sluggish 2.5 auto

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ericcs

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My car is starting to feel weird, and a little sluggish. firstly, i am getting much more induction noise through the snorkel when backing off. Cant see anything amiss, but the pipes either side of the the intercooler look to be trying to blow off, as they have moved around 5mm back.
also, i am using the torque app. and there is no boost/vacuum movement on the gauge!
Any clues anyone?
 

Old.Tony

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Hey Eric,


It sounds like no boost in terms of performance but overboost in terms of visible symptoms, which is why the hoses are trying to push their way off the intercooler on both sides. I assume that Torque has in the past shown the correct boost levels but now it doesn't? This does point to a sensor malfunction, but might be a faulty turbo.



We need to start with some basics.


1) Does the car start ok? If so, there's no blockage in the air path. At idle, a turbo that isn't turning is NOT a blockage, but an intercooler filled with oil is.


2) Is there any smoke apparent if you're following the car? Tons of black smoke means your turbo is probably not working much at all (which also means the boost sensor is probably ok) OR the EGR valve is letting too much exhaust in. If there's no black smoke at all when the car is floored, it's likely that the turbo is overboosting - although they usually perform well, they don't go sluggish (unless there's a second problem).


3) If the power problem appears only after using full accelerator (in other words, the car drives normally up to the time that you use a lot of throttle) it's probably the SCV. You may notice the engine "hunting" at idle, where it gets little surges but doesn't settle to a nice steady drone. Injector cleaner might help it for a little while but ultimately this is a sign that the SCV needs replacing.



I'm assuming the air filter's been checked and you've cleaned the MAFS.


If there's heaps of black smoke, it could be turbo or EGR (most common, assuming the airway is clear). Turbocharger is usually vacuum lines, or the boost control solenoid. You can test the solenoid - take the vac hose that runs across the top of the motor off and connect it directly to the turbocharger. Be gentle if you take it for a drive, you'll overboost really easily and the ECU won't be able to back the boost off as you decelerate, so have some tools with you in case one of the charge air hoses pops off. When you do connect that hose to the actuator, you should immediately see the arm underneath it move (take it on and off a couple of times).


If the actuator arm doesn't move, either that vac hose is toast (possible), the vac pump has failed (unheard of) or the actuator has a busted diaphragm (very rare). It's usually just the hose. If connecting the hose directly makes it suddenly work better, the Boost Control Solenoid is shot. I got tired of replacing mine and went with a Tilix valve.
 

KevinE

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Please post a photo of the front of your car. Have you recently put spotties, or a light bar/bullbar/etc onto the car? Maybe a car bra?

It sounds like the air flow over the intercooler has been restricted?
 

ericcs

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Please post a photo of the front of your car. Have you recently put spotties, or a light bar/bullbar/etc onto the car? Maybe a car bra?

It sounds like the air flow over the intercooler has been restricted?
Kevin, nothing has changed on the car for many years now, and hoses that are trying to blow off are on each side of the intercooler. the really loud induction noise through the snorkel has me stumped!
 

ericcs

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Hey Eric,


It sounds like no boost in terms of performance but overboost in terms of visible symptoms, which is why the hoses are trying to push their way off the intercooler on both sides. I assume that Torque has in the past shown the correct boost levels but now it doesn't? This does point to a sensor malfunction, but might be a faulty turbo.
yes Tony, i always could read vacuum and boost, now absolutely no movement



We need to start with some basics.


