Bongo Fury

Update on my problem....

Took the vehicle to Bell Hill Garage (many thanks to the attention given by Tom and Kieth who are well recommended by me), but on 3 different occasions from cold the Bongo didn't show any of the symptoms of the problem I previously described. Yes BDC, hmmmm......

So after sleeping in Bungle on Friday eve (xmas pub crawl in Bath) I parked the Bongo outside of Bell Hill on Saturday afternoon and left it there for 53 hours (2 car problem) until trying it again on Monday evening in the freezing weather. And it started again and drove home several miles without a blip.

No problems again today (Tuesday), but the weather has been cold since I last had the problem.

I have noticed that the problem has only been worse when the weather is warmer so it indicates that expansion is allowing air into the softer (when warmer) fuel pipes which has been allowed to settle. At the moment this is my perception of the problem, and also Bell Hill have suggested like others that it was a problem with air getting in the fuel pipe when it was left. It's freezing outside and I fully expect the vehicle to start easily without problems tomorrow.

I suspect that I will have to wait for warmer weather until it happens again. Maybe then I can investigate the problem further.......

Sounds to me like you could have a water sediment issue in the fuel tank. This is either blocking the pickup or causing great slugs of water to be gulped into your fuel system.

Not saying it isn’t an air in fuel supply issue, but the intermittent nature of this suggests to me that this is not the case.

Water can collect in the fuel tank getting there through condensation or other means. Over time, a layer of fungus (Cladosporium Resinae) on the layer between separated fuel and water can develop. This causes us big problems in our aircraft as it produces sediment that is corrosive. I think the bongo fuel tank is plastic so this should not be an issue, but the sediment will play havoc with the fuel pickup in the tank if it is not eradicated. Most pickups have a gauze or filter on the end that will block.

Aircraft get round this problem through three main methods:

1. They have water sediment drains located in the low points of each tank. These are checked regularly for water and drained if required.

2. They use a fuel system icing inhibitor (FSII) which is also a fungicide in the fuel. We have limitations on how many refuels the aircraft can receive without this additive and it is all carefully logged.

3. Fuel tanks are fitted with a recirculation scavenge system which in effect sloshes the fuel around the bottom of the tank, mixing fuel with water in the bottom of the tank before delivering it to the engines. The engines burn this quite happily as it is in such small doses, as will a diesel engine.

If you don’t run your tank low frequently, the fuel will not slosh and mix with any water. The fact that you run veg oil (no fungicidal additives or detergent) would only exacerbate the problem if the fungus has started to develop.

I am not saying this is definitely your problem but it may be worth running your tank down, taking it off, cleaning the pick up and rinsing the tank out with neat diesel. If this cures your problem, I would then suggest running your tank dry every few tank fulls and running on just diesel for ¼ to ½ a tank before returning to your veg mix.

In the first instance, at least try running it down very low, refilling with ¼ tank of diesel and running that down before refilling it again. Don’t put any more veg in until you are happy the problem has gone.

Hope this helps. Sam.

In the first instance, at least try running it down very low, refilling with ¼ tank of diesel and running that down before refilling it again. Don’t put any more veg in until you are happy the problem has gone.

Thanks Sam,

I probably haven't let the tank run down low more than half a dozen times since I bought it in May.

So, apart from the fact that I filled up yesterday I will try your tips when I manage to do the mileage required (only working 4 more days before the New Year so will take some time to use the existing fuel).

Paul

No problems again until Friday, Saturday and today....

Today was interesting as Bungle started ok. Then started to choke, then died. Started again after a couple of long turnovers and then choked again. Wouldn't start after that so gave up a couple of long turnovers ....

I lifted the drivers seat and was checking around for 5 minutes or so and then turned the engine over. Hey presto, Bungle started almost immediately and ran perfectly at tickover for a few minutes with no throttle.

Stopped the engine and started it again whilst looking at the injection pump and noticed that the actuator didn't pull in. Now for several starts after that the actuator didn't behave in the same way... what I mean is that sometimes when I had turned the ignition on (lights no starter) the actuator immeadiately pulled in, other times it waited until after the engine was started, and another time it wouldn't go in at all.

Questions here then is how is the Actuator actuated? Is it electrical (through the injector pump), air vacuum (probaly not), or fuel pump vacuum when the pump is switched on? And is it thermostatically controlled?

And can someone at the same time tell me what the microswitch does?

I know now that the next time is doesn't start I will be lifting the seat to see if the actuator is sticking or not....

Is the fuel filter tight any air leak at the filter would
cause the same problems also on top of the filter
is a plunger this is to pump fuel through manually
if you run out IE prime the injection pump, I have
not heard of it happening on a bongo but the diaphragm
in this plunger can split letting air in.

Sounds like you could be onto something interesting BB. I got my workshop manual out and had a browse but was none the wiser. Had a good look at the ECU section and e table that lists voltage testing points and there's clearly a lot of interesting stuff going on involving the fuel system, but since I've no idea what your 'bit' is called in the manual its hard to make a connection.

One interesting item I did spot was a note suggesting the length of time the glowplug indicator light may stay on after turning the key to the ignition position would vary depending on the temperature of the coolant. This fact might settle the debate about the significance of varying times before peoples (Bongo) lights go out

Keep us posted and good luck

If you are talking about the actuator under the fuel pump/regulator then this is vacum operated.

When I was fitting my cruise control the other day I noticed that mine too did not always appear to move when starting.

What I discovered was that it moved once, and whilst there was still a vacum in the pipework it remained in the 'moved position' even after the engine had stopped.

1, Stry starting the engine andwatching the acutuator move.

2, Then stop the engine.

3 Now pump the footbrake with your hand until you feel the servo assist dissipate (about 7 to 10 pumps)

4, As the vacum is dissipated you will probably see the actuator return to it's resting position.

5, Start it up again and see if it actuates again.

It really does sound like your problem is cold weather related. Either gloopy veg oil or possibly even ice if water has got into your fuel tank/delivery system.

Next time it happens, try and get straight to the fuel pick up in the tank and see if there is any kind of obstruction.

Let us know what your findings are. Where are you?

Hope this helps,

Sam.

If the actuator is the one that is on the side of the injection pump
all that does is speed the tick over up when the engine is cold or
you turn on the air con, it wont stop it starting.

Have you got a cold start valve on this?

Ralph wrote:If the actuator is the one that is on the side of the injection pump
all that does is speed the tick over up when the engine is cold or
you turn on the air con, it wont stop it starting.

Yes, it's the one on the side of the injection pump.

Part number 24-8002 here
http://www.lushprojects.com/bongopartsmk2/1R29911.gif

I have never had a problem starting. Not from a straight cold start anyway. Just a problem keeping the engine going after about 20 plus seconds after the initial clean START after leaving the engine unused for at least 8 hours.

BongoMTBer wrote:Have you got a cold start valve on this?

I have what is on the link above. I have never had the Japanese cold start, dual battery setup on this vehicle.