d40 2012 ST power loss towing

[Bassplumb]

Hi guys, i got my D40 2012 ST Spain build ECU remapped/tuned + EGR block off and I'm now having problems with sudden power loss. Seems to ONLY happen when towing in 4th/5th gear @ 2000rpm on a Incline,
No engine lights come up and if i let my foot off the accelerator and go again its fine power kicks back in.
Anyone had this issue? The tuners have had a look and replaced the fuel filter but yet still couldn't seem to find anything wrong..

 

[Old.Tony]

It's not something I've ever experienced and I've been in that situation many times except for the tuning changes. I wonder if something in that is going out of range causing the mapping to reduce fuel input, or lower boost? It would be interesting to see a graph of the following things together:

1) Throttle position
2) Engine load
3) Fuel rail pressure
4) Boost pressure

SCV faults are usually fixed by the turn off - turn on method, backing off the throttle has not fixed it in the past so I doubt it's an SCV issue (or a fuel pump/injector issue).

Has your car had its turbo actuator replaced by Nissan? There were a batch of fauloty electronic turbo actuators that had to go back to Nissan for replacement. If this was causing your problem you'd probably notice a fair amount of black smoke just as the power declines (same fuel, less air). If the smoke from your exhaust is normal/missing then I'd say it's a fuel input issue which is governed by the tune.

 

[Bassplumb]

Cheers Tony. I am not sure if the actuator has been replaced as i am the second owner. I do know that before the tune i towed alot with no issues.
Is it was to be the actuator would it not happen when vehicle isnt under load?

 

[vicszd30]

Howdy BassPlumb - I have been having issues with mine also doing the same thing, mines a zd d22. Sorry to "but in" but I might be able to get another view /opinion and solve this "bug" I have with my zd "with the help of your diagnosis" ..
Interesting Tony- regarding the s.c.v and the engine warning light ignition on off x3 routine... I thought mine was doing it because of the Glow Plug issue but it did it again last week. Would the s.c.v issue/problem cause the zd30 to use more fuel?
And regarding the "flat spot" in 4th and 5th I did replace the n.p.s on the gear bag put it still has this "flat spot" every now and again! Sometimes B/Plumb the n.p.s goes and causes this issue!
Tony- is there a way of cleaning/inspecting this valve? cheers vic

 

[bods]

Howdy BassPlumb - I have been having issues with mine also doing the same thing, mines a zd d22. Sorry to "but in" but I might be able to get another view /opinion and solve this "bug" I have with my zd "with the help of your diagnosis" ..
Interesting Tony- regarding the s.c.v and the engine warning light ignition on off x3 routine... I thought mine was doing it because of the Glow Plug issue but it did it again last week. Would the s.c.v issue/problem cause the zd30 to use more fuel?
And regarding the "flat spot" in 4th and 5th I did replace the n.p.s on the gear bag put it still has this "flat spot" every now and again! Sometimes B/Plumb the n.p.s goes and causes this issue!
Tony- is there a way of cleaning/inspecting this valve? cheers vic

Sorry vic, you're outta luck there. The zd30, being direct injection, doesn't have a suction control valve. That is for the common rail motors only. I do believe you should have a little gauze filter inside the banjo fitting on the back of your injector pump though, which may be worth a look...

 

[Old.Tony]

The SCV can be cleaned, and because it's an inexpensive and often fruitful action it's what I always recommend to be done first. Thoroughly clean with unleaded petrol (doesn't matter what grade, and you could use xylene or any other industrial solvent). Rinse it well with diesel (leave it 'wet', too) before reinstallation.

A boost gauge of sorts will help diagnose the actuator. Grab a $5 OBD-II ELM327 bluetooth adapter from eBay and in the Android Play store, search for "Torque" by Ian Hawkins. Absolutely brilliant piece of software. Add a gauge, get it to show boost pressure (either "Intake Manifold Pressure" or further down the "Turbo Boost & Vacuum Gauge"). Now just watch it as you drive. It should vary depending (mostly) on how hard you're pressing the pedal.

If it's not, your actuator might have a problem.

It would also be interesting (with that program running) to watch the fuel rail pressure. If it's spiking, I'd wonder if there's a dirty electrical contact in the turbo boost pressure sensor (low on the vehicle's right side of the intercooler) or the MAFS (in the air intake just out of the air filter box). Actually pull that MAFS out and clean it regardless. Be careful, $400 in your hands ... please ONLY put the electrical contact spray or MAFS spray into that little hole. Do NOT be tempted to put in anything else.

 

[vicszd30]

Sorry vic, you're outta luck there. The zd30, being direct injection, doesn't have a suction control valve. That is for the common rail motors only. I do believe you should have a little gauze filter inside the banjo fitting on the back of your injector pump though, which may be worth a look...

Ahhhh thanks for that Bod's lol I'll cling to anything if there is a hope of getting better fuel economy
And with that Bango bolt-That's good info, I will have to grab some new copper washers and take a look at that for sure! cheers fella-Vic..

 

[ridges]

While towing a dodgy trailer I had power loss if I towed with the headlights on. There was an electrical short on the trailer causing some havoc with the ST's computer. Headlights off and she pulls fine, soon as I flick the lights on the power dropped to about a quarter and it struggled to tow. Not sure if it'll be related to you but might be worth having a look.

 

[bods]

While towing a dodgy trailer I had power loss if I towed with the headlights on. There was an electrical short on the trailer causing some havoc with the ST's computer. Headlights off and she pulls fine, soon as I flick the lights on the power dropped to about a quarter and it struggled to tow. Not sure if it'll be related to you but might be worth having a look.

That would have been the trailer's tail lights shorting out with the brake lights, making the brake lights on your ute come on all the time. Apparently in d40s the computer senses when the brake lights are on and limits power...

 

[Bassplumb]

cheers, all these possibilities are a tad out of my ball park..
does anyone know or recommend Diesel tech/tuner/diagnosis around Eastern suburbs of Melbourne whop i can trust to resolve the problem?

 

[bods]

It wouldn't hurt to check on the neutral position switch. Normally the test is to hold the gear stick to one side, either left or right, when the surging happens... won't cost anything to try that...