Bongo Fury

In the last few weeks my 1999 (newer design) 2.5 diesel has been turning over much more that usual before firing up. In the past it’s always started almost instantly, but now it can take a few seconds to get going and seems to be getting a bit worse with time. There’s no smoke when starting and once it’s going it runs beautifully. Starter battery is at least 4 or 5 years old.

Normally I’d take it to my local Bongo-friendly garage but I had the head, radiator, water pump, etc. replaced last year by a garage that’s much further away from me. They seemed to do a perfectly fine job of that and this issue didn’t crop up until I’d had it back for over three months, but I’m wondering if it could be a result of that repair.

Is there anything straightforward I can check myself to locate the problem? Should I take it to my local garage where I’ll have to pay to have it looked at, or should I refer back to the folks who rebuilt the engine to see if it’s anything to do with the work they did?

As ever all advice gratefully received!

Sounds very much like Glowplug problems, maybe the ones fitted weren't the best quality or maybe the supply to the glowplugs has failed either the relay or the fusible link.

Geoff—thanks for your reply above. Still struggling with this...

I'm almost certain it's not the glow plugs. I drove about 30 miles home yesterday and when I got here turned the engine off then tried to start it immediately and it still struggled—took a good few seconds of turning over before it fired up. Surely if it was glow plug related it wouldn't have any issue starting when the engine is up to temperature?

It also feels very 'bumpy' when starting and when I switch the engine off, the whole van noticeably judders as the engine fires up and shuts down.

- I took it to my local (Bongo-friendly) garage a couple of weeks ago where—Sod's law—it started for them without any issues. They told me it needed to be plugged into a diagnostic tool that they don't have, to see if there are any fault codes, so couldn't offer any more help. However I know they're mainly doing MOTs now and shying away from more complicated jobs, so I suspect they just can't be bothered with the hassle.

- spoke to the garage that replaced the head etc. earlier this year who don't have capacity to look at it right now, but when I described the problem said it sounded like a fuel pump issue. They said there's a gauze / filter in the fuel pump that can get clogged up and prevent it from working properly.

Any more bright ideas? I'm by not a mechanic but like to think I'm pretty handy and have plenty of tools at my disposal—could I investigate the fuel pump issue myself and rule it in / out? Anything else I should be checking?

Joe, have a look at this recent discussion: viewtopic.php?f=3&t=77956

Yes if its not starting when already hot then next item is fuel filters both the Banjo and even perhaps the main filter.

Brilliant, thanks folks, I shall go and investigate…

Quick update on this...

Took the banjo filter out and gave it a good clean. Here's how it looked before cleaning:



Would that level of grime be enough to cause a problem?

I also looked and looked for the breather filter mentioned in that other thread but couldn't find it and concluded it must be hidden between the fuel tank and the chassis—I removed the plastic panel under the wheel arch (plus about a kilo of baked-on grime behind it) and can see where the smaller pipe passes through the panel but just can't see or reach it on the other side. I guess it's accessible from the floor panel above the tank but of course my side conversion makes opening that impossible.

I left my fuel cap in a filling station in the Highlands some five years ago, and have been using one of those one-size-fits-all numbers since then. It's always been fine but it sounds like the original might have a valve to allow air into the tank (the replacement almost certainly does not) so have ordered a proper replacement to rule that out.

Have also ordered a new fuel filter but the one on there looks pretty new and I'm sure has been replaced fairly recently as part of an annual service. The van started fine before I cleaned out the banjo and did afterwards too, so I'll see how I get on and replace the fuel filter next.

Another update on this (really just posting now in case this is of use to anyone else in the future)...

Cleaning out the Banjo filter didn't seem to make much difference. The van was starting fine right after I'd cleaned it but after driving for a while then stopping it was struggling again to fire up. I've also noticed after driving for a while when I stop at traffic lights and the van's idling it can struggle a wee bit and the revs drop slightly—that seems to be a common symptom of a fuel tank breather valve being blocked.

So I decided to have another look for the breather pipe and filter and found it this time! Here's a picture of where it is for anyone wondering (this was taken looking from rear passenger side towards front driver's side):



You can see it in the very centre of this picture—it's actually attached to the left hand side of the fuel tank near the back rather than the chassis. The rubber hose leads around and to the top of the tank. The filter is just pushed into the end of the hose and can be pulled out easily. The hose is attached to the tank with a clip which you'll need a pair of pliers to remove, but can be done with a bit of persistence.

My filter seemed fine, I could blow and suck air through it easily. There is a valve lodged a couple of inches up the filter end of the hose which I read somewhere else is one-way. I found I could blow through from either end but it took a lot of puff and made a weird noise in both directions like a badly-played trumpet.

I put some petrol lighter fluid in the valve, gave it a good shake and blew through from the filter end with an air compressor (the direction air would have to go into the fuel tank). After I'd done that a few times it seemed a lot easier for air to travel in that direction, but there was still just as much resistance the other way.

I'll see how I get on with that over the next few days. If that hasn't made any difference replacing fuel filter is next on the list.

Really useful, thanks.

Not many know about the valves, and from memory don't think the drawings indicate the inner one way valve, let us know if it makes a difference.
I've always wondered if these getting blocked contributes to some problems blamed on the fuel pump leaking back when the engine is stopped .

I think the one-way valve is the basic floating steel ballbearing type which corrode and stick

This seems to be the correct drawing for the diesel tank:

http://www.lushprojects.com/bongopartsm ... o=.html#32

Some other threads on here discussing this issue link to a similar drawing for what I assume is the petrol version, which doesn’t have that breather pipe and is perhaps why I struggled to find it. (To further confuse us mere mortals there’s also a breather pipe that feeds back to the top of the filler pipe which I think is just to let air out of the tank when filling it at the pump.)

The hose with the valve is part no. 93-5106 on the above drawing and the filter is 42-590A. No mention of a one-way valve.

I didn’t take the valve out of the tube to clean it but now I know where it is I might try that if things don’t improve, maybe soak it in some WD40 overnight.

Another update... Van was great for a few days after I took the breather tube off and blasted down it with compressed air, then began struggling to start again a couple of days later, so I decided to take out the valve and see if it needed a clean.

Was a bit of a pest to remove, but I got it out by pushing a metal rod slightly thinner than the inside diameter of the pipe through from the opposite end.

I don't think it is a one-way valve, as it has two sprung ball valves which are a mirror image of each other and I can't see how they'd do anything but let a small amount of air through both ways. Here's a pic (If you rotate the valve 180º you'll see the exact opposite of this on the other side):



So I can only assume it's designed to let a little bit of air in and out of the tank but prevent fuel spilling out. Air flowing both ways would make sense as if the tank heats up in the sun it's going to need somewhere to release the extra pressure as well as prevent a vacuum when fuel is being used.

The balls are white plastic. They looked quite clean and were moving freely, but I gave it a good clean out and blast with the air compressor and put it back in the tube. Will see how things go on the next trip.

That's what we like, good explanation and pics, better than my waffle.