No boost. Why ?

[JamesMac]

Hi Guys Last week I brought a 2007 d40 2.5 common rail st-x. It was leaking fuel and way low on power. In the upper rev range which I assumed was due to the leak and the fact that the vacuum lines were in the wrong places on the boost controller. Anyway. Long story short I have fixed the leak and replaced the vacuum lines with new ones and cleaned the maf, and boost controller. Now it’s still not making boost. I know this because when I pinch the large boost hose coming from the turbo and get someone to floor it the hose sucks in under engine vacuum and doesn’t push my hands apart like you would expect. Now I have tried this with the boost controller connected and also with the vacuum line from the vac pump attached directly to the turbo. The turbo actuator moves freely and the engine exhaust sound changes pitch when the actuator is in the up position. I’m stumped . I plan on taking the intake piping off tomorrow and checking if the turbo blades are actually spinning but I doubt it’s failed it looks brand new.

Am I missing something

Thanks for your help

James

 

[JamesMac]

Anyone got any ideas

 

[TCN]

I would check the turbo first before you start chasing your tail and emptying your wallet as it could be the MAP, BCS, mine was similar and the turbo bearing had seized but i went thru the expensive exercise of replacing map, bcs and scv before checking the actual turbo

 

[MANNING]

... when I pinch the large boost hose coming from the turbo and get someone to floor it...

I was always under the impression that you won't reach anywhere near full boost at idle.. you may get a few PSI but nothing like you will driving.

Have you got a OBDII port reader and an app such as Torque to display boostt levels from the computer?

 

[TCN]

you will get enough boost to at least feel the pressure in the boost hose

 

[Old.Tony]

^ BCS is a common fault with these.

Easy diagnosis (also tests turbo): take the boost line that comes across the top of the motor to the BCS and disconnect it from the BCS. Connect it directly to the turbocharger actuator. Drive the car (but try not to come off the throttle too quickly). If boost is now present and plenty of power, you know:

A) The turbo's good
B) The BCS is shot.

Your choices at this point:

1) Replace the BCS. Going Nissan genuine or cheap eBay hardly matters, a real Nissan one could fail in a month, they're nuisances, but they have the advantage of allowing the ECU to control boost. It's more intuitive than a Dawes or Tillix valve which is purely reactive.

2) Toss the BCS and install either a Dawes or a Tillix valve (similar principles, I have a Tillix valve on mine and will describe that). Vacuum from the pump is tempered by a valve that balances boost generated against an adjustable spring load (so you can tune it). You have to add an outlet to the boost manifold (the hard pipe that comes off the turbocharger just before the baffle). The vacuum hosing all changes dramatically, it's not an easy jump back to a BCS.

 

[JamesMac]

Hey guys thanks for your input. It was the turbo. It looks brand new but won’t turn. Strange but everything on this car is strange. The previous owner I suspect was on drugs working on it. I don’t have a lot of spare cash at the moment so any ideas for a budget friendly replacement turbo would be great.

 

[Old.Tony]

There are four possibilities.

1) Buy a new bearing and seal kit and rebuild yours. One example (you need to communicate with the seller to ensure it fits your specific turbo, the number is on the side of your turbo):

https://www.ebay.com.au/itm/372654891971
2) Turbo off a wreck. Usually the turbo isn't the cause of the wreck, so it's a reasonable assumption that a turbocharger on a wreck was working fairly well at the time. How much more life that turbo had is unknown. How much damage was caused by the hot shutdown of the turbo when the accident occurred is unknown. Simple answer: it might be cheap and it will get you going but you won't know how long it'll last.

3) Chinese turbo off eBay. It'll be a good copy of a Garrett, I know, I have one here as a spare. No, you can't have it, I need the spare! But it will work, it will work properly, and with appropriate care it will last a reasonable amount of time.

4) Honeywell Garrett but not from Nissan - there's a mob in Brisbane who sell genuine turbos for our cars but rather than the $3K+ price tag Nissan put on them, they're under half that. Brand new. Just like a real one (because it IS a real one).

 

[JamesMac]

Thanks tony. I might check out some of the Chinese copy’s. does anyone have any experience with the brand cct or can recommend a decent one from personal experience.

Thanks again for all your help

James

 

[JamesMac]

I brought a cct new replacement one for $650. Seems like a ok deal. I’ll let you know how it goes

 

[TCN]

James I see you are in Perth, if so i got a exchange Garrett from Turbo fix (out near the airport) for 920 bucks they were really good place to deal with, i have read recently some bad feedback on the CCT turbos I think it was on one of the Pathfinder FB groups.
I think he will only accept a like for like exchange so must be a Garrett, i dont think he accepts the chinese ones only Garrett

 

[JamesMac]

Thanks TCN. I appreciate the info. Unfortunately I have already made the purchase so I’ll see how the cct rubbish goes

 

[Ukracer]

Where does the BCS sit?

Is it possible for it to be contaminated with oil if the turbo blows up??

 

[JamesMac]

The boost controller is down near the air box locate the hose that’s attached to the turbo actuator and follow it you will find a valve with 3 hoses coming out of it. That’s the BCS

 

[Old.Tony]

Where does the BCS sit?

Is it possible for it to be contaminated with oil if the turbo blows up??

There's no oil involved in the actuator, so I really doubt that oil would get into the BCS and contaminate it.

However, given that there almost seems an endless supply of odd things in this world ... it's possible for oil (say, from a boost leak on the charge air piping between the turbo and the intercooler) to be sprayed onto the vac hose right where there's a split/crack and the vacuum sucks that oil into the BCS.

If that ever happened I'd be trying to think of which mirror I broke and how many black cats I have to kill because it is supremely unlikely.

The BCS is a common failure point. It might be the high frequency oscillations that do it in (100 cycles per second).

 

[user 50225]

Thanks TCN. I appreciate the info. Unfortunately I have already made the purchase so I’ll see how the cct rubbish goes

Just be aware that CCT warranty is void if you install it yourself (unless you are a qualified mechanic). Not sure of the legality of this.

 

[TCN]

There is a video on youtube that a guy did a cct install on a pathfinder, and i believe he is one of the ones that had dramas with them

 

[Horatius]

Thanks tony. I might check out some of the Chinese copy’s. does anyone have any experience with the brand cct or can recommend a decent one from personal experience.

Thanks again for all your help

James

Know nothing about your particular model car, or that brand of turbo, but in general have seen cheap ebay turbos (<$300) that have lasted hundreds of thousands of km's with no problems, yet others that have worn out in less than 2k kms (huge amount of play with impeller hitting). Guessing the quality control isn't great, you take your chances and hope to be lone of the lucky ones. They do seem to be getting better though.

 

[JamesMac]

Hi guys. I thought I’d give you an update on the cct turbo. It was easy to fit and so far works great. It seems to spool up quickly and delivers smooth power though the lower and middle of the rev range. The power in the upper rev range is ok but not anything to write home about however I imagine that’s also the case with the factory turbo. I have done almost 5000km so far. All long trips putting a 2 ton not very aerodynamic trailer For $650 I’m happy with it so far.