How to check turbo actuator on V9X engine?

[Old.Tony]

I'm not sure the chip was mentioned earlier ... yes, it's always good to take that out of the situation when things go wrong. Try it without the chip.

 

[Labsy]

Update:
Today we restored original ECU maps and get rid of few additional ponies, but issue remains - actually, now I get P0235 and engine goes into limp mode even earlier, right after 2 bars of additional boost (previously it was at around 2,4 bar).

Symptoms are worse every day. Now it is jerky and I can hear turbo hissing in short intervals, can feel all car shaking when I give it slightly too much gas on even slight uphil.

So I narrowed down to:
- maybe clogged or seized catalytic converter? Is it easy to reach on V9X engine?
- worse would be stuck turbo vanes, maybe actuator rod or vacuum actuator, but it is pain to get turbo out on these engines.
- even worse would be one or more innectors.

I am writing all thoughts here to maybe get some ideas, or to help others. It is a bit boresome talking to myself, but it helps me keeping focus.

 

[Old.Tony]

Turbo access on the V9X is not easy, but unless they went for a twin-turbo arrangement, there were not many other good places to put it.

The vanes are usually pretty good, what usually gives up is the actuator - either because the vacuum diaphragm fails, or the vacuum hoses perish, or the solenoid that controls the vacuum fails. Early electronic actuators were subject to a recall by Nissan but these faulty ones may have been only on the YD25 engine.

It's entirely possible that it's a physical wire fault. Here's a video that I found that explains and shows it.

 

[Olpha]

And the worst part about a broken wire is that it could be on any part of the input sensor array. However, given the code displayed it might be a good pointer to start around the back of the motor where all those plugs are.
Can anyone shed a light on what diagnostic program was being used in that video?

 

[Olpha]

Labsy, just a question here. What caused the Boost sensor damage?
Is there any chance there is damage to the wiring further back into the loom?

 

[Old.Tony]

Can anyone shed a light on what diagnostic program was being used in that video?

He calls it a "Thinkdiag". I found one on eBay:

https://www.ebay.com.au/itm/1955774...6820&msclkid=46a87311e78217aaeb9b174ac9eb3b54

 

[Labsy]

Hey,

yes, following the same video I bought it - ThinkDiag. Spent 90 EUR (On Amazon, here) and it's worth it. (...despite menus are hirearchial and you must go over from beginning every time you turn engine off, from car selection, engine, blah, blah...annoying, but you get used to).

I am investigating catalytic converter now, as my mechanic said there are a lot of chances I will find issue there.
But it is a two-part system, one part right after output pipe after turbocharger exhaust, and second one downstream under the vehicle. Later is easily accessible, but the top one, this is pain just like turbo itself. I wich they could make vehicle 5cm longer, adding some space right there, between turbo and cabine firewall

Following excellent advice from this guy here, I will try measure temperature on CAT and reading Oxygen sensors before taking it apart:

• If CAT is working, temperature should increase after CAT. If it is the same or lower than input, then it does nothing or is blocked
• Reading with scan tool, if Oxygen Sensor 2 mimics Sensor 1, then possibly CAT does nothing
• Then driving and on wide open throttle, reading low voltage on Oxy sensors indicates fuel problems (lean mix), while reading higher voltages around 1 Volt, could indicate reach mix, meaning it has problems exhaling

Geez, I am slowly doing dissertation on the subject...

BTW... taking bets - which part of catalytic converter is more likely to get clogged? The inaccessible fakker upstream (1) or easy-to-reach downstreeam one (2)?

 

[Olpha]

Hi Labsy,
The Australian models don't have the 2nd unit fitted so it is only the top unit that you will find.
A couple of years ago I had the opportunity to see a top unit that had been dissected and the design of being long type rods indicated that blockages were unlikely (according to the mechanic who showed me). The owner actually had them removed but told me later that it made no difference to performance that he could tell.
The job of removing the dump pipe is not too difficult but does require patience and a 3/8" socket set. Just be very careful of the O2 sensor. Very delicate. I dropped my dump pipe 50mm when I was taking the motor out and it didn't want to play the game again. $270 later....
I'm starting to feel for you mate, this is a very strange bug that you have acquired and I don't know if there is an antibiotic for it on the shelf
I await the findings with trepidation

 

[Labsy]

Hej Olpha,
thank you for your input. So I have great chances to simply diagnose 2nd unit below vehicle - I will just break the pipe apart just before 2nd unit, let it few centimeters gap and take a test drive. If 2nd unit is blocked, then this should diagnose the problem. Then probably new CAT...maybe straight pipe untill I get hands on some $$$

 

[Labsy]

Damn... few days ago we took the 2nd CAT off, together with muffler, and there was no change. Still turbo like overboosting and P0235 code. Then we changed for the 2nd time SCV Suction Control Valve and it seems to resolve the problem with P0235 code- no DTC since then.

