Turbo Whirl?

[mickstanz]

Just when i think i'v got my Nav running good this happens..

I'v noticed a whirl noise coming from the turbo when i let off the accelerator and a constant whirling/whine when cruising - mainly when boosting, if i let off then it goes away. Will do it when stationary as well.

Have checked all vacuum hose's, and all my hoses to oil catch can, changed my EGT blank back to factory etc.. have had the mrs rev it up while i'm under the hood and it definitely sounds like its coming from the turbo..

Sounds pretty much exactly like the last 2 seconds of this video..

https://www.youtube.com/watch?v=Oxm1Xf6DBz8

Heres a sound clip that i took while next to the turbo.. reving up, can hear the turbo with the Plazamaman pipe and then the noise that i'm referring to..

http://vocaroo.com/i/s06q12VhB85z

Any advice would be appreciated guys, heres hoping the turbo isn't shot..

 

[Old.Tony]

Check around the exhaust manifold -> turbocharger connection. Look for signs of soot. Mine came loose and made a similar sound. Chances are the gasket will need to be replaced.

 

[mickstanz]

Cheers Tony hopefully thats the case. I had a look yesterday but couldnt see much of the turbo etc i guess i need to remove all the heat sheilds etc?

 

[mickstanz]

Also not sure if this is a new thing since this noise started but my boost is spiking.. this graph is of 5th/6th gear.. spikes up to around 20/21psi, or is this normal?

 

[NAV012]

Pretty sure champ the D40s boost up to about 28psi

Others in the know feel free to answer into this further

 

[mickstanz]

http://www.navara.asia/showthread.php?t=32470

I think around 23 or so is max, so i think im within limits but the curve of the graph seems strange to me.. dont know if has to do with the sound or not

 

[mickstanz]

Just to add more confusion to the mix... taking off from a stand still it gets to 5th gear no trouble, then the turbo seems to stop at 2500rpm, then kicks in a few seconds later, then 6th does the same, and then my air conditioning fan goes to about half power and my speedo jumps down about 15km/h then bounces back up to speed...

Gave it a 0-130ish km/h test after that and all was fine, just a hell of a whistle coming from engine at about 130km/h..

Over the weekend ill get a chance to have a look for any problems with the gaskets around turbo/exhaust etc but as far as the fan and speedo goes that sounds electrical?

 

[Old.Tony]

Task 1 - vital to do - get a jumper pack or some 12V source and connect it to both battery terminals. Remove both terminals from the battery and clean them. I had a similar instrumentation malfunction and it was my negative battery terminal.

An erratic electrical connection can cause all sorts of problems sending you in all sorts of directions dealing with symptoms of problems that don't exist. Your turbocharger variations could be due to a damaged vacuum hose, or a faulty vac solenoid. Since the vacuum is controlled electrically, it could also be interferred with by a poor electrical connection.

The turbocharger-to-manifold interface should be visible by leaning over the left-hand headlight - works for me, but I'm fairly tall which does help! You can also see the bottom from underneath if you don't have bash plates. Otherwise, an inspection camera or mirror can help.

D40 turbocharger is capable of a peak of around 24psi, you might squeeze a fraction more out of it momentarily while the vanes are open, the turbo is fully spooled and the throttle is released but typically you'll see peaks around 19-20psi. The engine will cope with 30+ (Bluenavara has run his at 36psi) but I'm not sure what modifications are required to the intake manifold/EGR valve/intercooler/charge air hosing in order to hold that sort of pressure for long.

 

[mickstanz]

Once i hook the battery jumper up Tony then what do i do? Try and drive it using the jumper? Or is it just there to keep charge while i clean terminals?

Im short but jumped up there just now and looked everywhere, took the heat sheild off the turbo area and looked there as well and cant see anything...

 

[Stelianos]

Task 1 - vital to do - get a jumper pack or some 12V source and connect it to both battery terminals. Remove both terminals from the battery and clean them. I had a similar instrumentation malfunction and it was my negative battery terminal.

