Performance issues-2.5 td

[robdrinky]

Some months ago our Bongo developed a fault which i have been chasing eversince.
It would start and run fine untill we got to 40/50 mph 3000rpm then it would run rough and power would drop off.
Prior to this no work had been done apart from routine servicing which i do myself.
Infact the Bongo has been very reliable and we have owned her for quite a few years.

Initially checked for external leaks/damage to the fuel system,clean air filter,clean banjo filter and its orrifice-no issues found but problem continued.
Fuel filter replaced(although not old)and drove Bongo with fuel cap removed also temporarily removed air filter but no improvement.
Checked Turbo and associated pipework,Turbo turns freely with no visible damage and waste gate operates freely when functioned.
Air intake ducting and intercooler pipes checked and no issues found.
Next step was to take out fuel sender unit and disconnect then blow through the pipework up to the fuel pump.Fuel tank visibly clean and vent lines clear.
Vapour vent checked.
I did notice that there was no fuel pickup filter fitted.

Problem continued.
Next step was to check the TPS and i found it was giving erratic output so this was replaced.The fuel cutoff solenoid wire connection broke whilst removing the TPS so this was replaced as well.
Curiously the gear change improved(smoother)but the rough running continued.
Next suspect was the fuel pump its self or injectors,so this was removed with the injectors andtaken to a local diesel specialist for overhaul.
Unfortunately the problem continued

On the advice of a local Bongo specialist i connected a jerry can of fuel direct to the fuel pump and bingo she runs fine.
By a process of elimination i worked back through the fuel system and narrowed the issue down to the fuel pickup supply from the tank.
Proved this by cross connecting the fuel line with the return line(this pipe within the tank is a couple of inch's shorter)and she ran fine.

Puzzle-the pipe is a plain steel tube visibly clear with no damage.

Next i drained all the fuel from the tank and found an round black object lying in the forward part of the tank.
[URL=http://s263.photobucket.com/user/r ... .jpg[/img][/url]

This turned out to be the fuel pickup filter,this was then fitted onto the pickup pipe .
Over the weekend several test drives done and no repeat of the problem.
My conclusion is that under load the fuel pickup was being restricted by the fuel cannister 'lifting' in the fuel tank up to the fuel pickup pipe,therefore with the filter in place this holds the cannister down.
[URL=http://s263.photobucket.com/user/r ... .jpg[/img][/url]

Also puzzling to me is that the pickup filter must have been adrift all the years we have had our Bongo but the problem only started recently-go figure.

As ever the wealth of information on this forum was pricless,so thanks to all the people that take the time to post information.

[philpdr]

Excellent post.

[teenmal]

Yes that would cause your problem, and one of the reasons why you should Not Blow Back the suction line in situ .


http://igmaynard.co.uk/bongo/forum/view ... ot#p660093

[mikeonb4c]

Excellent post.

Agree++ though I don't quite follow it. What is the 'fuel cannister', and what are we looking at in the two pics. Also, what is involved in getting inside the fuel tank in order to track down the culprit filter etc. - I imagine that wasn't a 5 minute job?

[rita]

Excellent post.

Agree++ though I don't quite follow it. What is the 'fuel cannister', and what are we looking at in the two pics. Also, what is involved in getting inside the fuel tank in order to track down the culprit filter etc. - I imagine that wasn't a 5 minute job?

The first picture is the tank filter.
The second picture is the Swirl Pot referred to as "Fuel Canister"

To access these units you simply remove the sender unit flange on top of the tank.

[robdrinky]

Mike,The 1st pic is of the pickup filter which is push fit onto the pickup pipe inside the tank.
The 2nd picture-is a plastic tray also in the tank and acts a bit like a baffle or reservoir.
Access is by removing the fuel sender unit.

[mikeonb4c]

Brilliant and thanks both. So I'm guessing uyou have to lift the carpet / flooring and the rest is pretty quick to do?

Extremely useful post

One thought mind you. Had it really been loose for years or had age etc. caused it to work loose and drop off fairly recently. And if so, how long will pushing it back on keep it in place. Did it feel like a good secure fit when you pushed it back on?

[robdrinky]

I took out the seat then yes its carpet up to get to a access panel in the floor.Remove that and the top of the tank with the sender unit is then in front of you.
I have also considered that scenario-it is a positive push fit and i dont think there is enough clearance for it to come off again.
At least if i have any repeat issues that is the 1st place to look!

[mikeonb4c]

I took out the seat then yes its carpet up to get to a access panel in the floor.Remove that and the top of the tank with the sender unit is then in front of you.
I have also considered that scenario-it is a positive push fit and i dont think there is enough clearance for it to come off again.
At least if i have any repeat issues that is the 1st place to look!

Yup, it'll be a lot quicker 2nd time around and hopefully that won't happen