Sudden loss of power in Stx550

[apk47]

Hi,
I recently purchased a 2014 D40 Stx 550 with 119k on the clock. Did the 120k major service with nissan and had it thoroughly checked out before purchase. All seemed ok.
I did install an EVC throttle controller to remove some of the lag. (do not recall seeing this problem before this, however, I had not been on any longer trips before this was installed either, so not conclusive).

I have had an issue on longer trips, generally on the open road (around 100Kmh or higher) in 2wd mode and set in (auto).
Suddenly when I give it throttle, there is nothing there. The car can continue limping along 2-3K rpm but no power (40-60kmh).
I have tried stopping, turning throttle controller off, running in manual gears, even stopping and changing into 4wd high/lo and back.
The only way to seemingly rectify this condition, was to turn off the car wait a bit and turn back on. Then behaves normally.
However, in the last trip was forced to do this several times (6) and would only work for a few minutes before it did it again.
After the speeds dropped or rpm increased it came good again for the last 1 -2 hours of the trip.
I note this only happened on longer trips (not driving for a few minutes, usually 1hr + into a trip and then was fine for quite a long time afterwards. I have not seen this happen in slower speeds or while 4wding in high or 4lo regardless of how long I drove for, where the rpm seems to be higher.
I also note, that there is no error displayed when this occurred.

Does anyone have any theories about what the problem could be ?
Are there any tests I could do if this happens again to verify the theories?


Would appreciate any insights you may have.

Andrew.

 

[Old.Tony]

In the YD25 I'd suggest it's likely to be the SCV that's dirty or faulty. The very first thing to try is running a good injector cleaner through - something like Liqui Moly Fuel System Treatment. If you're really eager, Liqui Moly Diesel Purge (but be prepared to fiddle with the fuel hoses around your filter for this one). The diesel purge should take effect almost immediately. The other requires about 100km of driving for any difference to be noticeable. This has been successful in the past (on my own car, too).

There's a good chance this might work for your car too, so it's worth trying. If it DOES work, you might want to consider replacing the SCV, because debris can cause wear on it and it may not be long before experiencing the issue again. It usually triggers from high throttle input, which places more demand on the fuel delivery & return system.

It might be worth just disconnecting (not just turning off, but completely disconnecting) the throttle controller (this is free, and probably a good first step rather than paying $20 for injector cleaner). I'm not a big believe in these devices, usually all they do is modify the resistance from the actual throttle controller (which is just a variable resistor on a lever with a pedal attached for your foot) so you press your foot to achieve a certain level of power and the controller adds some to it increasing the signal to the ECU. As an electrical circuit, it can be affected by other things (and it's directly affecting the throttle inputs) so taking it out of the equation (completely) isn't a bad step.

 

[trimb]

Hi,
I recently purchased a 2014 D40 Stx 550 with 119k on the clock. Did the 120k major service with nissan and had it thoroughly checked out before purchase. All seemed ok.
I did install an EVC throttle controller to remove some of the lag. (do not recall seeing this problem before this, however, I had not been on any longer trips before this was installed either, so not conclusive).

I have had an issue on longer trips, generally on the open road (around 100Kmh or higher) in 2wd mode and set in (auto).
Suddenly when I give it throttle, there is nothing there. The car can continue limping along 2-3K rpm but no power (40-60kmh).
I have tried stopping, turning throttle controller off, running in manual gears, even stopping and changing into 4wd high/lo and back.
The only way to seemingly rectify this condition, was to turn off the car wait a bit and turn back on. Then behaves normally.
However, in the last trip was forced to do this several times (6) and would only work for a few minutes before it did it again.
After the speeds dropped or rpm increased it came good again for the last 1 -2 hours of the trip.
I note this only happened on longer trips (not driving for a few minutes, usually 1hr + into a trip and then was fine for quite a long time afterwards. I have not seen this happen in slower speeds or while 4wding in high or 4lo regardless of how long I drove for, where the rpm seems to be higher.
I also note, that there is no error displayed when this occurred.

Does anyone have any theories about what the problem could be ?
Are there any tests I could do if this happens again to verify the theories?


