Disco 2 Intermittent loss of power on gradients

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kasapeky

New Member
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Happy New Year all.
2003 TD5 Manual
Please help. I've had a good search but I can't find the exact symptoms that I'm seeing in my Disco.
He's been chipped by Dynachip Mike and runs really well, except:
Hitting a climb in 5th gear and low revs. When he's working hard I feel a jerking and then loss of power. At this point I can drop to 4th and then 3rd, but still nothing there until I turn him off and back on again.
This has been going on for over a year. Fault code is Driver Demand, but I've put 2 throttles on and no joy, so that is a symptom not the cause.
Things tried:
  1. Replaced injector harness as was getting oil up the loom to the red plug at the ECU. ECU also sent off for diagnostics, all fine.
  2. Mass Air Flow Sensor and air filter replaced.
  3. Fuel filter replaced.
  4. Turbo wastegate worked and oiled, but didn’t really know what I was achieving with this one..
  5. Fuel pump replaced.
I keep thinking that it may be to do with the turbo actuator. Do we think so?
Any thoughts gratefully received.
 
tilly2 said:
Hello, welcome to the forum.I cant be bothered with that introduce yourself rubbish.. No one reads it anyway.

Initially it sounds like an overboost issue, however, have you read this thread... https://www.landyzone.co.uk/land-rover/fault-3141-driver-demand-has-been-faulty.302446/

I have almost the same issues, of low power, and driver demand intermittent faults, so will watch this thread...
Click to expand...

Cheers Tilly, I was worried about skipping the intro and getting shouted at!

I've had a look at that - I can wield a spanner but crap with electrics so that went right over my head. I'll certainly go that direction depending on any other ideas.
Cheers
Pete
 
It deffo looks like overboost, symptoms sound exactly like what happened to me when my actuator mounting studs came loose..
Re the wastegate actuator, have you checked you have at least 13 threads between the locknut and the end of the threaded portion of the actuator rod?
If you have, sorry to have wasted your time.
But if you have a chipped ECM I have no idea what effect that can have.
 
Stanleysteamer said:
It deffo looks like overboost, symptoms sound exactly like what happened to me when my actuator mounting studs came loose..
Re the wastegate actuator, have you checked you have at least 13 threads between the locknut and the end of the threaded portion of the actuator rod?
If you have, sorry to have wasted your time.
But if you have a chipped ECM I have no idea what effect that can have.
Click to expand...

Hi, thanks for that. I count 12 threads visible. I'll adjust tomorrow and report back!
Is an overboost issue and wastegate actuator adjustment the same thing, or should I be looking at something else for overboost?
Cheers
Pete
 
Have you checked live data to see what max turbo pressure you have? I also have stage 1 remap but my wastegate had to be adjusted to 11-12 thread to achieve about 235kPa and no overboost. But in your case maybe even the 12 is too short... it can vary as the parts (actuator and even the turbo) are not exactly the same.
 
kasapeky said:
Hi, thanks for that. I count 12 threads visible. I'll adjust tomorrow and report back!
Is an overboost issue and wastegate actuator adjustment the same thing, or should I be looking at something else for overboost?
Cheers
Pete
Click to expand...
I'd go to 13 to get back to "normal", though I doubt 1 thread would make that much difference.
Overboost occurs when the turbo provides too much boost, i.e.overboosts. this happens when the wastegate doesn't open, or opens too late.
This could be a physical/mechanical matter i.e. the wastegate jamming, even though the wastegate actuator is operating the rod, as best it can.
Or then the tube that goes to the actuator could have a fault so the wastegate doesn't get enough exhaust/turbo gas pressure to operate well.
The diaphragm in the actuator could be split.
Etc, Etc.
Here's a thing you might want to look at to answer your question but the short answer is no, they are not necessarily the same thing.
.https://www.aet-turbos.co.uk/turbo-...s held shut,the turbine, regulating its speed

Best of luck.
 
Stanleysteamer said:
I'd go to 13 to get back to "normal", though I doubt 1 thread would make that much difference.
Overboost occurs when the turbo provides too much boost, i.e.overboosts. this happens when the wastegate doesn't open, or opens too late.
This could be a physical/mechanical matter i.e. the wastegate jamming, even though the wastegate actuator is operating the rod, as best it can.
Or then the tube that goes to the actuator could have a fault so the wastegate doesn't get enough exhaust/turbo gas pressure to operate well.
The diaphragm in the actuator could be split.
Etc, Etc.
Here's a thing you might want to look at to answer your question but the short answer is no, they are not necessarily the same thing.
.https://www.aet-turbos.co.uk/turbo-tech-101-what-is-a-turbo-wastegate-and-how-does-it-work/#:~:text=How does a wastegate work?&text=The wastegate is held shut,the turbine, regulating its speed

Best of luck.
Click to expand...

Hi,

I have been out up and down my test hill many times this morning. I thought we'd cracked it with the actuator. Moved it out to 13 threads and it felt better though still faulted, so moved it out to 14. Powered up the hill twice without fault and thought it was sorted, but the 3rd run it faulted again :mad:. I have carried out Sierafery's tests and reported below.

Cheers

Pete
 
sierrafery said:
Do two tests:
1. drive it with MAF unlugged
2. remove fuse F2 engine bayand drive it like that
then report the results
Click to expand...
Hi,
Thanks for your time. As replied to Stanleysteamer I have been up and down my test hill constantly (fairly steep, 5th gear 45-50 mph, just under 2000 rpm, stutters and loses power ¾ of the way up) this morning.
Having carried out the actuator adjustments without joy, I moved it back to 12 threads and carried out both of your tests. And the symptoms were exactly the same, with MAF unplugged and then F2 fuse removed (not at the same time) the disco was much worse and stutted and lost power before hitting the hill.
Cheers
Pete
 
berg450 said:
Have you checked live data to see what max turbo pressure you have? I also have stage 1 remap but my wastegate had to be adjusted to 11-12 thread to achieve about 235kPa and no overboost. But in your case maybe even the 12 is too short... it can vary as the parts (actuator and even the turbo) are not exactly the same.
Click to expand...

No I don't have the capability to read live data. May link this thread to my local garage and get them to pick up the baton from here, but I definitely think we are on to the problem with the turbo properties mentioned.
Cheers
Pete
 
Update for anyone following this.
I've given up. The symptoms make no sense.
I've just learnt to drive it in high-ish revs (over 2000 rpm), and only go to 5th if cruising or downhill, and it never faults!
Discos :rolleyes:
 
kasapeky said:
Update for anyone following this.
I've given up. The symptoms make no sense.
I've just learnt to drive it in high-ish revs (over 2000 rpm), and only go to 5th if cruising or downhill, and it never faults!
Discos :rolleyes:
Click to expand...
Can't remember, but have you changed the actuator and/or tubes running to it?
 
kasapeky said:
Update for anyone following this.
I've given up. The symptoms make no sense.
I've just learnt to drive it in high-ish revs (over 2000 rpm), and only go to 5th if cruising or downhill, and it never faults!
Discos :rolleyes:
Click to expand...
Just reread the thread and realised you had checked out the wastegate, but not the actuator. So could still be the faults there as mentioned previously.
I am not sure about this but I have a funny feeling we accidentally found out, (we being SF and I) that the IAP/IAT could have unexpected effects on how a Disco runs. Have you at least taken this out and cleaned it? If not changed it?
And finally I would never expect a car of any type, never mind one as heavy as a Disco, to climb a hill in 5th. I know my Discos wouldn't, neither the TD5 auto, which would simply just change down, nor my 300tdi, which is slightly tuned.
Anyway, whatever, best of luck with it all.:)
 
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