Diesel loss of power.

[TonyBongo]

Took Bongo for MOT and service today- first time on road after being in garage for 5 years. Fitted new batteries, fuel filter, and pumped out old diesel and put in new to get it there.

No problems getting there (including engine temp ok as reported on Haydn alarm), passed MOT fine, and service was change of fluids/ filters/new exhaust back box - nothing special. On way home, van was struggling on hills and then on the flat - RPM around 2-2.5k, seemed to be stuck at 40mph max and falling, and felt like wasn't getting up to top gears (hold wasn't on).

Had a quick look under banjo bolt, and while I didn't try taking out the filter, couldn't see any debris.

Any ideas/suggestions? I've searched online forums and a few people mention loose vacuum hoses. I can't see anything obviously disconnected, but what I think is a vacuum hose running forward from top of fuel pump to near the cam belt cover is not particularly tight at the cam belt cover end (can twist it easily between fingers) so maybe it's not sealed enough to create the necessary vacuum?

Ta

Tony

[rita]

Took Bongo for MOT and service today- first time on road after being in garage for 5 years. Fitted new batteries, fuel filter, and pumped out old diesel and put in new to get it there.

No problems getting there (including engine temp ok as reported on Haydn alarm), passed MOT fine, and service was change of fluids/ filters/new exhaust back box - nothing special. On way home, van was struggling on hills and then on the flat - RPM around 2-2.5k, seemed to be stuck at 40mph max and falling, and felt like wasn't getting up to top gears (hold wasn't on).

Had a quick look under banjo bolt, and while I didn't try taking out the filter, couldn't see any debris.

Any ideas/suggestions? I've searched online forums and a few people mention loose vacuum hoses. I can't see anything obviously disconnected, but what I think is a vacuum hose running forward from top of fuel pump to near the cam belt cover is not particularly tight at the cam belt cover end (can twist it easily between fingers) so maybe it's not sealed enough to create the necessary vacuum?

Ta

Tony

You really need to physically remove and check the filter/gauze ,you may also need to remove the sender unit a physically clean our the tank and in particular the pick up (suction line filter) ....but the first and easiest test to do would be to run the vehicle with the filler cap off or loosen it a bit to eliminate a vacuum in the tank that would cause fuel starvation owing to the clack valves sticking.

Good Luck.

[cmm303]

Does everything look and sound good around the turbo? Wastegate stuck open?

Does it have a cold start valve on the exhaust front section? Don't know how it would drive if this seized in the "on" position so just putting it out there!!

[TonyBongo]

Thanks for the advice - I'll have a look at those things.

When I stopped I did remove the filler cap but didn't notice/hear any indication of air rushing in.

I'll start with the easy stuff...running without the fuel cap on/loose, and then tightening the vacuum? hose that runs from the top of the fuel pump to near the cam belt casing.

To remove the filter under the banjo bolt, is it just a question of poking out the spring with a piece of wire of similar and then fishing out the filter/gauze? Looks a bit fiddly.

Cheers

Tony

[Northern Bongolow]

to get the filter out i use a cotton bud, spread it out then when it gets wet it expands and grips, or use the soft tip to hook it out.

at the other end of that vac pipe it goes onto the pump top, take off the top and check its not full of old oil, this can stop the rubber diaphragm from lifting so stops acceleration.

gently blow back to the tank from the fuel filter to clear the intank filter.

[TonyBongo]

Thanks. I'll try that lot at the weekend.

By 'take off the top' do you mean the top of the fuel pump?

I was poking round the engine tonight and noticed that the wastegate actuator rod would not move by hand. Is that normal? The engine was cold.

Thanks

Tony

[cmm303]

...
I was poking round the engine tonight and noticed that the wastegate actuator rod would not move by hand. Is that normal? The engine was cold.

Thanks

Tony

Yes. Its a pliers job, certainly on the earlier models. New shape models have different turbo with variable vanes which hopefully somebody else can comment on. Checking cold is fine.

This thread about sluggish acceleration is many pages long (partly thanks to some deviations c/o yours truly ) but may give some further thoughts as well as discussing the wastegate valve and actuator in some depth.