Would appreciate any insights you may have.

Andrew.

on the v9x assuming this happens after wide open throttle, its an overboost protection and yes turning off and on resolves it. Does on mine where this has happened under load accelerating hard up hill

 

[trimb]

on the v9x assuming this happens after wide open throttle, its an overboost protection and yes turning off and on resolves it. Does on mine where this has happened under load accelerating hard up hill

I would also check your EGR and make sure all your hoses and connections are good. Pressure leaks.wont help

 

[apk47]

In the YD25 I'd suggest it's likely to be the SCV that's dirty or faulty. The very first thing to try is running a good injector cleaner through - something like Liqui Moly Fuel System Treatment. If you're really eager, Liqui Moly Diesel Purge (but be prepared to fiddle with the fuel hoses around your filter for this one). The diesel purge should take effect almost immediately. The other requires about 100km of driving for any difference to be noticeable. This has been successful in the past (on my own car, too).

There's a good chance this might work for your car too, so it's worth trying. If it DOES work, you might want to consider replacing the SCV, because debris can cause wear on it and it may not be long before experiencing the issue again. It usually triggers from high throttle input, which places more demand on the fuel delivery & return system.

It might be worth just disconnecting (not just turning off, but completely disconnecting) the throttle controller (this is free, and probably a good first step rather than paying $20 for injector cleaner). I'm not a big believe in these devices, usually all they do is modify the resistance from the actual throttle controller (which is just a variable resistor on a lever with a pedal attached for your foot) so you press your foot to achieve a certain level of power and the controller adds some to it increasing the signal to the ECU. As an electrical circuit, it can be affected by other things (and it's directly affecting the throttle inputs) so taking it out of the equation (completely) isn't a bad step.

Old.Tony, thanks a lot, very helpful and seems likely this is the problem.
My plan is to get the fuel system treatment and replace SCV as you suggested and I will let you know how it goes.
I presume this is the part I need?

https://navlife.com.au/product/denso-dscv1031-suction-control-valve-d40-spain-v9x/
Thanks in advance

Is there anything else I can do to prevent this happening proactively in the future (pre filter for fuel for instance?)

Andrew.

 

[Old.Tony]

That looks like the part, but try @trimb 's suggestion too - overboosting will definitely do it as well. There's no sense replacing a good part to end up with the problem remaining.

As for prevention - that's hard to say. I had my genuine (original) replaced quite a long time ago and it had signs of wear (scoring) on it, but the replacement still sits in the car today. I suspect this replacement was not a "genuine Nissan" part, the mechanic didn't say but he was quite fond of using Chinese replacement parts. Not that I have a huge problem with that - I've bought from Chinese manufacturers before and have had very few problems (like wheel bearings, surprisingly, and a turbocharger).

The V9X did have two problems in the "charge air path" (the part of the intake between the turbocharger and the intake manifold). The hoses would balloon, and the top of the intercooler would expand. You might want to take a peek at your intercooler, but the hoses are harder to see unless you put a GoPro under the bonnet and drive it, or do a test on a dyno - because in neutral, the ECU won't let you boost up a lot.

 

[Pathfinder Benno]

Hi Andrew
See if this helps at all.
My ride is a TI Pathfinder with the 550 V9X engine.
I have had an issue with a loss of power, due no boost (I have a boost gauge) sounding similar to your report.
I also noted that when I lost power, cruise control would not engage, set speed showed flashing dash's.
The problem occurred intermittently over a long period of time with no warning lights.
The "fix" was usually ignition off & back on but the "fix" was masked by me playing with MAF sensors etc, so I was not convinced what was actually restoring power.
The final fix came about was when I again lost power, could not restore power & had a check engine light on for the first time.
I was away from home in Wagga NSW, got an auto electrician to put his scan tool on, it showed P0470, exhaust pressure sensor.
Auto elec suggested EGR clog might be the prob, took $110 from me & sent me on my way.
Could not get into a mechanical workshop so was left with Nissan!!!
Nissan diagnosed the same code but said there was also a wiring problem with the exhaust pressure sensor circuit, said there was a short at the sensor connector, pins were burnt & also the 5V supply wire was faulty somewhere between the sensor & ECU
They replaced the sensor, put a second hand sensor connector, (robbed from another Nissan engine because they said new connectors are not available, and a new harness was $1400 but not available in Oz.
Declared the vehicle serviceable & took $1100 from me & sent me on my way.
Original new connectors are available out of US of A, A$2.65 each, A$13 shipping, I now have 5 in hand.

