Navara D40 2009 - No power at higher speeds

[kwilko]

No power especially in 5th/6th gear.

I have a 2009 Navara D40, 4x4 4dr, 2.5 diesel turbo.

The other day I gunned it up a hill and the realised I had a loss of power. On the flat at about 100 kph if I put the throttle on, all I got was black smoke.
on returning to lower speeds in 3rd and 4th gear the vehicle appeared to be pulling fine again.
I am mostly driving in 3rd and 4th gear at present as I'm living on an island with very few open roads.....so the opportunity to drive over 80 kph is quite rare at present.

Any advice on what the problem might be?

 

[bods]

Hey mate, I'd be having a look at the neutral position switch. These are a common problem to fail causing loss of power especially in higher gears.

 

[kwilko]

Can you explain a bit more?
I have had work done on the gearbox

 

[bods]

Not really as I haven't got a d40, but if you have a look through the d40 section there has been threads mentioning it. Maybe even try a search for NPS or neutral switch and you should have some luck.

 

[bods]

Not really the same issue as yours, but may help locating the switch. http://www.navara.asia/showthread.php?t=30822

 

[kwilko]

my vehicle is a 6 speed manual

 

[bods]

Apparently the original poster in that thread does too. According to it, there are 2 switches on the side of the gearbox and the upper one is the neutral position switch.

Apparently on the right side of the gearbox.

 

[Old.Tony]

The other possibility is the turbocharger. There could be a couple of things wrong.


* BCS not working properly. These are prone to failure. I've had three fail, I'm now using a Tilix valve (it's like a Dawes valve). Watch the arm under the actuator on the turbocharger while the car is being revved in neutral by a helper. The arm should move. If it doesn't you may have a failed BCS, a failed actuator, or a vacuum leak.


* Replace the vac hoses - you'll need 3metres of 3mm inner diameter fuel-safe rubber hose. While you're replacing the one that goes to the turbocharger, connect it first to the actuator then suck on the other end. The actuator arm should move. If it doesn't, the actuator has failed or is jammed. If the actuator responds, try the car again, if it still doesn't work properly, the BCS may have failed.



* Failing turbocharger. If you've got something giving you boost pressure figures, watch them, your boost should peak up around 20psi. When my BCS failed, my boost pressure peaked around 6psi. If you're not even seeing that, pull the hose off the front of the turbocharger and spin the impeller. It should not wobble/wiggle, it should move smoothly without feeling rough. It should resist a little, and stop fairly quickly if you can spin it. If there's a wobble in the shaft, the turbocharger may be stalling instead of spooling properly. If you are replacing the turbocharger, make sure you get a replacement gasket kit with the turbocharger.



* Check and clean the MAFS. Don't put anything in the hole in the end, use an electrical contact spray. This is in the back of the air pipe just out from the air filter.


There are other possibilities. Dirty/damaged SCV on the fuel pump. Dirty air filter. Leaking manifold causing boost pressure to be lost (look for signs of black oil smeared around the leak).


Have a look at those and get back to us.

 

[kwilko]

Thanks - this is going to take a while - the next time I can get a guy to check it is next Tuesday.....

BTW - what does BCS stand for and what does MAFS stand for?

 

[Old.Tony]

BSC is the Boost Control Solenoid. It's a small black device sitting on the back of the solid pipe that connects to the intercooler at the front of the car. It will have a couple of wires and 3 vacuum lines attached to it, one of these will go straight up to the turbocharger actuator. If you can't fine it, go to the turbocharger and follow the vac line back to it. The BCS is not repairable.


MAFS is the Mass Air Flow Sensor. It's about the size of a credit card, it measures temperature and flow rate of the incoming air so the ECU can adjust the fuel flow properly, among other things (like turbocharger control, because that's directly air-flow related).

 

[ericcs]

as per Tony's suggestions.
read this link, this was my car!

http://www.navara.asia/showthread.php?t=35145

 

[KevinE]

Hey Tony, are 5th & 6th in a manual D40 both overdrive gears? It's just that in the OP kwilko says that the car still pulls in 3rd & 4th. Wouldn't that rule out turbo & MAFS issues?

It sounds like something is draining power from the engine, but the lower gear ratios are able to pull with what's available in the way of HP/KW.

kwilko, thinking along the lines of normal fault finding & checking the simple stuff 1st, I'd be looking at a blocked air filter, or blocked inlet manifold & if they're all good, I'd move onto the fuel filter & fuel system, then if still not resolved, I'd check for computer software & hardware issues. A simple reset of the ECU may be all it needs. But it does sound like an air, &/or fuel blockage to me.

There's also the fuel pump down by the oil filter on a 2.5 in a D22. I'm not sure if a D40 has that? If so, they are prone to failure.

Good luck with it!

 

[kwilko]

I noticed this morning that after about 5 or 10 starting the engine was running apparently fine. I pulled well in 5 th up to 100kph plus, before running out of road; I suspect I get this trouble once the whole system is fully warmed up......

 

[Old.Tony]

It's a different fuel pump on the D40, it's not a VP44 and the D40 pump seems to be quite reliable. The SCV isn't, but that's a replaceable part on the pump and not the pump itself.


Please remember bod's advice too - there's a good chance it's to do with the neutral position switch. 5th is not overdrive, but it's aligned on the same side as 6th, so the gear lever has been pushed over to the right for both. The switch needs to be unplugged to figure that out.

 

[kwilko]

Well it seems to have been the SCV - Suction Control Valve.

I gave them a list of possibilities and they replaced this, a diesel filter and some air filters - they also kept the car a day to remove buildup of carbon deposits from the exhaust system.
total cost was about 3500 baht = $AU100.

Because they had the car for an extra day I kept my rental motorbike for and extra day, but the throttle stuck whilst parked in a traffic jam and I crashed into a minibus.......this did 13000 baht of damage to the bus and the bike has yet to be estimated...........

 

[bods]

Oh man... hopefully your problem with the d40 is fixed anyway...

 

[fitzie]

If the nps is faulty will it throw a fault code

 

[kwilko]

Oh man... hopefully your problem with the d40 is fixed anyway...

It's going like a rocket now......I think there has been a build-up of lack of performance for about a year and Nissan Samui put it on their computer and tweaked a few things and cleaned out the exhaust etc with a lot of beneficial results. I've replaced the shocks at the front and serviced the bushes too, it's like a different truck. I till need to address the rear suspension - it has an extra leaf and squeaked a lot....

so touch wood, all I ha to do next month is pay for the damage to the Minivan and the motorcycle........

 

[kwilko]

BTW - my malware program always picks up a trojan threat from this site....

 

[KevinE]

BTW - my malware program always picks up a trojan threat from this site....

Mine too.