Lack of power in 4th and 5th gear.

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the_wolf

the_wolf

Well-Known Member
Posts
16,903
Location
Stonehouse, Scotland
This seems to be an intermittent problem although it's more often than not and it's driving me mental as it makes for a horrible drive. Around town driving and on generally flat roads it's mostly ok and has ok power in lower gears. When I go into the motorway or any national speed limit roads with hills though it basically completely loses all power. Today I joined the motorway and even when up to speed at about 65 as soon as I hit even a slight incline it basically dropped down to 45mph before I had to drop to 4th and even then it's a struggle to get it back up to speed. On todays drive however it then started randomly driving properly great and was brilliant for the rest of the drive up until the last 40 minutes when it completely lost any power again and I had to leave the motorway. I've replaced the fuel filter 3 times, fitted a new lift pump, ran a cleaner through it and still it's no better. Anyone any other ideas as I don't know what's going on? Literally the only thing I can think of is that I changed a pipe on the turbo that operates the wastegate as the previous one was worn through. I'm sure since then it's had these power issues but that can't be the problem. Hose I replaced is circled in the picture.

96 plate 300tdi 110
 

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miktdish said:
Sometimes the pipe going from the turbo to the steel pipe leading towards the intercooler delaminates.
The 90 degree one ... PNH1020

You can normally see it if it has, as a lump on the inside wall, you can't see it from the outside.
Click to expand...
Ill need to start having a look around all the hoses and pipes as I can't think of anything else it can be
 
Blocked fuel pipe/pick up?
Could also run but would not pull top gears. Fitted an override pump(was on racer) & this would pull more fuel than the standard lift pump. Piece of wood in pipe had gone up it,fitted a series gauze on the pipe after
 
Hicap phill said:
Is the waste gate pipe been restricted by the vacuum pressure(collapsing pipe)& not allowing full movement of the waste gate?
Click to expand...

As far as I'm led to believe it's positive pressure so this shouldn't be the case. Only other things I could think of relating to this were that the wastegate is seized from being parked up and not opening fully, or the pipe I fitted is ballooning under pressure and not allowing the wastegate to fully open. This should overboost the turbo though
Hicap phill said:
Blocked fuel pipe/pick up?
Could also run but would not pull top gears. Fitted an override pump(was on racer) & this would pull more fuel than the standard lift pump. Piece of wood in pipe had gone up it,fitted a series gauze on the pipe after
Click to expand...

The fuel pick up was replaced during the chassis swap, id had this low power issue in the short time I was driving it before that.
 
+1 on the turbo hoses, can be a leak, it disconnected or sinply desintegrated. As she did have full power before loosing it again, maybe a leak or a loose hose. Had that on one of our other cars, also a turbo diesel engine.
 
hef19898 said:
+1 on the turbo hoses, can be a leak, it disconnected or sinply desintegrated. As she did have full power before loosing it again, maybe a leak or a loose hose. Had that on one of our other cars, also a turbo diesel engine.
Click to expand...
I'll have a look around today and check all of them. I think it is a turbo/boost issue rather than a fuel one
 
Suspect this may be my issue then. All other turbo hoses fine apart from this, the boost control pipe from injection pump to turbo has at least 1 pinhole worn through. Going to get a new one today and see if that sorts it
 

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Well that made absolutely no difference. Replaced the boost control pipe and the air filter for good measure, im just back a test drive and unfortunately it's still exactly the same. I can hear the turbo spooling up in lower gears and I've no problems with power in 1st, 2nd or 3rd but as soon as I put it under load or attempt a hill it just loses it. The only other issue I can think is fuel but if I try yet another filter thatll have been 4 now.
 
hef19898 said:
Does it have an airflow sensor?
Click to expand...
Nope, and no EGR. Checked pick up pipe last night and that's clear, I also looked inside that tank and it's immaculate inside too. What I did find however is that when I removed the fuel filter I got a ton of diesel chucked out at me which isn't normal, it's as if it was held in there under pressure. I'm going to try driving it this morning with the fuel filler cap removed incase there's a blocked vent in that causing a build up of pressure and reduced fuel flow. Failing that I'll try yet another fuel filter
 
Power (the ability to do work) come from a (rich) mixture of air and fuel.

I would imagine that in 3rd pulling 3500 rpm you would be in the power band and using more fuel than when you are in 4th or top with a less revs ??
The Turbo makes a diference too in that it compresses the fuel/air mix so there is more entering the combustion chamber but again this is typically lower when you are in higher gears at lower revs ...

Have you checked the compression on the cylinders ?
Are you injectors providing a clean pattern ?

It isn't a race car - it's a lumpy old brick of a Landrover ...
 
miktdish said:
Power (the ability to do work) come from a (rich) mixture of air and fuel.

I would imagine that in 3rd pulling 3500 rpm you would be in the power band and using more fuel than when you are in 4th or top with a less revs ??
The Turbo makes a diference too in that it compresses the fuel/air mix so there is more entering the combustion chamber but again this is typically lower when you are in higher gears at lower revs ...

Have you checked the compression on the cylinders ?
Are you injectors providing a clean pattern ?

It isn't a race car - it's a lumpy old brick of a Landrover ...
Click to expand...
Certainly not expecting it to be rapid or drive like a modern car, I've had it long enough to know that but there is a noticeable drop and complete lack of power when under load. It never used to be like this so something must be causing it but for it to randomly start driving great the other day then to back to being poor seems odd. I haven't checked compression or injector spray pattern but if a new fuel filter today doesn't sort it I'll just be chucking it into a garage as I can't keep throwing money and time at it. The build up of fuel and pressure inside the fuel filter leads me to believe it's blocked but I've no idea how. I drove it this morning with the filler cap off and this made no difference.
 
That sounds like the boost isn't getting through to push the plunger down on the fuel injector pump- forget it's proper name now.

As too why it is intermittent that is a mystery -

A boost gauge T'd in just before the pipe goes into the injector pump might give you a clue
 
D1Nut said:
That sounds like the boost isn't getting through to push the plunger down on the fuel injector pump- forget it's proper name now.

As too why it is intermittent that is a mystery -

A boost gauge T'd in just before the pipe goes into the injector pump might give you a clue
Click to expand...
I think the wastegate was seized a little so I've freed that up and I've also found that the right angle hose from the turbo is swelling under acceleration so I'll replace all the hoses. If still no luck I'll need to check the boost. I wanted to check the boost diaphragm but the screws are pretty solid and I didn't want to risk chewing them up
 
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