There is more, but time to stop.

I can only suggest you get the ECU checked for any codes & if faults stored start from there.
I do have some extensive V9X manual info for t/shooting displayed codes, reply if I can be of assistance

Benno

 

[apk47]

Hi Andrew
See if this helps at all.
My ride is a TI Pathfinder with the 550 V9X engine.
I have had an issue with a loss of power, due no boost (I have a boost gauge) sounding similar to your report.
I also noted that when I lost power, cruise control would not engage, set speed showed flashing dash's.
The problem occurred intermittently over a long period of time with no warning lights.
The "fix" was usually ignition off & back on but the "fix" was masked by me playing with MAF sensors etc, so I was not convinced what was actually restoring power.
The final fix came about was when I again lost power, could not restore power & had a check engine light on for the first time.
I was away from home in Wagga NSW, got an auto electrician to put his scan tool on, it showed P0470, exhaust pressure sensor.
Auto elec suggested EGR clog might be the prob, took $110 from me & sent me on my way.
Could not get into a mechanical workshop so was left with Nissan!!!
Nissan diagnosed the same code but said there was also a wiring problem with the exhaust pressure sensor circuit, said there was a short at the sensor connector, pins were burnt & also the 5V supply wire was faulty somewhere between the sensor & ECU
They replaced the sensor, put a second hand sensor connector, (robbed from another Nissan engine because they said new connectors are not available, and a new harness was $1400 but not available in Oz.
Declared the vehicle serviceable & took $1100 from me & sent me on my way.
Original new connectors are available out of US of A, A$2.65 each, A$13 shipping, I now have 5 in hand.

There is more, but time to stop.

I can only suggest you get the ECU checked for any codes & if faults stored start from there.
I do have some extensive V9X manual info for t/shooting displayed codes, reply if I can be of assistance

Benno

Thanks Benno, sounds similar too. I have now ordered the Ultra gauge blue. This should be able to provide many of the stats from the ECU as well as diagnose/clear faults.
Is the V9x manual you have in digital format? If so, would it be possible to share?

Thanks in advance

Andrew.

 

[apk47]

I would also check your EGR and make sure all your hoses and connections are good. Pressure leaks.wont help

Trimb, could be, however, I am not sure that is consistent with the intermittent nature of this problem as I described? I would have thought that would not fix itself if this were the case later on in the drive?



Andrew.

 

[trimb]

Trimb, could be, however, I am not sure that is consistent with the intermittent nature of this problem as I described? I would have thought that would not fix itself if this were the case later on in the drive?



Andrew.

Guys I can only speak from my experience with my TI 550, and reading from other forums too.
What is consistent is that this happens under load. In my case when leaning on the throttle going up hill and in most cases without forcing a gear change...its a strange one.
I've never thrown a code (by way of seeing engine.check light) when thus has happened either. Just switched off and restarted. The full power is restored.
Let's keep sharing and learning

 

[apk47]

Guys I can only speak from my experience with my TI 550, and reading from other forums too.
What is consistent is that this happens under load. In my case when leaning on the throttle going up hill and in most cases without forcing a gear change...its a strange one.
I've never thrown a code (by way of seeing engine.check light) when thus has happened either. Just switched off and restarted. The full power is restored.
Let's keep sharing and learning

Trimb,
Yeah agree. Btw i see this happening slowly but steadily more often in mine. It used to reset after 1x then later to ok 2-3 and most recently did it 6 times. Each reset worked but would go back into limp mode after a free mins. Then eventually would rectify itself for the rest of the trip (next 1-2 hrs).
It started as really random occurrence.

