Discovery 2 TD5 Lack of Power

Stanleysteamer said:

Do you not think, at all, that the stall test indicates a problem with the torque convertor? As that is the normal received wisdom.

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In this case i rely on what those who invented the stall test concluded and it's definitely a power issue as long as it needs more throttle to achieve the normal boost....

sierrafery said:

In this case i rely on what those who invented the stall test concluded and it's definitely a power issue as long as it needs more throttle to achieve the normal boost....
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I in fact had researched it elsewhere on the web rather than reading the handbook. Mea Culpa.
So yes, as always, you are right.
I am now standing in the corner with my dunce's hat on!

Gothicsera said:

If i was certain a different turbo would fix it then I'd splash a bit more cash.

But frankly I'm 100s of quid and 4 solid days into chasing my tail with it now and ultimately I need to decide what to do with it and how much more to throw at it.

I think sierrafery mentioned about exhaust restriction. I'm going to pull the centre section at some point and make sure that's not clogged or fallen apart inside and causing a restriction. It looks ok from the outside, but that could mean nothing.

Aside from a different turbo, injectors and exhaust everything else has been changed with no significant difference to performance.

Or perhaps the engine is just knackered.

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(I mentioned the exhaust post #15), I too changed the centre box for a bit of plain pipe, you can get one easy enough off the net, doing that made absolutely no difference to mine. But if a baffle has moved it could be the problem, in either silencer.

I had this problem on my wife's car earlier this year and when the guys came to change it they said that they couldn't take the box off cos it was too hot, it had got really hot due to the restriction but only at one end of the box. Never seen that before, but it may be a way of checking both boxes, starting it up, going for a run and then seeing if any part of any box is hotter than the rest.
In our case I could hear the baffle buzzing at certain revs.
Sadly no easy way to check unless you take them both off and can figure a way of doing it, running water through each one and seeing how fast it runs out the other end or summat. Thinking off the cuff here.
As for the engine being knackered, I doubt it, if it was there would be other symptoms and it could be checked with a pressure test or a leakdown test. All bar one cylinder I believe.

There seem to be a load of LR garages near you do you not trust any of them to do a proper diagnostic on it? Or maybe you have already done that and come up with nothing.

Really do feel for you. We have had the usual problems with ours, one being as you had a look for, the dreaded warped exhaust manifold, which led to me drilling and tapping bolt holes in the head, but still like it and use it a lot to do heavy long-distance towing.

Best of luck with it.

The fact is that the stall test result is not very far from normal so you are quite close, those with serious power issues are not exceeding 1800rpm, anyway before doing it again change the gearbox oil and filter(if the oil is black change it once without filter, go for a drive with many gear changes then change again with filter)

so as almost everything was ruled out back to this:

sierrafery said:

Very strange, i must admit that i'm running out of ideas, it's very strange to be low power at normal boost even if for that boost more throttle than normal is needed.... what's the air flow and IAT reading at full boost

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the MAF is useless for de-EGRd EU2 engine fuelling but it's good for diagnostic purpose, if the air flow is below 500 at full boost undo the pipe from the airbox(or lift the airbox lid and see if it affects it or not, if it's much better the air filter or the intake before it is clogged if not much change the intercooler can be full of muck

if this was ruled out (if you can afford some noise for a short time) undo the downpipe too and see the air flow reading then cos if no change no need to bother with the exhaust

IMO if you want more power don't throw more money on parts, make a compression test, if it's OK remove clean and leak test the intercooler(eventually the inlet manifold cos the EGR filled it with gunk), replace the turbo cartridge which is not very expensive) then the last thing you must pay for is a remap.

BTW, i really feel for you and i want to help but unfortunately with hawkeye is not very easy to watch live readings cos they are not all on the same page, try to find somebody with nanocom to record a full data log from a drive, there are two guys not very far from you, one in Ely other in Mildenhall but to contact them you must be registered to https://www.d2bc.net/index.php then magnify THIS map to see theyr's usernames and send PM.... fingers crossed

Whats the straw that broke the camels back? Auto box fill plug is rounded out (not by me). While it might seem minor, I not sure that I can be bothered with this any more. And I know it needs some serious rust repairs (bulkhead) before the next MOT.

I just wanted to get it running right before getting it remapped and having some fun in it off road for a year.

I just don't have the time or energy to spend any more on this and right now it feels like throwing good money after bad to be honest.