An erratic electrical connection can cause all sorts of problems sending you in all sorts of directions dealing with symptoms of problems that don't exist. Your turbocharger variations could be due to a damaged vacuum hose, or a faulty vac solenoid. Since the vacuum is controlled electrically, it could also be interferred with by a poor electrical connection.

The turbocharger-to-manifold interface should be visible by leaning over the left-hand headlight - works for me, but I'm fairly tall which does help! You can also see the bottom from underneath if you don't have bash plates. Otherwise, an inspection camera or mirror can help.

D40 turbocharger is capable of a peak of around 24psi, you might squeeze a fraction more out of it momentarily while the vanes are open, the turbo is fully spooled and the throttle is released but typically you'll see peaks around 19-20psi. The engine will cope with 30+ (Bluenavara has run his at 36psi) but I'm not sure what modifications are required to the intake manifold/EGR valve/intercooler/charge air hosing in order to hold that sort of pressure for long.

actually it cant cope with 36psi since Bluenavara's engine blew up after 5-6 months as he said he mentioned in the europe forum somewhere. he was also sick thats why he stopped updating sadly

 

[bods]

Once i hook the battery jumper up Tony then what do i do? Try and drive it using the jumper? Or is it just there to keep charge while i clean terminals?

Im short but jumped up there just now and looked everywhere, took the heat sheild off the turbo area and looked there as well and cant see anything...

Yeah mate, the jumper is to keep power to the vehicle while you are cleaning the terminals. Probably wouldn't hurt to give the earth point near the ecu a good clean too.

 

[Old.Tony]

Yes, the jumper pack maintains ECU power so you don't lose trip meter/radio PIN/window settings.

Inspecting the EGR tube would be my next thing. A leaking EGR tube directly robs the turbocharger of exhaust pressure and would make some noise, from a squeal (fine crack) to a whirring (large crack allowing the puffs of each exhaust stroke to escape). This could occur anywhere along the tube, it's more commonly right near the exhaust manifold connection as it cracks around the weld, but it could crack anywhere really.

A large leak in the EGR would result in boost loss but it should be fairly obvious. I don't think your EGR valve is stuck, because you replaced the gasket and didn't notice a hole in the EGR blanking plate.

 

[mickstanz]

Cheers guys, have done as much as i can do i think and its still there. I'll look into the electrical side myself, but im gonna take it to the dealer to get the noise fixed next week, its gonna be something simple i think and theyre gonna charge through the roof but i havent got the time (and the skills needed!) at the moment to fix it myself.

In January im giving it a full service, air intake manifold, intercooler etc all cleaned out and ill be installing my duel battery and fixing up all the spot light wiring etc when i do it as its all just a bit messy right now, so hopefully that should sort out the electrical side if i havent fixed it before then!

Cheers again guys ill update once its been fixed at the shop incase anyones in the same boat in the future.

 

[mickstanz]

Update: turbos on its way out..

 

[kernels]

Did you catch it early enough to get away with a rebuild kit ?

 

[Old.Tony]

Kits are available on eBay like this one.

 

[mickstanz]

Are the kits DIY or professional?

Not 100% sure if i caught it in time tho, how do ya tell?.. im gonna drop a Forefront one in there i think, hope to do it myself

 

[bods]

A direct changeover will be easy to do yourself. Replacing the core or bearings, well that depends how mechanically minded you are.

 

[mickstanz]

Alright.. im a farmer so usually manage to get most things working but dont know if i would trust myself with something like a rebuild kit.. might just be a direct replacement.. Forefront seem to have positive reviews from what iv read unless theres something else i should look at? Nissan quoted 1600 for a turbo they couldnt tell me the brand of and like 3000 for genuine Nissan. 6 hours labour, basically 800 though seems a bit steep, think ill have a crack at it

 

[bods]

yeah right... my only advice would be to soak the dump pipe studs/bolts and manifold studs in crc or penetrene (or some sort of lube) for a day or 2 before trying to remove the old one. it will make it a lot easier to get it undone... apart from that, there's not a lot to it.