Other TDV6 2.7 turbo overboost fault

wammers · May 1, 2018

gstuart said:
may i ask were they designed to replace the wastegate type of turbos , also to reduce turbo lag

my over boost will only happen over 50mph or if i boot it , indeed and put my hands up it’s a big learning curve for me

from ur description it sounds like the vanes are sticking at low revs as if i boot it from low down it certainally doesn’t hang about

findings so far is the actuator as i watch it look slightly notchy , maybe the vanes are chocked up with carbon

also the horizontal hose on the left has oil around it, loose jubilee clip which when i tried to tightened wouldn’t because of the worm broken , alas though i don’t know if that’s enough to cause the overboost issue

once i get more covers off and then the hoses will then use a borascope to see if indeed it’s full of carbon, looks as though spraying oven cleaner in there or if it’s indeed better to buy some turbo cleaner and spray it directly in there

will of course update the thread and as always very grateful for the help and expertise

thks

Your problem will be variable vanes sticking. Never done one but access does look a little limited that's for sure.

gstuart · May 1, 2018

wammers said:
Your problem will be variable vanes sticking. Never done one but access does look a little limited that's for sure.

thks, assume that’s maybe why the actuator is notchy as it moves

indeed , regarding access, u can just see the actuator arm in the middle of the pic, has that round ball on the end of it,, won’t know if i’ve got to remove the top wishbones out yet

going to look if i’ve got better access from the top , taking all the battery tray out etc ???

i also looked at the exhaust manifold which i believe is where the vanes are, but those bolts look ready to simply snap , will be in a better position when i get that strut and panels out

gstuart · May 1, 2018

found a better picture of the hose that is leaking

it’s the left horizontal one , the jubilee clip on mine is broke and therefore can see oil around that pipe

don’t know if it would cause the overboost issue but will be replacing that clip as a matter of course and will attempt to replace that short one with a new silicone hose i’ve already got

i may be some time, lol

gstuart · May 1, 2018

also this is what i’ve got to look forward to replacing the hoses and gettting good access to the turbo actuator arm, will then use a borascope so see if i can see what condition the VGT vanes are like

holidaychicken · May 1, 2018

A big fat turbo takes a while to spin up so would lag at low rpm but produces lots of air pressure at high revs which could be too much so instead of a wastegate that just dumps excess air the variable nozzle / geometry / vane directs a lot of exhaust to the hot side turbine at low rpm to help it spin up and then reduces it back as rpm increases to stop you getting too much boost all of which is controlled by the engine ECU, MAP sensor and actuator. The code P0046 can be caused by a split pipe which would imply less boost but also vanes sticking could mean there is a difference between what the EMS asked for and what the MAP sensor found, MAP may be faulty, The MAF knows how much air it is putting into the turbo so again if that’s is unhappy that could also cause errors. That is my understanding anyway.

You posted me a good walk through on how to do the job including drilling out a roll pin which sounds like great fun.

If the internals are similar to Garrett you won’t see the vanes without splitting the turbo but you could see the turbine blades and any excessive lateral movement.

If you have a loose pipe it might be fine at low pressure but as pressure builds it might be ok up to a point and then left out a loud fart for want of a more technical term.

gstuart · May 2, 2018

holidaychicken said:
A big fat turbo takes a while to spin up so would lag at low rpm but produces lots of air pressure at high revs which could be too much so instead of a wastegate that just dumps excess air the variable nozzle / geometry / vane directs a lot of exhaust to the hot side turbine at low rpm to help it spin up and then reduces it back as rpm increases to stop you getting too much boost all of which is controlled by the engine ECU, MAP sensor and actuator. The code P0046 can be caused by a split pipe which would imply less boost but also vanes sticking could mean there is a difference between what the EMS asked for and what the MAP sensor found, MAP may be faulty, The MAF knows how much air it is putting into the turbo so again if that’s is unhappy that could also cause errors. That is my understanding anyway.

You posted me a good walk through on how to do the job including drilling out a roll pin which sounds like great fun.

If the internals are similar to Garrett you won’t see the vanes without splitting the turbo but you could see the turbine blades and any excessive lateral movement.

If you have a loose pipe it might be fine at low pressure but as pressure builds it might be ok up to a point and then left out a loud fart for want of a more technical term.

that’s a great explanation and makes a lot of sense , cheers for that

this is the exact fault code i’m getting

Engine TDV6

P0234-00 (68) Turbo/supercharger overboost condition
- Confirmed
- Test Failed Since Last Clear
- Test Not Completed This Monitoring Cycle

will find out what the MAP readings are and what they should be to ensure 100% that’s all correct as i wish to do this methodically

can’t believe how much i’ve learnt in the last few weeks , can see now how important those vanes are for and indeed makes more sense why limp mode is caused

also came across this video

gstuart · May 2, 2018

forgot i had posted this earlier , now got find out and check the figures against manufacturers

MAP 98.2 Kpa @ 834Rpm or in English 14.2Psi

holidaychicken · May 2, 2018

That basically 1 bar I think as you are at idle , you need to record live data to see what the map does as revs increase
Apologies I thought you had the P0046 code

gstuart · May 2, 2018

holidaychicken said:
That basically 1 bar I think as you are at idle , you need to record live data to see what the map does as revs increase
Apologies I thought you had the P0046 code

thks, will do that this week, is up on axle stands but can still start the engine up and get live data readings

have been trying to search all other forums as well to see what the baseline figures should be for the MAP sensor to no avail

thks again

holidaychicken · May 2, 2018

You really need to drive it to get an idea of whats going on, revving it on the drive with no speed or load probably wont give you the data you are looking for

gstuart · May 2, 2018

holidaychicken said:
You really need to drive it to get an idea of whats going on, revving it on the drive with no speed or load probably wont give you the data you are looking for

no worries and thks, will have to wait till i get all the front suspension finished first , as it’s on the axle stands

will at least be replacing the 2 x turbo intercooler hoses and every day spraying some ceramic penetrating oil on the actuator so it will have plenty of time to soak in

then will indeed give it a good test drive and record the live data and atttach it here

thks again

freelance · May 2, 2018

If it’s driveable, I think I would be adding some dpf cleaner t the fuel and give it an Italian tune up, for a couple of hours on a motorway

Other TDV6 2.7 turbo overboost fault

wammers

No longer with us, RIP

gstuart

D3 Grandad

gstuart

D3 Grandad

gstuart

D3 Grandad

holidaychicken

Well-Known Member

gstuart

D3 Grandad

gstuart

D3 Grandad

holidaychicken

Well-Known Member

gstuart

D3 Grandad

holidaychicken

Well-Known Member

gstuart

D3 Grandad

freelance

Well-Known Member

Similar threads