Engine holding back at 2900rpm

[Gazeddy]

is it fly by wire or cable throttle? take the boost pipes off then check if it will rev up if not id say your problem is fuelling if it revs up you got a problem air side.


is the exhaust clear

[BoxCleva]

A quick Google suggests that the de-lamination of induction pipes is a common issue.

[andytats]

I've come to the conclusion I hate Diesel engines & discos
Just be out side again looking to try and find the problem with no luck.
Removed the air inlet manifold then started the car with the same result. Removed the pipe to the turbo started engine again turbo is turning fine with the engine running.
Checked the lift pump
Checked all the fuel lines
So I'm left with the injector pump but I don't want to spend £150 on one incase it isn't that
Think I'll call the RAC out to see want they say

[andytats]

I've now had the RAC out we found one of the problems if it cutting out when I drained the sediment tank I didn't put the drain plug in all the way so it was sucking in air ( drift was sort of right with the air) but we are back to the main problem it's still holding back at 2900rpm and black smoke

[Drift]

Well a bit little right
Did you change the fuel filter before or after draining the crap out of the tank?

[andytats]

The filter was changed two months ago. When I clear the crap out of the sediment tank I also took out the drain plug from the filter to cleaned that too. I did notice though when I emptied the filter out into a jar at the bottom of the jar there was like fatty deposits like someone in the past has used biofuel. I've ordered a new filter so I will fit that then see how it runs then.
Until then thanks for all of your help

[Drift]

Any time Andy, I know you help loads here too
I think you have cracked it, if its had WVO in and the tank cleaned out it will have disturbed some of the crud and its in the filter blocking it. It has not been to warm lately so some could have congealed in the fuel lines, best get a hot blower on them and plenty of diesel to soften the crud up and flush it out.
I would get two filters as it could take that many to get clear.
As the weather warms it should clear naturally and should not reoccur with straight diesel

[Bearcat]

Had a Rover in with a similar problem, would not rev beyond 2500rpm, Did not missfire, just as though it was towing 3 Fronty's.
It was the pipe IN the silencer it had dropped partially blocking the gas flow. Worth a look as a last resort

[zebadee]

Glad to hear you/read you are narrowing it down to the problem Andy, thanks again for today.
Dazza.
p.s don't forget to make that phone call

[RatCav]

Overfuelling maybe ... hence the black smoke and poor burn (too much diesel to air).

That could be a number of things off the top of my head. Does it have a boost sensor on the inlet after the turbo. If there is a split after that then it would think there is more air going in than there actually is. Ups the fuelling and you run too rich.

Other things are blockages in the inlet
Split hoses (especially around the clips)
Leaky manifold gaskets (spray around with WD40 and listen for the revs to go up)
Contaminated fuel.
Turbo actuator jammed open partially
Cracked turbo actuator flap housing (on the turbo itself)

The last two would allow the exhaust gasses to bypass the turbo impeller and therefor the turbo won't spool up properly. If the pump works off the throttle and opens according to pedal position then it will overfuel.

[RatCav]

Another thing to look at is blocked intercooler.

Whip it off and swish some petrol around inside it.

Shove some injector cleaner through it as well as the injectors could be partially blocked.

[RatCav]

Reading the forums, they also suggest that EGR faults can cause this.

[andytats]

Come to think of it where I haven't had the money to fill the fuel tank all the way like I've always done. I've only been put in about £20 at a time for the past couple of months so it could be picking up a lot of crap from the bottom of the tank which has then coursed the problem maybe ??

I'll pop out and get some injector cleaner and some fuel
I will order a new air intake manifold gasket
Then I'll spend a day cleaning the intercooler and pipes

[RatCav]

Age old vacuum line issues can do this on all makes of car as well. Might pay you to check them all as well.

[andytats]

Well I've just done the following item
Air filter
Oil filter plus new oil
Fuel filter
Glow plugs
Inlet and exhaust gasket
Cleaned all air inlet pipes and intercooler and manifold

With no change to the bad running at 2900rpm
I don't know what to do next apart from a new turbo at a cost of £150 even though I'm sure if that is the problem

[2much]

hi andy,

my two penneth;

i very much doubt it is the turbo as in theory it should run without it...

you have mentioned it before but i would say fuel pump/distributor block (not sure if they are combined on disco) - this can be cause of pulsing at certain revs when wearing and then low pressure at injectors and/or poor timing/delivery of fuel at certain revs.

also some assemblies have a mechanical governor built in which can wear and so cut in at wrong engine speeds.

if it was me i would go that way before turbo

[andytats]

As I didn't have much to do today I've been surfing the net to try and get to the bottom of this problem.
I think I know now what is wrong.
It could be the turbo actuator / wastegate in the exhaust manifold has stuck in the closed position which is starving the turbo of gas flow so it's only running at a idle so at speeds it's not pushing enough air into the engine which is why the engine is holding back at speed. Because the engine isn't getting the right fuel and air mixture that is why I'm getting a cloud of black smoke.
So I will try and take the turbo and exhaust off so I can get the wastegate moving again.

[2much]

probably wrong but thought the wastegate was like a pressure relief valve only - when set pressure reached it released the "extra"??!

not sure how being shut would affect this unless there is some link to fueling system, meaning overboost and not enough fuel to cope?

good luck

[Hound Dog]

It's nothing like that.
She's got the hump cause Andy's got another fronty.

[RatCav]

Nope Andy ... the wastegate is shut all the time until the turbo builds up too much pressure in the compressor (inlet) end. Then the pressure is enough to force down onto the actuator opening the wastegate in the exhaust end. This allows an easier path for the exhaust gasses to go through, bypassing the vanes on the exhast end of the turbo shaft. That means the turbo slows down and produces less pressure therefore less boost. If anything its stuck in the open position.