It's behaved like this since I've known the car, a good 7 years, and I don't think it's got any worse in the last 50k miles. It runs smooth, it doesn't make any noises it shouldn't aside from the odd trim rattle of a 25 year old car. The gearbox shifts properly. It's just so down on power it's a chore to drive it, and honestly I don't think it would cope with my intended use for it.

The intercooler hoses were very clean inside when I changed them, only the merest hint of a clean oily film inside them, not black, not caked, just exactly what I'd expect to see on an healthy engine. This tends to tell me that there's not a ton of blow by on the engine and the turbo is generally in good condition. I checked the shaft play on the turbo again this morning, feels absolutely normal to me.

The only oil it uses is what it leaks out, it doesn't burn any.

It starts on the button every time, even if it's been sitting.

The auto box isn't slipping, speed rises as expected with RPM once you take converter slip out of the equation. Just incredibly slowly. I've built quite a few performance auto boxes over the years (mostly American stuff, but they are similar enough).

Cylinder roughness is consistent across all 5 cylinders -2 to +2 - so very consistent.

With the new MAF fitted getting 65-66 at idle, 600+ at full throttle over 3500rpm.

It actually seems to pull just as well (if not better) at 2000-3000rpm than it does if you floor it. Accelerator inputs on ECU are working correctly.

Brake switch NO/NC contacts are doing what they should.

ECU is an MSB101193. Looks like it previously had the lid off. So i took a look, all standard inside and no oil.

I just can't throw any more time or money at this now.

As for why I haven't taken it to a 'specialist'. My labour time is free, theirs isn't. Ive built and modified and tuned many vehicles but this one has me stumped. And I'm loathe to spend even more money on it.

So sorry to hear about the gearbox filler plug, what an absolute pain.
We are still clutching at the straws that are breaking the camel's back.

So just two last ones.
Could the crank position sensor have moved? Altho Hawkeye might have picked up on that I don't know.
Also is the throttle rheostat thingy working correctly? Sorry cannot remember the correct term for it, senior moment. But I do know that their tracks can wear out and cause problems.

Totally, absolutely understand your reluctance to go to a "specialist". A lot of the time they turn out to know 9/10th of sweet FA, they charge like feck to do a diagnostic and think that will tell them everything and lastly but not at all leastly it sticks right in the craw not being able to do something without their help.

Sympathy continues.

Stanleysteamer said:

So sorry to hear about the gearbox filler plug, what an absolute pain.
We are still clutching at the straws that are breaking the camel's back.

So just two last ones.
Could the crank position sensor have moved? Altho Hawkeye might have picked up on that I don't know.
Also is the throttle rheostat thingy working correctly? Sorry cannot remember the correct term for it, senior moment. But I do know that their tracks can wear out and cause problems.

Totally, absolutely understand your reluctance to go to a "specialist". A lot of the time they turn out to know 9/10th of sweet FA, they charge like feck to do a diagnostic and think that will tell them everything and lastly but not at all leastly it sticks right in the craw not being able to do something without their help.

Sympathy continues.

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Throttle pedal position sensor is working fine according to Hawkeye.

I found the throttle had been set to 3 track in the ECU, not sure why and reset it to 2. Not that it made any difference.

Crank sensor is about the only thing i haven't touched/changed.

Currently waiting for the ECU to come back from a remap - it's an MSB so chip change needed.

In terms of where I got to it pulls ok to about 3k rpm, after that it's flat as anything and takes an age to pick up speed and rpm. It will rev out, eventually. Boost and air flow shows ok.

I had to wind the wastegate actuator in about 6 turns to see any noticeable increase in MAP beyond 215kPa. Clamping the hose will make it over boost.

As a recap;

Full exhaust changed, straight through front to back
All engine sensors replaced with OEM, except crank sensor which is still original.
Intercooler hoses changed
EGR deleted
Injector coding checked
Throttle pedal inputs OK
Fuel pump replaced with VDO
Fuel pressure regulator changed (genuine LR)
Injector loom changed
Injector clearances checked

Ive just bought a used, known good, turbo to swap on just to see if it makes any difference at all.

I dont have means to check compression on the TD5, but it runs super clean, starts perfectly, doesn't use a single drop of oil between services, and cylinder balance figures are within 2-3 rpm.

I've done a fluid and filter change on the auto box, fluid in it was clean anyway.

As an engineer this is one of those problems that is just bugging me to hell!