How to check turbo actuator on V9X engine?

[Labsy]

Hi,

I have 2010 with 3.0 V9X engine. Turbo is squeezed nearly into dashboard and have problems checking, if turbo actuator rod is moving those variable vains. Is it possible to check it without tearing apart half of the vehicle?

STORY BEHIND: Vehicle is acting weird when driving on curvy roads, especially uphill. When approaching curve, I let off gas pedal alightly and it shifts up, letting revs down to 1000-1200, and when I need some power to pull me out of the curve, slightly adding gas pedal does nothing at all. My wife says: Should I get out and push a little?
Only way to overcome is to literaly floor it, but in this case it has lag to shift down 2 gears, revs up and pulls brutally, so on slippery road it slips and wanders like crazy.

I guess it must be also some turbo controll issue, so I would like to check if actuator really moves the rod.
BTW... I checked vacuum, no leaks.

Thanx.

 

[Old.Tony]

It would be easier (and will provide you with more information for all of the car's systems) if you grabbed Bluetooth ELM327 OBD adapter and an app like Android Torque. Monitor the boost levels - if the intake manifold pressure rises as expected, the turbo is working.

I do not recommend asking the wife to sit in the engine bay and use her makeup mirror to view the actuator arm while you're driving, because driving with the bonnet up is not safe! However, if she wants to push the car, it will save you fuel so you might consider that too.

 

[Labsy]

Well, regarding OBD monitoring...I tried it, but could not find proper sensor. Maybe just app was wrong, as Manifold Boose Pressure shows constant 100 psi, even after I shut down the engine, so I guess it might be measuring my wife's decibel levels when riding open hooded engine bay

So far I found bad Turbo Solenoid Valve and am waiting for replacement to come. But now I am thinking also about Turbo Boost sensor...hmmm, lemme try some other apps before jumping to conclusion.

thanx for tips

 

[Olpha]

Hi Labsy
I think you will be right with the boost control solenoid
You may be noticing it sounding a little more drummy at idle and it seems to have poor pulling until it gets closer to 2k revs
You can bypass the BCS by butt joining the vacuum hoses in order to test ONLY while it is idling
You will likely hear the engine note change when you do it
I have never been able to pick up anything on my scan tool either but this simple test proved heaps for me
Unfortunately the BCS is a common issue on this motor
Incidentally, mine is going a hell of a lot better with an upgraded intercooler as well

 

[YCJCYASATB]

Hi Labsy.
I have the Pathfinder with the same engine. I find this is exactly how mine has always performed. I bought mine second hand, so cannot say if it’s normal. I recently had my BCS replaced as I was leaving a smoke screen behind me that James Bond would be happy with. Plus having intermittent power delivery and that LDV’s would pull 3 car lengths on me by the time I got to 60km/h. I have good power again with much reduced smoke. But the engine will still try and hold 5th gear at just over 60km/h going up hill and needs almost full throttle before it decides that 2 lower gears are required and takes off like a scalded cat. I then reduce throttle input to retain my license and it changes back to 5th and I have the same exercise again. My vehicle will do this over and over again if I can find a long enough hill. I find I have to manually select 4th.

I have always believed it was the way the engine and transmission had been tuned from factory. Always seeming to get into the highest gear possible. Perhaps this is normal or perhaps you and I have a very similar issue?

Evan.

 

[Labsy]

@Olpha, thank you, I purchased new one and hardly awaiting courier now.

@YCJCYASATB, yes, exactly the same issue with transmisson!
What I read in Service Manual, it is a feature of this 7-speed transmission to have clutch-lock in 4th, 5th and 7th gears only, and TCM will try to keep one of those gears as long as possible. Decision to shift down is made on numerous parameters, among which are also:
- turbo parameters, like manifold air pressure and turbo vacuum from BCV (I think it has dual function - it can restrict vacuum to turbo actuator AND also informs ECU back on vacuum from turbo, but I am not 100% sure whether this is true or not) --> so maybe this tiny BCV is important influencer for TCM decisions?
- G-sensor parameters, like to not change gears in the middle of the curve, and to shift down when going uphill and such, so...--> it might be, as I leveled it up and installed 2,5'' lifted suspension, G-sensor needs to be recalibrated, which can only be done with Consult 3.

Maybe helping workaround: when I drive uphill and approaching some curve, I learned to slightly kick gas pedal right before braking, so tranny shifth down and with some exercise I manage to attack the curve with revs around 2000, turbo ready and will have just the right torque and power to drive a shade more sporty. Sport mode helps a bit, too.

 

[Labsy]

Well, today I replaced BCS with new OEM one and the issue remains:
When I floor it I get P0235 code and car drops to partial limp mode. By partial I mean I can still drive 120 km/h and in low revs it still pulls, but is kinda dull. Also turbo is noticeably louder, humming and when off the gass, it sounds like ill dinosaur exhaling.

Now, on my V6 V9X engine turbo actuator is not visible. I will check again later when it stops pouring (damn April weather...)

