Bongo Fury

Hi all.

The ongoing saga of my poorly Bristol Bongo is still ongoing! I have today removed the EGR pipe and the two valves and inspected/cleaned them. The valves were nice and clean anyway, and moved freely inside.

The issues with the poor starting, limp mode, no response to the throttle (but free revving when out of gear) and stalling when wheels are on full lock remain.

I have now replaced the TPS, ECU, TCS sensor and a few temp sensors.

The wheels are 205/65/15's all round - is that likely to be a problem?
I'm getting mixed messages with regards to the tyre sizes. The tyre shop said I need the same size all round as it's a 4WD - but shouldn't they be different front & back?

Seriously getting to the point now where I'm wondering whether it's worth keeping... it's costing me so much money to not be achieving anything

Any other suggestions?

Hi Marc,

With the 4WD, it's important that the tyres all have the same overall diameter.

From the factory, they have narrower fronts than rears, but a higher aspect ratio on the front. The overall effect is that all 4 tyres have the same (or very close) diameters.

You can obviously fit 4 identical ones - and they will all be the same diameter. Most owners tend to do just this - and it means that deciding on what size spare to carry is easy!

Re. the running issues I'm not sure, but that does sound like poor fuel flow. Have you changed the fuel filter recently?

I have changed the fuel filter.
The steering wheel shudders when pulling away with the wheels turned (such as pulling out at T junctions). I wondered if that was a result of wrong size wheels - but since they're all the same, perhaps that isn't the issue.

Someone on another forum says that wheels should be different sizes on the Bongo!

The size tyres you have now are fine. You will find that both 2 and 4WD Bongos do tend to 'crab' a bit when going round a tight corner at slow speeds. It is possible there is a problem with either diff or the transfer box, but what you describe seems normal.

It is possible there is a problem with the power steering rack or pump it it's stalling at full lock, or it could be the idle revs are just too low.

Have you checked / changed the glow plugs? Have you got the older injection pump or later drive by wire type? Any signs of fuel leaking from around the pump? Could be dodgy seals letting air in/diesel out.

Many thanks for your help and the suggestions.
My Bongo is the drive by wire sort.

I'll check the glow plugs tomorrow.
The idle revs sit around 800-900 rpm, but I'll check the cold start tomorrow too.

There's no fuel leak.
The pump has been checked when I had my ECU and fuel pump sensor changed.

Will have to investigate the power steering, and ABS sensor.

Are your CVs worn perchance. Is it time to have a Bongo specialist give a view?

The van has just come back from a Bongo specialist!
There are no knocks that would suggest a CV problem. It's losing revs, and in particular in reverse gear.

Have spent hours on it this weekend, and this evening it's running so roughly that I've had to abandon it on my parents driveway.

The EGR valves don't move when viewed in place whilst the engine is being revved, so presumably they will need replacing.
I'm getting three fault codes when using the diagnostics:

•P0400 - Exhaust Gas Recirculation Flow Malfunction
•P1228 - Wastegate Failed Open (Under pressure)
•P1402 - EGR Valve Position Sensor Circuit

I can see how they would affect the rough running, poor power and performance, and the engine going into limp mode. But I can't see how they are linked to the stalling when the wheels are tuned.

Getting to the point now where I think I'm going to trade it in for an older model and cut my losses. I've lost all confidence in it

Having wanted a Bongo for so many years - I borrowed to the max to buy one, and to have all these problems is really getting to me! I've paid out about £2k on various parts and repairs, and it's still no better off. I can't afford to keep paying out, and it's my only car. I'm really not sure what to do with it now...

You have a vacuum circuit fault.

There are various vacuum solenoids, and the circuit is difficult to diagnos, but if y ou persevere you will have all these issues sorted when you identify which solenoid is leaking all the vacuum pressure away.

Thanks Dave.
I'll get in touch with the local Bongo specialist - and let him take a look at the solenoids and hoses.

MX5Marc wrote:Thanks Dave.
I'll get in touch with the local Bongo specialist - and let him take a look at the solenoids and hoses.

How specialist is this specialist? Hopefully Dave has pinpointed it. Good luck keep us posted.

