D40 issue, plenty of power, just smoking when pressing the go pedal!

[discosrule]

Hi All,

Wondering if you can help with a 2012 D40 (200,000kms) that is blowing black smoke on fast acceleration, it has plenty of power and not showing any other symptoms.

Things done/replaced over the past 2-months (no particular order);
- MAF cleaned.
- Vacuum hoses all checked.
- Injectors replaced.
- Suction Control Value replaced.
- Diesel filter and air filter replaced.
- Inlet manifold cleaned.
- EGR blanked.

Any ideas?

Thx
discosrule.

 

[Old.Tony]

I'd check boost pressures. At 200,000km there's a chance your turbo is stalling (bearings starting to loosen up) or its control gear.

Electric control (actuators) were replaced by Nissan under either a recall or warranty, vacuum ones are painful and consist of several linked components. The usual failure points are the hoses themselves (3m of 3mm vac hose and replace the lot) or the Boost Control Solenoid (BCS) which is located on the intercooler feed pipe near the alternator and has three vac hoses connected to it as well as an electrical connector. The BCS is a common failure, I've had 3 in total and now use a Tilix valve instead.

Your car speaks OBD-2 (EOBD). Grab an ELM327-compliant bluetooth dongle, get the Torque app for Android on your phone and add a boost gauge. It should show boost punching up over 18psi when pushed hard. If the BCS has failed you won't see this. An alternative method of diagnosing a failing BCS is to disconnect the vac hose that comes over from the right hand side of the motor and attach this directly to the turbocharger. Do NOT push the car hard because a small amount of throttle will pull the actuator to fully open and bring the turbocharger up to max speed very quickly (it will overboost and you may pop one of the charge air hoses, I popped the one that attaches to the intake manifold).

 

[rsgooch]

Tony check your catch can see if bypassing it makes any difference.

Sent from my SM-G930F using Tapatalk

 

[discosrule]

Thx Tony.

Electric control (actuators) were replaced by Nissan under either a recall or warranty, vacuum ones are painful and consist of several linked components. The usual failure points are the hoses themselves (3m of 3mm vac hose and replace the lot) or the Boost Control Solenoid (BCS) which is located on the intercooler feed pipe near the alternator and has three vac hoses connected to it as well as an electrical connector. The BCS is a common failure, I've had 3 in total and now use a Tilix valve instead..

BCS was replaced a year ago I believe, but will check, boost seems fine though, see below.

Your car speaks OBD-2 (EOBD). Grab an ELM327-compliant bluetooth dongle, get the Torque app for Android on your phone and add a boost gauge. It should show boost punching up over 18psi when pushed hard. If the BCS has failed you won't see this. An alternative method of diagnosing a failing BCS is to disconnect the vac hose that comes over from the right hand side of the motor and attach this directly to the turbocharger. Do NOT push the car hard because a small amount of throttle will pull the actuator to fully open and bring the turbocharger up to max speed very quickly (it will overboost and you may pop one of the charge air hoses, I popped the one that attaches to the intake manifold).

Ran that app and it was peaking about 18/19psi when driving hard.

As mentioned I’m not noticing any loss of power, just has a brief puff of smoke when you accelerate hard. Enough that someone has reported it to the EPA once already

-- update --
Here is a chart of turbo boost, just click on the legend to disable/enable the axis you want to see.

https://cloud.highcharts.com/show/HygoFgHfQ

thx

 

[Old.Tony]

I don't think your turbo is boosting quickly enough. At point 39 on the graph, for instance, your engine load is 90%, RPM is 4269 (high!) and boost pressure is just 13.3psi. Yes, you're getting peaks of 18-19psi, but it's taking an awful lot to get there. Even with my Tilix valve dampened to reduce boost, I'm getting 18psi below 2,000rpm. Your engine should be able to reach full boost at 1,800rpm where it's supposed to reach its peak torque.

The vacuum operated BCS is garbage. I hate the bloody thing. If you have a mate with one of these cars, borrow his BCS and see if that makes a difference - if it does, I recommend considering a Dawes or a Tilix valve to replace the BCS. You won't get the ECU trying to control the boost, so there might be occasions when your boost levels don't go the way you might be used to, but it will not fail on you. You can adjust the Tilix valve to come on a little quicker (if you get the secondary valve kit, it's only a tiny bit more $ for it) and you can adjust the peak boost.