What I am thunking... Torque shows 15psi in idle and up to 40-something, even up to 50psi when full boost under load.... might it be due to Chiptunning?
Nevermind...will gather some fuel rail pressure and came back annoying you

UPDATE:
Seems like parformace has come back, despite of P0235 code, which is still present. I did some power driving with one eye on road and another on ODBII app and I found that measurable parameters are quite within expected. See yellow markers of MIN and MAX values, look normal to me:
- MAP pressure up to 37 psi (minus initial 14,7 = some 22 psi of additional boost) NOTE: Before I changed BCS solenoid today, I had up to 50 psi!
- Fuel Rail Pressure up to 1800 bar
Those two also go one with another when giving it some juice...
...except in low RPM, around 1200-1500 rpm, where both MAP pressure and fuel pressure raise up, but all it gives is octopus effect for vehicles behind me.

 

[Labsy]

UPDATE2: if anybody interested, even on V9X machine you can see turbo actuator rod moving.

In my case when vacuum hose is connected and engine is idling, vacuum pulls actuator rod towards front of the engine some 2cm. And I can hear turbo whistling slightly.
When vacuum is disconnected, actuator moves back to where it sits when engine is shut off. And Turbo whistling stops.

I made a short video on the subject:

 

[Labsy]

It would be easier (and will provide you with more information for all of the car's systems) if you grabbed Bluetooth ELM327 OBD adapter and an app like Android Torque. Monitor the boost levels - if the intake manifold pressure rises as expected, the turbo is working.

Hi Tony,

I am still struggling with the issue - when I give it some juice, vehicle falls into limp mode, throwing P0235 code. I can drive whole day, even faster like 130 on highway, but if I do not exagerate on gas pedal, it will be fine, But as soon as I push it under load, especially in low revs to black smoke, limp mode kicks in with above code.

What I found in manual, what's the logic behind this code P0235. At least one of these must be true:

1. ECM detects open circuit of turbocharger boost sensor circuit for 0.4 second or more.
2. ECM detects short circuit to power supply of turbocharger boost sensor circuit for 0.4 second or more.
3. ECM detects short circuit to ground of turbochargerboost sensor circuit for 0.4 second or more.
4. Difference of turbocharger boost sensor value and barometric pressure sensor value is 160 hPa or less for 2 seconds or more when ignition switch ON.
5. Difference of turbocharger boost sensor value and barometric pressure sensor value is 200 hPa or less for 10 seconds or more while running the engine at idle speed

In my case (1), (2) and (3) simply cannot be true, because code does not trigger when idling or standstil, even not with light driving. (4) is talking about comparing barometric pressure when engine is not runing, only ingition swithc is ON, to this rules it out, and (5) says at idle speed, which also does not apply in my case.

Might it be loads of oil in intercooler, messing with turbo boost sensor?
Or chiptuning...but this was done 1 year ago and no problems until now.

BTW... after all my tests with turbo actuator rod and replacing Boost Solenoid Valve, turbo exhaling is noticeably louder. Almost like there was no air filter, it is so loud...but maybe it is how it supposed to sound?

Need some brainstorming...ideas welcome.

 

[Old.Tony]

I'd carefully look at the wiring loom for the boost sensor and make sure it's not damaged at all. I'd also make sure the base of the boost sensor has a good connection to earth (battery negative). I'd probably test that with a multimeter, but I suspect that whatever is causing this is doing it when engine demand is high, so the torque is twisting the engine and pulling a cable or connection apart causing the error.

A really simple test would be to connect a temporary wire (with a reasonable amount of extra cable to allow for movement) from battery negative to the base of the sensor (or any metal framework around it) and drive the car.

 

[Labsy]

Good point! I am grabbing new Turbo Pressure sensor and will install it tomorrow, examining whole presurized system for leaks best I can do without smoke detector. Maybe I burn some indian smelly sticks Regarding loom...yes, it might be damaged, as it was messed with many times. I'll go by the manual and wheck conductivity, possible damages etc... Thanx for idea!

 

[Olpha]

Hi Labsy,
There are so many inputs that this system uses to achieve one outcome (read gear change or more boost) that it can be very hard to find the exact issue.
Given the code that you are getting (P0235) I would be thinking points 4 or 5 (of the manual) as I understand it is only happening after you get on the road. Points 1,2,3 would happen at idle or even on prestart diagnostic checking. Further to that, Point 5 indicates that situation is at idle only. This is then pointing to a possible problem with the boost pressure sensor OR your intercooler leaking badly/blocked enough to restrict the correct volume of flow.
I too would be checking the boost hoses. Particularly on the cold side. I popped one recently down near the battery and I could not detect it until I took it completely off and flexed it around. No discernible air noise and no oil smear, just sluggish at medium revs and slow gear changes.
My understanding is that the Barometric sensor is built into the ECM. Is there a possibility of any damage or dust/water affecting the input connection?
Maybe burning the smelly sticks will let it know you are getting really bloody serious and it is time to stop mucking around

 

[Labsy]

Well, I did something in past few days, mostly waiting for the rain to stop pouring on my disassembled vehicle

I took intercooler off, dismantling whole front before that, and found out Turbo Boost sensor was mechanically broken and re-installed with a lot of sealant. Same with inlet and outlet pipes on intercooler, all were full of sealant.
Took everything apart, cleaned all hoses, refurbished gaskets, cleaned intercooler with kerosine and with few bottles of brake cleaner afterwards to get rid of kerosine smell. Tested for leaks and it is OK. Put new Turbo Boost pressure sensor, changed engine oil and all filters...

