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Guide to the Boost Control Solenoid

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148K views 58 replies 24 participants last post by  Ma Kerr  
#1 · (Edited by Moderator)
I thought I would share my experiences and hopefully save a few of you some money. This only applies to diesel Navaras and Pathfinders assembled in Spain between 2005 and 2010.

What is the boost control solenoid designed to do?
It regulates the turbo boost pressure, not the same, but similar to what it does to a wastegate on a petrol engine.

Where is it?
Under the airbox next to the alternator

How do I know if it is failing?
You will get the following symptoms:
  • the truck will feel a bit unresponsive; you will probably ignore this because it is gradual.
  • you may occasionally find the truck feels "off the turbo," and you have to change down to get moving
  • you might get some smoke when pulling away from junctions (beware, several other things can cause this too)

How will I know when it has failed?
Fairly obvious when it happens:
  • a big cloud of smoke when pulling away from junctions
  • lack of power, will only get to 60 mph
  • if you have a method of measuring boost (ie, Torque app), you will see almost no boost
  • at idle, the boost lever can be seen to move up and down fairly slowly if it is working, if not working, it will not move at all - see picture, it is the rusy rod underneath the once gold thing on the turbo.


Image


What next?
Two things you can do:
  • buy a new boost solenoid ÂŁ90 from Milners, double that from a dealer
  • clean it. I took it off (see picture) and squirted loads of carb cleaner in the holes the rubber tubes connect to.
You don't need any tools to replace the solenoid, although maybe a small screwdriver would be better used to remove the wire clip securing the electrical plug.
Tip=Make a note of which of the three rubber pipes go where so you can put it back together correctly.
Afterward, you will notice the truck is far more responsive to the throttle and pulls away from junctions more quickly.


Image



Personally, when I cleaned mine, it went back to working perfectly, so I didn't need to part with ÂŁ90 for a new one. Having already bought it, I decided to fit it anyway.
If you like part numbers, this is the box the new one came in from Milneroffroad.

Image


A later post by one of the members shows how to adjust the turbo actuator

 
#48 ·
Hi guys.
Paranoid,that I got the pipes around the wrong way…due to the fact,the boost lever works and goes up n down..now fitted 2 brand new ones..and the leaver does NOT go up n down..
Surely 2 new ones can’t be faulty.
Can someone please advise if I have the pipes the right way? And going to correct places?
Thanks..see pics
 

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#50 ·
A tonne of thanks to the guy who created this post! My Navara was overheating so i had to take it to a mechanic, he suggested me tat radiator and thermostat need to be changed and during service he change few pipes as well, during servicee one of his boys broke the heatr Tee piece which is a **** to fix, so he made a Tee usinng his skills and fixed that part, after collecting my car i started feeling sluggish and spped wont go above 110kph, felt like no kick is coming out of the turbo. started looking for a hint in the internet forums and hit this one by my luck! i started following all the tubes as described using the image in this forum and saw that the tube going into turbo was broken because of excessive pressure on it caused by the new (custom)heater tee, i reconnected the tube, had a thick black smoke come out of exhaust as i revved to 3000 rpm, whole alley was covered with unburnt diesel smoke! I am happy you guys helped me trace the issue! Rock On! Much appreciated!
 
#52 ·
A tonne of thanks to the guy who created this post! My Navara was overheating so i had to take it to a mechanic, he suggested me tat radiator and thermostat need to be changed and during service he change few pipes as well, during servicee one of his boys broke the heatr Tee piece which is a **** to fix, so he made a Tee usinng his skills and fixed that part, after collecting my car i started feeling sluggish and spped wont go above 110kph, felt like no kick is coming out of the turbo. started looking for a hint in the internet forums and hit this one by my luck! i started following all the tubes as described using the image in this forum and saw that the tube going into turbo was broken because of excessive pressure on it caused by the new (custom)heater tee, i reconnected the tube, had a thick black smoke come out of exhaust as i revved to 3000 rpm, whole alley was covered with unburnt diesel smoke! I am happy you guys helped me trace the issue! Rock On! Much appreciated!
Appreciate the feedback.

Actually pretty common to have problems with the vacuum operated turbo vane system. It was improved in 2010 by the way.
 
#54 ·
Anyone had this?
The vaccum is strong in the pipe. But it struggles to pull the actuator rod.
Im thinking broken actuator?
Perhaps stuffed turbo?

(Boost control solenoid has been replaced)
I've got something similar going on. Easy enough to test whether the actuator or turbo is your problem by removing the actuator and testing with a hand-held vac pump. Once removed you can also manually manipulate the lever on the turbo and confirm the vanes are opening and closing easily.

How strong is the vac on your line in? It is helpful to test the vacuum both from the pump to the boost control solenoid and from the BCS to the turbo. I wouldn't recommend removing the actuator unless you have first trouble shot vacuum and BCS and confirmed no issues there.

In my case the actuator would kind of get stuck around the 12 in/hg mark and stop, when by rights the rod should keep pulling up all the way to about 18 - 19in/hg (and hold). If you test while still in the car and the rod does not keep moving up, the problem could yet be a poorly calibrated stop screw. Hence why a bench test is most instructive.

It is not easy finding a genuine actuator, whether new or from a wrecker. I contacted a bunch of places and everyone wanted to sell me a whole new turbo. In the end I ordered this one from China which I expect will arrive in the next week or so, so I cannot tell you yet how good it is.
 
#57 ·
Hey guys I've ordered a cheap vacuum control solenoid for my 2010 Nissan navara it looks the exact same and goes slightly up and down at idle but when I give it revs it drops the waste gate open and let's all the pressure out of the ATM valve is this a faulty solenoid? And could I temporarily block the ATM valve off?