 

[Old.Tony]

Trimb,
Yeah agree. Btw i see this happening slowly but steadily more often in mine. It used to reset after 1x then later to ok 2-3 and most recently did it 6 times. Each reset worked but would go back into limp mode after a free mins. Then eventually would rectify itself for the rest of the trip (next 1-2 hrs).
It started as really random occurrence.

Tried using any injector cleaner?

 

[apk47]

Tried using any injector cleaner?

Old.Tony,
Yes, purchased and filled tank yesterday, so still need time as I have only done 30ks up and down a strip of highway so far.
Will let you know if it improves. I have also booked it into a mechanic on Monday, and purchased the SCV.
Andrew

 

[Supermike]

Thanks Benno, sounds similar too. I have now ordered the Ultra gauge blue. This should be able to provide many of the stats from the ECU as well as diagnose/clear faults.
Is the V9x manual you have in digital format? If so, would it be possible to share?

Thanks in advance

Andrew.

I have the V9X manual as a digital copy of you need one.

Sounds like you are having similar issues to me. I can almost guarantee the EGR is the problem, forcing the truck into limp home mode, thus no turbo.

 

[apk47]

Old.Tony,
Yes, purchased and filled tank yesterday, so still need time as I have only done 30ks up and down a strip of highway so far.
Will let you know if it improves. I have also booked it into a mechanic on Monday, and purchased the SCV.
Andrew

Further update.
I have been doing the 20-30km drive daily and eventually, if I were over 100km's per hour it would start happening again and again. Finally got an engine light come up, with Mechanic booked in for Monday. Will get more of an idea what the issue is after they can read the fault. I did receive the spare SCV, so will see what the mechanic says.

I note that if I drive it in manual mode and keep RPM high, it doesn't happen.

Thanks for the help/advice.

 

[apk47]

I have an update. Took it to the mechanic and he couldn't replicate my issue, but it did throw up a fault. He disconnected the throttle controller.
I then found it didn't do it for a week but this morning got the error P2663. It seems similar to the following thread ( Ute in Limp mode fault code p2263 - SOLVED )

 

[Jamo]

Hi,
I recently purchased a 2014 D40 Stx 550 with 119k on the clock. Did the 120k major service with nissan and had it thoroughly checked out before purchase. All seemed ok.
I did install an EVC throttle controller to remove some of the lag. (do not recall seeing this problem before this, however, I had not been on any longer trips before this was installed either, so not conclusive).

I have had an issue on longer trips, generally on the open road (around 100Kmh or higher) in 2wd mode and set in (auto).
Suddenly when I give it throttle, there is nothing there. The car can continue limping along 2-3K rpm but no power (40-60kmh).
I have tried stopping, turning throttle controller off, running in manual gears, even stopping and changing into 4wd high/lo and back.
The only way to seemingly rectify this condition, was to turn off the car wait a bit and turn back on. Then behaves normally.
However, in the last trip was forced to do this several times (6) and would only work for a few minutes before it did it again.
After the speeds dropped or rpm increased it came good again for the last 1 -2 hours of the trip.
I note this only happened on longer trips (not driving for a few minutes, usually 1hr + into a trip and then was fine for quite a long time afterwards. I have not seen this happen in slower speeds or while 4wding in high or 4lo regardless of how long I drove for, where the rpm seems to be higher.
I also note, that there is no error displayed when this occurred.

Does anyone have any theories about what the problem could be ?
Are there any tests I could do if this happens again to verify the theories?


Would appreciate any insights you may have.

Andrew.

Hi Andrew,
I had similar issues, random loss of power, generally on open road and after trying to accelerate. I took it to a diesel upgrade shop and they identified the exhaust O2 sensor and the turbo controller. I changed both and all issues resolved, its an easy job to change both, buy the sensor socket, makes it a 5 min job. Bought a genuine Nissan turbo controller and after market O2 sensor. The issue was a faulty turbo controller and dirty sensor.
I get around 16 l /100km towing a 2.2T boat at 100 km/hr.
The exhaust/intercooler upgrade and retune are well worth the money.