BUT with or without chip, engine seems to have more and more of turbo lag, now it is so extreme that when you try to overtake or give it some without thinking, just by pressing accelerator pedal, it just sits somewhere inbetwwen 1100 and 1400 RPM and generates black smoke. It has never been so bad before.

I took some screenshots of RPM/Boost/fuel pressure and it seems all values go up together just fine...but performance vise it does practically nothing there, just smoking. No DTC. Damn...what's wrong with it?

 

[Old.Tony]

That "second cat" is the DPF - Diesel Particulate Filter. The sensors front and rear of that DPF are known to be problematic - I've replaced mine with some from @auggie (have a read of this post for more info).

I wonder if you're experiencing issues with those sensors? Usually they'd light up the DPF light as well. Do you see the DPF light when turning on your car?

 

[Labsy]

Tony,
I've had problems with DPF last year, went into limp mode and triggered engine light, then I reset it, drove some highway and it was good for a week or two, then again. So after few months of struggle I concluded it is a combination of possibly restricted DPF + chiptuning, so I removed DPF honeycomb and deleted DPF in ECU.
It was OK for maybe half a year, then I begun noticing more and more hesitation when I gave it some gas at low rpm...it simply did not react quickly as before, and also begins smoking. But at higher rpms it pulled brutaly.

So I am still suspicious about how DPF honeycomb was removed... on one side it was nice cut, while on another it was broke and teared. Maybe a piece or two went sideways and block exhaust flow, but as DPF is deleted in ECU, it does not trigger any code?
I guess those sensors before and after DPF do not play any role now?

 

[Old.Tony]

Tony,
I've had problems with DPF last year, went into limp mode and triggered engine light, then I reset it, drove some highway and it was good for a week or two, then again. So after few months of struggle I concluded it is a combination of possibly restricted DPF + chiptuning, so I removed DPF honeycomb and deleted DPF in ECU.
It was OK for maybe half a year, then I begun noticing more and more hesitation when I gave it some gas at low rpm...it simply did not react quickly as before, and also begins smoking. But at higher rpms it pulled brutaly.

So I am still suspicious about how DPF honeycomb was removed... on one side it was nice cut, while on another it was broke and teared. Maybe a piece or two went sideways and block exhaust flow, but as DPF is deleted in ECU, it does not trigger any code?
I guess those sensors before and after DPF do not play any role now?

If you've removed the DPF routines from the ECU, those sensors probably won't be monitored. You could pop the DPF out and check that it's clear, that would answer the "blockage" question.

Reaction time is affected by turbocharger spooling. This could be a worn turbo shaft, a leaking EGR valve or some opening in the exhaust (EGR tube cracked, gasket worn), a turbo actuator not pulling hard enough to open the vanes (usually vac hoses, but sometimes BCS). ALL of these will cause black smoke, and delays in responsiveness.

 

[Labsy]

If you've removed the DPF routines from the ECU, those sensors probably won't be monitored. You could pop the DPF out and check that it's clear, that would answer the "blockage" question.

Reaction time is affected by turbocharger spooling. This could be a worn turbo shaft, a leaking EGR valve or some opening in the exhaust (EGR tube cracked, gasket worn), a turbo actuator not pulling hard enough to open the vanes (usually vac hoses, but sometimes BCS). ALL of these will cause black smoke, and delays in responsiveness.

That's nice list of possible reasons. Now I need to figure out the way to diagnose, as in my case delay, smoke and bad response is random - sometimes it pullsy like it should, sometimes it just smokes. I can feel it....will try to record all possible data and make some conclustions out of those.
Thanx, Tony!

 

[Daan]

Hi Labsy....did you solve the problem? Im having the same problem with a customer Navara V9X....can you please update me on your findings and mail it to me. Regards Daan.

[email protected]

 

[Andy.ob]

Hi All,
Just wondering if Labsy managed to fault find and find the issue?
I keep getting a limp mode come up with similar issues and ive got a 600km drive home tomorrow…..going to be fun trying to not use much turbo and constant engine off/ons
Wish me luck