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Lack of power when overtaking

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eugeneb

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Hi

Not quiet a Navara, but it could be a common issue! I have an 2007 R51 Pathfinder with a 2.5YD engine and Autobox. Its done a little over 200,000km. Over the past few months I have been dealing with various niggling power related issues. I have no ECU codes. A few weeks ago after cleaning the MAF, replacing the boost solenoid/vacuum lines, air cleaner, fuel filter and performing a fuel pump reset, I thought I'd sorted it, I seemed to have a lot more power. However I am now finding that when I try to overtake on the open road (100km/h) it sometimes doesn't seem to have any power and I struggle to get over 110km/h. The auto box initially changes down and then at about 4500 RPM changes back up at which time I have no power.. It doesn't go into limp mode. Other times it pulls like a train. Has anyone had this experience it doesn't fill you with confidence....
 

Old.Tony

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I don't normally let mine rev much over 3500rpm, peak horsepower is around there and peak torque is at 2000rpm.

At those high revs, the important thing is flow. The intercooler needs to be fairly clean (I rinse mine with petrol, 5 or 6 times, then reinstall). The turbocharger needs to spin freely and not have any problems with its (journal) bearings. The Garrett 2056V isn't a bad turbocharger, but it can suffer from prolonged high demands as the impeller is drawn forward in the housing, placing strain on the (brass) bearings and loosening the fit, eventually allowing the impeller to make contact with the housing which slows it down reducing boost and adding a bunch of metal filings to the intake!

I would suggest two things to start with:

1) Remove the front grille, then the intercooler. Place one hand over one of the openings of the intercooler and keep the other opening uppermost, then pour petrol in it (about 50-100ml is enough). Put your hand over the uppermost opening and turn the intercooler over, releasing the hand that is now on the top momentarily to release the pressure, then turn it back the way you started - repeat this little dance a couple of times to swish the fuel back and forth through the cores. Pour it out into a container, it should be black. Repeat the whole exercise until you can start seeing "petrol" colour coming out.

2) Remove one end of the hose connecting the intercooler to the baffle and wipe a finger on the inside. Now, under a very bright light, inspect your finger. If you see any sign of metallic reflections, your turbocharger has been grinding away at itself and needs replacing. There's a company in Qld that sells genuine Honeywell Garrett 2056Vs for a very reasonable price (there's one under my bonnet right now, very happy with it). I'll get the company info for you if you need it.
 

eugeneb

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Yeah I normally only goto about 3K, but you know what its like when you need to overtake! Floor it and off you go.... Couple of things turbo related, there seems to be quite a bit of oil in the cooler pipe from the turbo, which I think is normal? Also usually on startup from cold the turbo does make quite a high pitched whine when pulling off from a stand still at lower rpms, once warmed up a bit you don't seem to get the whine. Does this sound like a turbo issue?
 

Old.Tony

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A bit of oil in there is fine, because the PCV outlet is connected to the air pipe on the intake side of the turbocharger - all the gas and vapour passing out of the PCV will also go through the turbocharger. That's normal operation, if you don't like the oil there (and in your intercooler!) you could fit a catch can to reduce the amount.

A whine when cold might mean the bearings aren't 100%, it's probably time to pop the hose off the front of the turbo and check the sideways movement of the impeller (when cold).
 

eugeneb

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A bit of oil in there is fine, because the PCV outlet is connected to the air pipe on the intake side of the turbocharger - all the gas and vapour passing out of the PCV will also go through the turbocharger. That's normal operation, if you don't like the oil there (and in your intercooler!) you could fit a catch can to reduce the amount.

A whine when cold might mean the bearings aren't 100%, it's probably time to pop the hose off the front of the turbo and check the sideways movement of the impeller (when cold).
Hi

It looks like I may need a turbo, just looking over here and I can get exchange units for about $1500.00, how does that compare with your supplier?
 

eugeneb

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I need to confirm that the exchange unit is a recon Garrett and when they will have stock. I assume was yours an recon exchange unit as well? If it was an exchange there's probably nothing in the prices!
 

ericcs

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A bit of oil in there is fine, because the PCV outlet is connected to the air pipe on the intake side of the turbocharger - all the gas and vapour passing out of the PCV will also go through the turbocharger. That's normal operation, if you don't like the oil there (and in your intercooler!) you could fit a catch can to reduce the amount.

A whine when cold might mean the bearings aren't 100%, it's probably time to pop the hose off the front of the turbo and check the sideways movement of the impeller (when cold).
if it is the turbo, and you started it up with the hose of the front of the turbo, that whine would be louder?
 

Old.Tony

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if it is the turbo, and you started it up with the hose of the front of the turbo, that whine would be louder?
You'd imagine so! It's not uncommon for the air path to be rebuilt to allow the turbo noise out. You still need the MAFS intact, so I guess the best you could do is a short piece of pipe off the turbo to a section containing the MAFS, then a short piece of pipe to a filter like a K&N pod filter. It won't be the best, cleanest air going into the engine (and this might extract a price later on) but you'd hear that turbo whistling Dixie!

I need to confirm that the exchange unit is a recon Garrett and when they will have stock. I assume was yours an recon exchange unit as well? If it was an exchange there's probably nothing in the prices!
Mine was a brand new unit, no exchange, no reconditioning. Got it from a company up in Queensland. Still have the box, it's out in the shed and I can't get to it at the moment, but I could go through my bank statements and find out who we paid for it.
 

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