Hi. My truck is behaving strangely and I'm having a hard time getting my head around it. I've not had chance to poke around as it my only transport to work and I don't want to cock it up while it still runs! It's a 2005 classic shape 4 life 5 speed manual.

When driving full throttle from under 2000 rpm in first or second, 9 times out of 10 I get a bit of a "pshhhhhht" noise and no power from the engine. It will Rev over 3k but not willingly. If I feather in the power till higher in the rev range then use full throttle it's quite responsive and go all the way up to 4000 rpm. It has done this to me once or twice in higher gears at motorway speeds and I've not really been paying attention and had the EML come on. No idea what the code was as I don't have access to any diagnostic equipment.

I'm guessing the hoses are OK as it boosts well under certain conditions. I've also heard when boost pipes are off or holed and the make a different noise to the one I'm hearing. I've had a scour through some other posts about boost issues and not sure if this is the same issue as others have had. Not really sure where to turn next. If anyone could share their experience it would be greatly appreciated.

Many thanks
Greg

Hello mate
Years ago I suffered from over-boost with mine(orange EML came on)so I took a trip back to the dealers and they adjusted the boost for me (there is a handy how to on here of how to adjust it)
Jump forward many years and I had a pipe come loose from the turbo which gave a "pop" sound then a similar sound to yours. I fixed this with a new jubilee clip.This happened at lower revs incidentally.
Mine also becomes hesitant (usually around 2,250 revs) on rare occasions, a change of fuel filter cures this one.
Most classic engines don’t want to rev over 3,000. They are lumbering old commercial diesel engines after all (and that's coming from someone who's a fan). Most will start to run out off puff when you get near the 3,000 range and are just screaming for you to change gear. That said, mine will easily rev past 3,000 without hesitation but then I have fitted a K&N filter and have a straight through exhaust so that may well help.Just because mine can rev past 3,000 doesn't mean that I take it past that point though. Just remember that's it's 2 tons of dinosaur diesel you're driving and not a sporty hot hatch , so regular trips up to 4,000 in the rev range will be more than the engine is used to and sooner or later isn't going to end well.
If it were me, I'd be double checking all the hoses and pipes are on tightly and have not got any splits in them and then taking it somewhere that can read the codes (I think it needs to be a MUT3 reader) to find out what's wrong. Have you had the truck long and has this been going on for a while ? or have you had any work done on the engine recently and this has just started ?
I'm sure if others have any ideas that can help you they will post on here in due course

I have had the truck 4 years and it has done 70,000 miles in that time. I do like to exercise an engine every now and again to blow the cobwebs out. It has been doing it for a little while but has become much more pronounced. It has always quite a willing engine and I know the current behaviour isn't right because I can make the EML come on when I want it to. It has become a problem when trying to get away from junctions quickly.

I will check the hoses but I'm not convinced it that. I've heard turbos spinning up with no load ands not that sound.

get a boost gauge on it to see what the turbo is atually putting out and when

Lol you make it sound so easy :-)

Just had a quick look. The intake hose(?) above the oil filter wasn't seated as well as it could have been. Which I have reseated and will have a quick test of this afternoon.

There seems I be a fairly complex (to me) vacuum system going on ending up at a diaphragm pulling on an arm. Are any of the sensors in that vacuum system suspect? I'm on about the ones on top near the egr.

Should I be able to move the arm on the turbo with one finger? Should it squeak? Neither of the two adjusting screws look like they will come into contact with the arm. Is this correct? It may contact one but I don't want to ruin what I assume is a diagphragm by over stressing it.

see the how too section for how to adjust ur turbo it will explain where it should sit ect

but if u had a boost leak on the intake hose that could cause issues

Gonna ask a silly question now.

How would an air leak on the intake side (before the turbo) affect the boost? Shirley it's just one big air leak and that's the point?

Gonna ask a silly question now.

How would an air leak on the intake side (before the turbo) affect the boost? Shirley it's just one big air leak and that's the point?