter, if that fails fit a lift pump to aid the IP.
Others on here maybe able to provide more specific information.
Good luck and welcome to the forum.

[Slojo]

Hi guys what a response I have already been down this road, I have had the tank out to check it was clean, checked all the vent pipes and valves. The only thing I found in the tank was two braided cables about 6" long?

[The Great Pretender]

Do you understand how the IP draws its fuel?

[Slojo]

No not really, some pumps have a vane or gear set up that pulls the fuel from the tank. I was wondering if the fuel was getting too hot when it was getting low, I know that VW and Merc Sprinters fitted a fuel cooler.

[The Great Pretender]

The pump sucks fuel into the low pressure side. At low speed it can if the front seal is faulty draw air in (the lower the fuel level the harder it works) hope that makes sense?
Fitting a cheap lift pump instead of a one way valve may show you where the cause of your problem is.

[Slojo]

Hi
Thanks this is giving me a direction to go. I have a 12v lift pump I'll try that. Do you know how easy a seal would be to fit?

[teenmal]

HI, does the injector pump have a fuel leak/drip ?.

[the laird]

Not beaten by me just assisted as we all are
Maybe should've put aided

[Slojo]

Hi All
No the engine is bone dry in all aspects. I have contacted the dealer who I brought it from I think that they should put it right we'll see eh.

[windywatson]

Hi,

I have V6 Petrol and have experienced exactly the same symptoms as you. It has been difficult to track down as it has only been happening when "very" hot.
The thing is this, it may not be anything to do with the fuel side of the system, well the petrol side. My van is LPG converted and has displayed these symptoms whilst on LPG so I switched to petrol thinking I had a problem with the LPG system only to have exactly the same problem on petrol.
My van spends winters on a SORN so currently not having this problem looked at. Will have it investigated when it goes for its pre season service.
So please keep us posted with your findings as it will benefit other members such as my self solve same or similar faults.

I have previously posted about these symptoms myself and had done the running with the filler loose etc to no avail such as yourself.

Cheers

[Slojo]

Hi Windy
I actually thought I cured my problem once when I changed the sensor for the scavenger fan. I checked the original sensor with a heat gun, temp gauge and a Ohm meter, the sensor closed at 53C however I still bought a new sensor and this closed at a lot earlier and it did help with the problem a lot. When I stop the engine the fan starts up after a little while, which it never did before.

[windywatson]

Sounds good advice, never heard the scavenger fan running on mine. So that could be contributing to the problem. Need to do the same I think. Where did you get your replacement from & was it expensive?

cheers