A small puff of black smoke on takeoff isn't ordinarily a concern - diesels do it. But if it's significant, then your turbo is probably not getting up to speed quickly enough. Usually that's BCS, but sometimes (it has for me) it's the turbo itself.

FWIW, I'm on turbo #4, 300,000km on the clock. Turbo #3 was NOT bad, it was misdiagnosed as bad, so it's now a "good spare". But the original let go its bearings, and so did the second one I bought.

 

[tweak'e]

i would check for a boost leak.

also reset the fuel learning, especially if you have changed the fuel filter.

 

[discosrule]

> BCS

I will investigate a bit more, might pull it out and see if it is working but at idle I can see the boost lever on the turbo moving up and down slowly.

> reset the fuel learning

done multiple times.



I was just looking at the vacuum hose drawings in the manual and noticed that there are two lines [red square] going from the left to right side, see manual pic below, mine seems to have just the one, is this normal? (will upload photos of engine bay later)

 

[Old.Tony]

> BCS

I will investigate a bit more, might pull it out and see if it is working but at idle I can see the boost lever on the turbo moving up and down slowly.

> reset the fuel learning

done multiple times.



I was just looking at the vacuum hose drawings in the manual and noticed that there are two lines [red square] going from the left to right side, see manual pic below, mine seems to have just the one, is this normal? (will upload photos of engine bay later)

Mine only had one hose too. The little 'Y' junction on the air intake where one of the hoses from the BCS connects along with the second (upper) hose in that drawing had a blanking plug on mine.

 

[discosrule]

Mine only had one hose too. The little 'Y' junction on the air intake where one of the hoses from the BCS connects along with the second (upper) hose in that drawing had a blanking plug on mine.

Ok, thought it looked ok because of the blanking plug.

 

[discosrule]

An alternative method of diagnosing a failing BCS is to disconnect the vac hose that comes over from the right hand side of the motor and attach this directly to the turbocharger. Do NOT push the car hard because a small amount of throttle will pull the actuator to fully open and bring the turbocharger up to max speed very quickly (it will overboost and you may pop one of the charge air hoses, I popped the one that attaches to the intake manifold).

Just going to test this, see attached diagram, red line, is this what you mean for me to try? Just bypass completely.

Might even pull the BCS out follow the instructions in the manual to double check if it has failed, by applying 12v and checking if Air goes thru each port correctly. Doubt this is the problem though as I can see the Turbocharger Boost Control Actuator moving freely when the car is at idle.



Will also replace the vacuum lines. Any easy way to test after that for leaks? Soapy water/vacuum gauge?
And if all that fails, any tests to tell if the turbo is having issues?

Thx.

 

[Old.Tony]

The line in red is correct.

Soapy water won't help because there's nothing in the hoses trying to get out. What I did was to get a small piece of 3mm tube, put it in the end of the suspect hose and suck on the tube. If there's a hole allowing air into the tube, you'll find that you "lose suction".

If you suspect the vacuum control is all good, take the air hose off the front of the turbocharger and with a clean (preferably plastic) rod (like the handle of a plastic fork) give the impeller a prod. It should move (perhaps a little stiffly, but smoothly) without much wobble in the shaft. I've got one in excellent condition here and even though it's been out of the car for a couple of weeks there's no play in the shaft due to lack of oil (I just went down and checked now).

 

[discosrule]

So spent the $9 for 3m of 4mm vac tube from Repco, glad I did as I found the end of the vac tube that attaches to the turbo control actuator to be quite bad, see attached pic, rest of the hoses where In good condition but replaced them anyhow.

Surprised the mechanic didn’t pick it up, even though he said he checked the hoses

One thing I have followed the D40 ECU RESET PROCEDURE in the past with success, but for some reason it isn’t working atm, so pulled the negative power lead for 30mins, hope that resets some of it.

Will report back once I have taken it for a decent drive.

Thx..

 

[Czechmate]

I had to replace all the vac lines on my 07 STX a few years ago

Lost all boost at the bottom of a dip and couldnt get out again

The original rubber lines went ****** when the car had only done about 90,000 ks

Changed em all for silicon tubing from autobarn

Ending up replacing the boost sensor at the same time because the original BCS snapped when i was removing the rubber tubing

The new genuine nissan sensor was slightly different looking and had a different part number to the original
I bought it from a stealership because i was concerned about compatibility and new/old part numbers

Also it made the d40 boost a little earlier and harder