Today I took it for test drive and it goes fine...until a loud explosion was heard and I thought one of turbo pipes blew. But no, it was the last rubber hose from intercooler, which connects to throttle intake - clamp did not hold the pressure. Replaced with new (cheap one) clamp, but it flew right away again.

So, obviously there are no leaks, I just need to provide some proper clamp on throttle body intake.

BTW...Pressure was around 45 psi total, taking in account normal atmosferic 15 psi, it means some 30 psi of additional boost. Which translates to 2 bars!!! Isn't this a bit high? No wonder clamp failed...

 

[Olpha]

Good to see you are getting there Labsy.
30 psi is a figure I have seen promoted before and mine is coming in at about the same on electronic monitoring. I will be installing a manual gauge soon because I don't necessarily trust the accuracy or response of electronic monitoring.
I take it from what you said above that the Turbo Boost sensor was not able to do its job and the electronic values were out of parameters, hence bringing up the code. If that is the case it does give some confidence in the Nissan manual diagnostics. It also reinforces the old adage that the problems are usually quite simple but not necessarily easy to find.

 

[Labsy]

Well...project suceeded, but patient still sick

Hose at throttle intake still does not want to stay on, so I bought the freakin' plumbers clamp, but this felt off, too. I figured it out this roboust clamp is too wide and it does not lock rubber hose into the ridge:

So I added some elbow grease and made it thinner, that'll do, for sure:

But no...hahaha, almost Mr. Bean project - that thinner one felt right into the groove, but it was clamp's end circumvence, so it did not clamp enough, so I added an arc out of another clamp and forced it under the main clamp. Ou yeah, that clamped like a pitbull:

Project "Clamp" finally finished, me happy...
...but after all that has been done, hose does not pop-out anymore, but P0235 DTC does. As soon as I push it for more than 5 seconds...here it goes into limp mode and P0235 pops up again.

What's wrong with you, my dear Pathy?

 

[Old.Tony]

Did you replace the boost sensor with a new one, or did you just reinstall the old one?

30psi is high but not impossible for the engine. They're supposed to peak at about 24psi but one guy (from the USA?) had his doing about 36psi.

 

[Labsy]

Did you replace the boost sensor with a new one, or did you just reinstall the old one?

I replaced it with new one, Bosch supposedly.

Regarding boost, many others also say that 30 psi of additional boost (15 base + 30 additional = up to 45 total psi) is quite normal.
One of the problems is, that I do not remember exactly how it started with this P0235 DTC one month ago. I was messing something with Vacuum Solenoid Valve, replaced it with new one, then I tested turbo vanes whether they are moving or not (they are), and somewhere during all this I landed on P0235 DTC and limp mode, which I cannot get rid of.

By the end of week I am getting Thinkcar Thinkdiag OBD2 scanner (this one), which can display multiple parameters from ECU, in my case I will be monitoring barometric pressure from ECU and trom turbo sensor, and draw a graph to watch for possible outages. Will see how far will this bring me...

 

[Labsy]

Emmmm... I got my Thinkcar diagnostic device today and left my shift earlier to play with new toy
But vehicle no start, battery died after 2 days of hybernation. Damn, expenses again. It was diying all long winter, ok, need new one sooner or later.
Then went a short pedal to the metal drive with new scanner tool and could not pull any DTC, nor get limp mode to engage.

Damn...could it be poor battery causing all my troubles?

 

[Old.Tony]

Damn...could it be poor battery causing all my troubles?

Usually not the battery, but a connection to the battery could do it, and by replacing the battery the connection was repaired. Easily possible! See if the problem returns over the next few days. We'll still be around, I'm not going anywhere until next Friday.

 

[Labsy]

Update:
No, it was not battery. I also reset TP lerearn and EGR, but still the same.
Went few rounds and hit limp mode and P0235 every time at about same parameters:

RPM: 3250
Fuel rail pressure: 1600 bar
TC boost: 2.4 bar/35 psi (atmosferic pressure deducted already)
Torque: 530 Nm/390 ft lbs

What I suspect is few things:

1. Could it be TC boost simply too high? Vehicle is chiptuned, hmmmm... maybe I should reprogram ECU back to original?

2. On ECU diagnostic graphs I noticed APP accelerator pedal position sensor (red line) looks kinda interrupted. I can see its tiny red spike just at the moment limp mode and P0235 occured. But I guess this is expected.