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Discussion Starter · #1 ·
Hey guys

My d40 2.5 dt is having some boost issues and after 2 mechanics and a auto sparky later I still haven't got an answer... please help

Boost peaks to 20ish psi and then drops to between 3 and 5...

Replaced
boost controller
actuator
Vacum lines
Fuel filter (nissan)
Cleaned maf sensor
No error codes
Ecu reset

I have a Bluetooth odb2 sensor .
I have noticed the fuel rail pressure drop at the same time the boost lets go. Not sure if that relevant
Next I have a fuel pressure release valve coming and a egr blank..
Ant thoughts as just throwing parts at it dosent seem like a great way to fix this.
 

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You are certainly replacing the rings that cause the most common issues.

Is the turbo actuator pulsing at idle by the way?
 

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Discussion Starter · #3 ·
You are certainly replacing the rings that cause the most common issues.

Is the turbo actuator pulsing at idle by the way?
On idle it dosent pulse, but removing the vacum hose it moves. .
The actuator is brand new as is the vacum hose.
Do I need to have some one in tje car on idle to give a bit of gas to confirm if the actuator is pulsing?
 

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Discussion Starter · #4 ·
B b b
On idle it dosent pulse, but removing the vacum hose it moves. .
The actuator is brand new as is the vacum hose.
Do I need to have some one in tje car on idle to give a bit of gas to confirm if the actuator is pulsing?
And the boost controller is brand new as well ( nissan genuine as well
On idle it dosent pulse, but removing the vacum hose it moves. .
The actuator is brand new as is the vacum hose.
Do I need to have some one in tje car on idle to give a bit of gas to confirm if the actuator is pulsing?
 

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It definitely should pulse at idle.

It is possible you are not getting vacuum, not unknown for there to be a leak over near the brake servo.

Have a read

 

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Discussion Starter · #6 ·
B b b

And the boost controller is brand new as well ( nissan genuine as well
It definitely should pulse at idle.

It is possible you are not getting vacuum, not unknown for there to be a leak over near the brake servo.

Have a read

Ok I will double check, but this is one of the replaced parts (nissan part) .
So on normal idle the actuator should be moving?
It definitely moves when I remove the hose from the boost controller to the actuator and then replace it..
I have also replace that hose as well. Could it still be crimping?
 

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Discussion Starter · #7 ·
It definitely should pulse at idle.

It is possible you are not getting vacuum, not unknown for there to be a leak over near the brake servo.

Have a read

Ok thank you. You would think the mechanic would have mentioned the fact the actuator was not moving at idle after replacing it.... seen another article in here with the actuator not moving and it was the boost sensor map (after the intercooler).
I will double check it again today. Thanks again
 

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Discussion Starter · #8 ·
To confirm. The acutator moves up initally when the car is started.
It then remains still at idle. Even with a bit of reving.
Then when the car is turned off, it drops back to the original position.
The vacum hose from the right hand side of the engine has been replaced.
Not sure if this is relevant I also disconnected the map sensor this morning, it didnt error until reconnected. P0237 low input.
I have cleared the code for now.
 

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The actuator pulses about once per second at idle. First check is to double check all the pipes are on the right ports on the BCS.
 

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Discussion Starter · #10 ·
Also accours the torque app, the duel rail pressure drops at the same time as the boost drops.
Is this expected behaviour or could this be releated to an issue?
 

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Discussion Starter · #14 ·
Hey Landmannn
I placed the vacum hose from the right and side direct to the actuator ( bypassing boost controller completely) to see if that would get tje actuator moving on idle. It didnt.
But after going for a drive the boost didn't drop once. Travelled about 80kms this evening and it run fine.
The boost controller was replaced as was the actuator but I dont get why running it direct it works ok but not though the boost controller.
What is the impact of leaving it like this? Ant thought to why this could occur. Could the ecu map be be corrupt?
 

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The link a few posts above provides some detail, but by bypassing the BCS you are setting the variable vane turbo on maximum all the time.
So on full, you will get turbo lag and worse fuel consumption, it shouldn't do any harm in the short term.

It would be worth checking the voltage on the BCS plug, you should be getting pulses at idle.
 

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Discussion Starter · #16 ·
Thanks for all the help here. I took it to nisssn and within the hour they concluded the arm length on the acuator was incorrect. They spend two hours labour on it and were able to reset the length correctly. She goes great now. Boost peaks and holds, no drop :)
So the conclusion here was the orginal acutator had a fault, but when the local mechanic replaced the acuator the arm length was not correct ( this wasn't a nissan actuator as nissan dont sell seperate).
 
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