[TonyBongo]

Brief update.

-Tightened the pipe that runs form the inlet manifold to the top of the fuel pump.
-Removed the top of the fuel pump to check for/remove any oil on the diaphragm – was a small amount (1-2 teaspoons).
-Removed fuel feed from fuel filter and blew back into tank to clean filter in tank.
-NOT yet removed the filter from under the banjo bolt.
-NOT yet ran it with the fuel cap off/loosened
-NOT yet checked if there is a cold star valve on the front exhaust section

Took the van for a spin with the passenger seat up. Got up to about 60mph but still not right – particularly pulling up moderate inclines. Noted that there was no movement of the wastegate actuator, and that there were exhaust gasses escaping from under the turbo cover, so I’m now suspecting that the wastegate might be seized (the van had been sat in my garage for 5 years).

Any advice on what I should check first? Remove the cover on the turbo and try to manually move the wastegate or should I check anything else first? I’ve tried spraying some release agent onto the top of the wastegate spindle, but not applied any real force beyond finger pressure to getting it moving again. Looking at cmm303 videos am I correct in thinking that the actuator pushes (rather than pulls) the wastegate spindle (i.e. the actuator moves backwards)?

Cheers

Tony

[cmm303]

I couldn't budge the wastegate without pliers. The spring is strong.

Positive pressure on the actuator pushes the rod out to open up the wastegate valve. If it's stuck closed it won't cause loss of power. It limits turbo pressure by 'spilling' the exhaust flow straight into the exhaust when a certain turbo pressure is reached. But if it's stuck and not properly closed then it will reduce the turbo effectiveness.

[TonyBongo]

Ta.

I’ve managed to move the actuator with pliers and it springs back fine, so I think the wastegate is fine and my suspicions have moved on elsewhere.

When I drove the van to get a service and MOT (it’s first trip on the road in five years), it seemed fine. The problem with power only became apparent on the way home. As part of the service, I had the rear exhaust section changed, so I’m wondering whether the exhaust might be the source of the problem. My bongo does have the Northern Japan Exhaust Gas valve in the middle of the exhaust, so I’m wondering whether that is jammed closed – or the new back box has a blockage in it.

Need to figure out how to check the Exhaust gas valve (that it is open), and how to check for obstructions in the back box.

T.

[rita]

To take out a lot of the guess work it would be worthwhile using a test supply of clean fuel from a clean container connected directly to the FIP making sure that the Banjo filter/strainer and housing are perfectly clean , remember the fuel wont last as long owing to the fuel return (just in case you get a fright).

I would not Blow Back the line to the tank, this itself can cause problems.

Good Luck

[TonyBongo]

Got round to removing the filter under the banjo bolt last night.

While it didn’t look like a fishing net full of pondweed, there certainly looked to be debris in the fine mesh, so I cleaned it up.

Unfortunately it managed to slip out my fingers when putting it back and it’s managed to go down the hole the wrong way round (sure I couldn’t manage that again if I tried)!

After much swearing and fishing around with a hook , my Mrs is bringing home from work some rat nosed laparoscopic forceps that will hopefully fish it out…unless you’ve got any better suggestions!

T.

[cmm303]

Magnet? Might be stainless, so might not work.
Something sticky, double sided sticky tape round a small pad?
Small pipe on the end of a vacuum cleaner?
Turn the engine upside down and shake?

[TonyBongo]

I was tempted to turn the van upside down last night, but managed to get the filter out and back in the right way round tonight with the help of the laparoscopic forceps.

Loosened off the fuel cap, and went out for another test drive and I think everything is ok. Thanks for the pointers. I'll tighten up the fuel cap and take it out for another run another day to see whether it was cleaning the filter or loosening the fuel cap that has made the difference.

Despite getting up to 70MPH, I still couldn't see any movement of the wastegate actuator either when accelerating or decelerating. Under what circumstances should it move?

T

[cmm303]

Wastegate will open under heavy throttle at high revs. It starts to open with a pressure of 17.5psi but hopefully somebody can equate this to throttle and revs. I'd try driving hard up a steep hill.