Regarding the stalling -

When you are n full lock, the effort required to get moving is significant;y greater than with the wheels in line, even more so due to the 4WD system trying to turn all 4 wheels at the same speed, which the wheels don't want to do.

Now, a van with no fault, you just have to push the throttle a bit harder.

You mentioned earlier that you have no throttle response,but free revving out of gear - this sounds like the van is extremely low on power, so this could account for the stalling - full lock is just too much for it in the current state.

To expand on my brief post last night (after a couple of pints!).

I looked at a van about a year ago for a friend which had a 0400 and 1228 faults. I don't recall it having a 1402 as well.

However, what I did diagnose was that the EGR is vacuum powered, and on the later (drive-by-wire) vans, the variable turbo is also vacuum powered. Although the fault code says wastegate, you actually have a variable vane turbo, which doesn't have a wastegate. The failed position on these turbos is minimal boost (hence the limp-mode effect).

Here's a wee ditty on how the variable vane turbo works. The earlier ones are more basic - once the manifold pressure gets to a certain level, that pressure is used to open the wastegate and dump the pressure. If these fail, then the wastegate stays shut, and you get mega performance (and something will go bang). The variable vane type rely on vacuum to drive the vanes to the position demanded by the ECU. Low boos position needs low vacuum, high boos needs high vacuum, so if you have a vac fault you get minimal boost.

The van I was looking at I could temporarily fix by disconnecting the vac pipe at the vac accumulator (plastic ball, towards teh rear of the passenger's side of the engine). Once the vacuum had been re-established, the van ran OK, until randomly the glowplug light stated flashing again.

In then end, the owner sold the van whilst I was away on a business trip, so I never discovered the eventual culprit.

By isolating various sections of the vacuum system, and seeing what (if any) faults clear you or your specialist should be able to narrow it down.

There's a steel pipe right in front of the engine, running vertically, which is part of the vac system. You can get to it from the driver's side (blind, but you can feel it). There's a 'T' point on this pipe which has a rubber cap n it. Commonly used to connect to cruise control kits (not really applicable to later drive-by-wire vans). It may be worth checking that this cap hasn't perished & fallen off..

It does sound like a nightmare, and as far as I could tell there's not much in the way of decent information about the vacuum system, so it will need a persistent and clever mechanic to get to the bottom of it (and quite probably a fair bit of luck!)

HTH
Dave

MX5Marc wrote:
The EGR valves don't move when viewed in place whilst the engine is being revved, so presumably they will need replacing.
I'm getting three fault codes when using the diagnostics:

•P0400 - Exhaust Gas Recirculation Flow Malfunction
•P1228 - Wastegate Failed Open (Under pressure)
•P1402 - EGR Valve Position Sensor Circuit

good post dave. .
when the egr valve sticks or the vac supply fails it comes up with the last of your 3 codes. either the operating solenoid has failed or the egr is full of crud, both of which are faults that the ecu can pick up via the position sensor on the egr valve, you could try bridging out the egr position sensor to fool the ecu or find the stuck solenoid or strip /clean /replace the egr valve, (these are a service part so dont last forever).

Many thanks for all your advice.

I have replaced the EGR solenoids now - and checked the valves were operating and not too dirty (the valves I bought as a replacement were in a much worse condition than mine, so didn't swap them).

We found an air leak from the manifold to the EGR pipe, which we have sealed using exhaust paste.

Running it yesterday, we had no fault codes showing.

The van started lovely this morning, and when throttled didn't drop any revs.
However, after running for 10 minutes or so, the glowplug light started to flash and we got the following codes on the diagnostics:

1228 Wastegate
0120 TPS
0400 EGR air flow.

The TPS has already been replaced with a new one - and we tested it yesterday by swapping the new and old over and back again. The old TPS instantly threw up flashing hold and glowplug lights, whereas the new didn't.

I guess it's a vacuum issue, so we'll need to check all hoses.
I couldn't see the

vac accumulator (plastic ball, towards teh rear of the passenger's side of the engine

that you mentioned Dave - there doesn't appear to be such a thing on my engine

Is there anything else that could cause a TPS error code other than the sensor itself?
I don't want to have to buy another one at £200 a pop!

Thanks as always

get a good hammer and whack the egr valve. may just be a cheap fix.

Can't help you there, all my hammers are bad.

Bad hammers.