D40 Low boost and comes randomly

_jackjc_ · May 3, 2021

Yeh that's the way it is, I checked when I fitted the new one as it had been plumbed wrong in the past by someone.

Could it be a worn actuator? It's on 104k miles, I've Had vacuum straight to the actuator bypassing the solenoid and it boosted strong, enough to blow the turbo to intercooler hose off

Cpeaco · May 3, 2021

_jackjc_ said:
Yeh that's the way it is, I checked when I fitted the new one as it had been plumbed wrong in the past by someone.

Could it be a worn actuator? It's on 104k miles, I've Had vacuum straight to the actuator bypassing

Better to disconnect the turbo actuator and make sure the turbo control lever is moving freely, VNT turbos can have issues with the control ring sticking due to carbon build up inside the turbo exhaust housing, This sometimes causes the ecu to but the system into limp home mode.

_jackjc_ · May 3, 2021

Cpeaco said:
Better to disconnect the turbo actuator and make sure the turbo control lever is moving freely, VNT turbos can have issues with the control ring sticking due to carbon build up inside the turbo exhaust housing, This sometimes causes the ecu to but the system into limp home mode.

I'll have a look into that, although it does move freely under vacuum from the actuator when idling, as above I have had the hose off the actuator and seen the rod move and when re attached it moves back up again

Cpeaco · May 3, 2021

_jackjc_ said:
I'll have a look into that, although it does move freely under vacuum from the actuator when idling, as above I have had the hose off the actuator and seen the rod move and when re attached it moves back up again

If you put direct vacuum on and off the actuator and the lever moving ok it should be ok, Also better to do a EGR bypass on your Truck, Also remove the turbo intake hose and check the impeller is spinning ok and there’s no excess lift on the shaft.

_jackjc_ · May 4, 2021

All done. I've also replaced the hot pipe with an ally pipe and fresh silicone connectors and clamps.
Could the actuator be at fault?

Cpeaco · May 4, 2021

_jackjc_ said:
All done. I've also replaced the hot pipe with an ally pipe and fresh silicone connectors and clamps.
Could the actuator be at fault?

The actuator is strait forward to check it only a diaphragm and return spring. Just connect a vacuum feed direct from the vacuum pump and connect and disconnect the pipe and it should operate back and fore, Some garages use a hand operated vacuum pump to test it, The top end diagnostic scanners will operate the actuator from actuations.

_jackjc_ · May 4, 2021

Ahh okay, well it's definitely not the actuator then as I've carried that test out and seen the correct results. I'm abit lost now really, all the obvious things have been done but I'm still having issues

_jackjc_ · May 4, 2021

Ahh okay, well it's definitely not the actuator then as I've carried that test out and seen the correct results. I'm abit lost now really, all the obvious things have been done but I'm still having issues

Cpeaco · May 4, 2021

_jackjc_ said:
Ahh okay, well it's definitely not the actuator then as I've carried that test out and seen the correct results. I'm abit lost now really, all the obvious things have been done but I'm still having issues

Have you checked for fault codes on your vehicle, I take it the fuel filter and air filter are all ok,

_jackjc_ · May 4, 2021

Yeh I did a check the other day and had faults for the MAF (replacement fitted), brake circuit and overboosting (vacuum straight to actuator to test)
Fuel filter was changed a few days ago and the air filter was done in January

Cpeaco · May 4, 2021

_jackjc_ said:
Yeh I did a check the other day and had faults for the MAF (replacement fitted), brake circuit and overboosting (vacuum straight to actuator to test)
Fuel filter was changed a few days ago and the air filter was done in January

Another common fault on the D40 is the fuel pump s.c.v they can be faulty with no fault codes showing up.

_jackjc_ · May 4, 2021

Is there anyway of testing this before I go buy a new one?

Cpeaco · May 4, 2021

_jackjc_ said:
Is there anyway of testing this before I go buy a new one?

Seen some vids on YouTube they remove the s.c.v and clean it out they can draw in water if the fuel filter not changed regularly sometimes it’s just a temp repair might be worth a try.

_jackjc_ · May 5, 2021

I'll give it a go and see what happens, fingers crossed it solves the issue. Cheers for your help

Cpeaco · May 5, 2021

Cpeaco said:
If you put direct vacuum on and off the actuator and the lever moving ok it should be ok, Also better to do a EGR bypass on your Truck, Also remove the turbo intake hose and check the impeller is spinning ok and there’s no excess lift on the shaft.

Ok, m8 Cheers.

navara30 · May 20, 2021

_jackjc_ said:
I'll give it a go and see what happens, fingers crossed it solves the issue. Cheers for your help

Hi have you resolved the issue my truck is doing the same thing

_jackjc_ · May 20, 2021

Still having issues. So far this is what I have done.

New boost control solenoid X2
Fuel filter
Fuel system clean
Oil and filter
Maf clean
Maf swap
Ally hot pipe and new hoses and clamps
New manifold gasket
Remove and clean suction control valve and flip 180°
Remove and clean throttle body
Remove and clean boast sensor on intercooler
New fuel pressure release valve

ECU hard reset, removing battery etc

Only fitted the pressure relief valve this morning so haven't had proper chance to test this yet.

If it's still not right after that I will be looking to swap out the SCV for a new unit

jerome4506 · Nov 3, 2021

_jackjc_ said:
Still having issues. So far this is what I have done.

New boost control solenoid X2
Fuel filter
Fuel system clean
Oil and filter
Maf clean
Maf swap
Ally hot pipe and new hoses and clamps
New manifold gasket
Remove and clean suction control valve and flip 180°
Remove and clean throttle body
Remove and clean boast sensor on intercooler
New fuel pressure release valve

ECU hard reset, removing battery etc

Only fitted the pressure relief valve this morning so haven't had proper chance to test this yet.

If it's still not right after that I will be looking to swap out the SCV for a new unit

How did you go I'm having the same problem

_jackjc_ said:
Still having issues. So far this is what I have done.

New boost control solenoid X2
Fuel filter
Fuel system clean
Oil and filter
Maf clean
Maf swap
Ally hot pipe and new hoses and clamps
New manifold gasket
Remove and clean suction control valve and flip 180°
Remove and clean throttle body
Remove and clean boast sensor on intercooler
New fuel pressure release valve

ECU hard reset, removing battery etc

Only fitted the pressure relief valve this morning so haven't had proper chance to test this yet.

If it's still not right after that I will be looking to swap out the SCV for a new unit

How did you go I'm having the same problem

D40 Low boost and comes randomly

_jackjc_

Cpeaco

_jackjc_

Cpeaco

_jackjc_

Cpeaco

_jackjc_

_jackjc_

Cpeaco

_jackjc_

Cpeaco

_jackjc_

Cpeaco

_jackjc_

Cpeaco

navara30

_jackjc_

jerome4506

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