Range Rover td6 limp mode?

Afternoon all

I have yet another issue with my l322. It appears to go into some sort of limp mode when worked hard up hill.
There’s one hill I go up on a dual carriageway and carry about 75mph going onto the hill. Giving the Range Rover everything it’s got it slows down to about 45 then refuses to Rev past 2500rpm or change car. Then feels very rough after the hill has been dealt with. But will Rev and change gear normally again.
Only fault code I have is related to boost pressure.
I also decided to do a leak off test as I have the equipment and the lowest reading I got after 2 minutes was 25ml and the worst was 60ml.
Any ideas of where else to look?

Which code? @109inches

Mark Piercy said:

Which code? @109inches

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Boost pressure regulation 1E30
I’ve checked all the vacuum lines and all are fine. Vanes for the turbo move as I’ve also checked there. New silicone hoses and new vortex style breather and no better.
Also have a smooth running fault.

109inches said:

Boost pressure regulation 1E30
I’ve checked all the vacuum lines and all are fine. Vanes for the turbo move as I’ve also checked there. New silicone hoses and new vortex style breather and no better.
Also have a smooth running fault.

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Is it reprogrammed by any chance?

Mark Piercy said:

Is it reprogrammed by any chance?

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As in remapped or chipped? As far as I know it’s not. It certainly doesn’t behave as if it’s been remapped And there’s nothing plugged into the fuel rail.

Do. You have any diag where you can watch the manifold or bosst pressure respond to throttle movements?

Mark Piercy said:

Do. You have any diag where you can watch the manifold or bosst pressure respond to throttle movements?

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Yes should have mentioned I have diagnostics and fuel rail pressure is about 360 at idle and this climbs with the revs. Air flow also does and so does boost.

the only thing I haven’t been able to test is under load up the hill where it causes the issue as the diagnostics is on a laptop and doesn’t record data. So I can only see whilst stationary or moving slowly.

Try the leakoff test at a higher Rev range. Sometimes a weak Injector will piddle out at higher pressure.
It would be handy to know what the expected fuel rail pressure is compared to actual.
If the turbo vanes are sticking at high temperature as opposed to cold temperatures??

Compare results with a hot and cold engine.
Boost pressures and fuel rail actual and requested.

Had something similar sometime ago on a Peugeot .limp mod on a hill ,turned out to be a blocked dpf ,try some particulate filter cleaner ,Cant hurt.....

TD6 doesn't have a DPF

Henry_b said:

TD6 doesn't have a DPF

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Ah that rules that out...

When did it last have a fuel filter?

freelance said:

When did it last have a fuel filter?

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Just over a year ago so about 8000.

Another point that may help locate the issue is the turbo whistles loudly at 1800 rpm when in a high gear and very light throttle. If I go above this I get no whistling. There appears to be nothing wrong with the turbo I’ve checked it for play.

Mark Piercy said:

Compare results with a hot and cold engine.
Boost pressures and fuel rail actual and requested.

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Done a little test today.
Air mass looks suspicious:
Actual air mass at idle is 696mg/stroke
Target air mass at idle is 424mg/stroke
Target air mass barely changes when stationary and revving however actual air mass increases to 800mg/stroke then at 2000rpm drops back down to 600mg/stroke.

boost pressure matches target and actual.

pre supply fuel pressure is 4.0 bar at idle which drops to 3.5 bar when revved to 3000.
Rail pressure at idle is 317 bar which climbs to 522 bar at 2000rpm and 600 bar at 3000rpm. This matches the rail pressure setting.

current for rail pressure control is 730mA at idle and 930mA at 2000rpm.

rail pressure control valve is at 18% at idle. And 22% at 2000rpm.

boost pressure regulation is 80% at idle and 56% at 2000rpm.
All testing is done with the Range Rover stationary so not under any real load. Out of everything I’m curious about the air mass values.

Is there any oil residue around pipe ends or the intercooler?

Mark Piercy said:

Is there any oil residue around pipe ends or the intercooler?

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No oil residue. Atleast not since I cleaned them when I fitted the silicone hoses about 1500 miles ago

109inches said:

No oil residue. Atleast not since I cleaned them when I fitted the silicone hoses about 1500 miles ago

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Any oil around the turbo joints?
It could be a physical split some where, a dodgy or dirty map sensor,
Split intercooler or sticking vanes on the turbo.

Mark Piercy said:

Any oil around the turbo joints?
It could be a physical split some where, a dodgy or dirty map sensor,
Split intercooler or sticking vanes on the turbo.

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No oil on any of the joints. Engine side of intercooler and radiator covered in oil just wiped it clean to see if it returns. Variable vanes are free I can move the linkage freely. Is there anyway I can prove it’s working when it should do?