Both actuators are free and cycle through the full travel.

Car is a little better in sport mode / command shift as the revs are higher.

Fuel filter changed no more than a month ago

Go back to basics as there are no codes, get a compression test done, if a foreign object bent or damaged valves or their seats or rings etc. lack of compression would give a lazy throttle and performance unit the turbos ramp up enough boost to mask the lack of compression

Did you use a genuine LR fuel filter as some after market ones have been known to cause issues? Current 2007 TDV8 Vogue Buckingham Blue

Maybe your mechanic was on the money with the other turbo not working properly, but with sticky vanes rather than a sticky actuator linkage. However I still wouldn't expect such a lack of low down performance then a dramatic increase at a particular higher rpm.

Maybe try a genuine fuel filter (if an after market one was fitted), but this is starting to sound like a tin brain to me. You mentioned earlier that you’d had the EGRs blanked and re mapped. Are you able to have this rechecked?

I doubt it’s a turbo or a compression issue if the engine spoils up eventually.

When my nearside turbo actuator (which controls the variable vanes) seized, she was lethargic throughout the rev range.

Are you able to measure boost pressure with your code reader?

I can’t quite remember if the vanes stall the air flow at low revs or high revs. Meaning if the actuator is functional, but disconnected from the vanes internally, this may cause your issue by not supplying enough air at lower revs. Having said that, you’d probably have an alarm.

Are you losing oil? Not externally, I mean oil on dipstick going down but no obvious leaks. (A little oil in the driver side turbo air pipe is normal) 2007 3.6 TDV8

The vanes are moved to increase turbo speed when exhaust gas flow is low then re-angled to have less effect as exhaust gas flow increases.

One other thing.

Could to try to view both the actuators function whilst revving the engine in Park.

I’m also wondering if the hose failure was caused by the n/s actuator not functioning correctly. 2007 3.6 TDV8

I’m wondering if the vanes are stuck in the full load position, so at low load the turbo is unable to spool up, but I’d assume there’s be some alarms to suggest a disturbance in the force.

Maybe caused by the ECM (position 1)

Click image to enlarge

Have the MAF live values been compared? If the left turbo is performing poorly at low engine revs then the MAFs would read differently. The MAP sensors would be pretty much identical if the I/C is a combined unit rather than have a separate section for each turbo.

Edit. Re-reading revealed the comments below which seem contradictory because if 1 turbo had a sticking actuator then the turbo would be performing differently and showing-up in differing MAF readings.

Had a specialist check out the car. MAF readings all normal so that can be disregarded in the diagnosis.

The specialist has driven the car and reckons the turbo actuator is sticking on the passenger side.

Hi Graeme,

The specialist said that one maf will always read differently to the other. I was sceptical of this but I think I trusted in his explaination as he is a 'specialist'

Maf 1 which connects to the o/s turbo reads lower than maf 2 which connects to the n/s turbo.

o/s turbo was the one replaced.

Would I be correct in thinking that stuck variable vanes would cause error codes as the actuator wouldn't be able to reach the requested value?

I would expect the actuator not to move its full swing if the vanes were stuck and therefore expect a fault to be recorded unless the connection to the vane mechanism was damaged allowing the actuator to move as expected. However it would be a real co-incidence for such damage to occur at the same time as the split hose.

I can understand that the right MAF would read slightly lower than the left due to the engine breather connection between the MAF and the turbo. However I can't reconcile that the specialist considered the MAF readings are normal yet thought that the left actuator was stuck if the MAF values were recorded during the same session unless he thought the stickiness was very short duration and not the cause of the prolonged poor performance.

It is my understanding that on the 3.6 TDV8 the two banks are fed by effectively separate induction systems with only minimal connection between them. There is no truly common induction plenum. Which is why the system checks correlation between boost pressure delivered and boost pressure expected on each bank and can isolate each one in error codes.
The really odd thing about this problem is the lack of any error codes. Previously a 2008MY Tonga Green Vogue SE 3.6 TDV8

Maybe we are focusing too much on the engine? Might there be a gearbox-related aspect? Could the fluctuating idle be TC related and the lack of acceleration be a problem with the comms between the gearbox and ECU? Gearbox problems wouldn't show up as error codes.
My car certainly, in the past, would seem sluggish and slow to get going even with foot well down. Previously a 2008MY Tonga Green Vogue SE 3.6 TDV8

Nick, that’s how I’ve interpreted it as well.

Lack of codes is odd but when one of my hoses split I didn’t get any alarms, so I guess, reliance on alarms isn’t a given.

If the OP could rev the engine in park and verify the actuators move the same travel, that would be a starting point. Monitoring the boost pressures whilst “flooring it” would be handy.

Or, spend an hours labour at a dealer to fault find.

I have had experience of mis diagnosis from “specialists”, but have had 100% success at my dealer when I’ve hit a brick wall.

My guess is the passenger side actuator not fully travelling back to “closed” hence the lethargy at lower revs. 2007 3.6 TDV8

Nick,

Not saying it couldn't be a gearbox problem but I didnt have any issues with the gearbox at all it was perfect up to the hose splitting. I feel it would be a coincidence for it to have failed at the same time as the hose. I feel the problem is engine related and may be causing glitches in the box because of the wrong signals being sent if that makes sense?

I think a good thing to do would be a screen recording of SDD showing boost pressure, maf, speed, throttle position etc and then post it for you guys to have a look at. See if anything sticks out?

I am going to ask the specialist if he can book it in