1) Does the car start ok? If so, there's no blockage in the air path. At idle, a turbo that isn't turning is NOT a blockage, but an intercooler filled with oil is.
Car starts and idles normally, pipes either side of the intercooler are trying to push off


2) Is there any smoke apparent if you're following the car? Tons of black smoke means your turbo is probably not working much at all (which also means the boost sensor is probably ok) OR the EGR valve is letting too much exhaust in. If there's no black smoke at all when the car is floored, it's likely that the turbo is overboosting - although they usually perform well, they don't go sluggish (unless there's a second problem).
no excessive smoke, i have changed the vac hoses and boost control valve recently, EGR has been blocked for many years



3) If the power problem appears only after using full accelerator (in other words, the car drives normally up to the time that you use a lot of throttle) it's probably the SCV. You may notice the engine "hunting" at idle, where it gets little surges but doesn't settle to a nice steady drone. Injector cleaner might help it for a little while but ultimately this is a sign that the SCV needs replacing.
feels sluggish all the time



I'm assuming the air filter's been checked and you've cleaned the MAFS.
filter is clean, but haven't cleaned the MAFS


If there's heaps of black smoke, it could be turbo or EGR (most common, assuming the airway is clear). Turbocharger is usually vacuum lines, or the boost control solenoid. You can test the solenoid - take the vac hose that runs across the top of the motor off and connect it directly to the turbocharger. Be gentle if you take it for a drive, you'll overboost really easily and the ECU won't be able to back the boost off as you decelerate, so have some tools with you in case one of the charge air hoses pops off. When you do connect that hose to the actuator, you should immediately see the arm underneath it move (take it on and off a couple of times).
when i start the car, i can see the turbo actuator arm pull up


If the actuator arm doesn't move, either that vac hose is toast (possible), the vac pump has failed (unheard of) or the actuator has a busted diaphragm (very rare). It's usually just the hose. If connecting the hose directly makes it suddenly work better, the Boost Control Solenoid is shot. I got tired of replacing mine and went with a Tilix valve.
i remember when you fitted the tillix valve, but i had already bought a new BCS


I had the transmission oil done last week, and even though it felt sluggish after, i can't think that would had any to do with it!
As i mentioned, it sounds much louder through the snorkel when the throttle backs off!





 

Old.Tony

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Wow, Eric, it looks like overboost due to the pressure sensor not working at all.


On the inside of the engine bay near the battery there should be a small sensor with a hose that runs out to the intercooler. This is the turbocharger boost pressure sensor. Check its electrical connections. I've never heard of one failing, but electrical connections can and have failed sometimes for no reason, other times it's pressure washing the engine bay.


It seems everything else is behaving itself. The other end of the wires connecting to the sensor go in through the IPDM/ER and then to the ECU. A quick rattle around in those connectors might prove fruitful if cleaning the sensor doesn't give you a win.
 

ericcs

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Wow, Eric, it looks like overboost due to the pressure sensor not working at all.


On the inside of the engine bay near the battery there should be a small sensor with a hose that runs out to the intercooler. This is the turbocharger boost pressure sensor. Check its electrical connections. I've never heard of one failing, but electrical connections can and have failed sometimes for no reason, other times it's pressure washing the engine bay.


It seems everything else is behaving itself. The other end of the wires connecting to the sensor go in through the IPDM/ER and then to the ECU. A quick rattle around in those connectors might prove fruitful if cleaning the sensor doesn't give you a win.
is this the same hose you break into to hook up a boost gauge, as I might have to fit one if I can't get the torque app to play. I had a quick look for the sensor today, but couldn't see it . will take off the grill for a better look!

ps, how do I shrink the picture size?
 

Old.Tony

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You could fit a boost gauge in that hose, yes. It's certainly a good place to do it, it's on the cool side of the intercooler, it should have less oil mist and it's close to solid structures so you can easily route cables/tubes away from the engine/radiator fan etc. Torque gets its data from the ECU, the ECU gets boost pressure from that sensor, and if it's not getting the right info from the sensor it's not going to do the right stuff with your turbo. I'm thinking, though, that overboosting doesn't usually make the engine sluggish, although there's no telling what the fuel commands are with the ECU having issues getting some sensor readings. How's your fuel rail pressure look - does that appear normal while driving?

When you're preparing images, most image processing tools have an option to resize the images. In MSPaint, under the 'Home' menu, click 'Resize', make sure 'Maintain aspect ratio' is ticked then use either method to reduce the size - images that are about 800 pixels horizontally work well for me. You can also use this tool to crop away everything but the image part you want.


For instance, the last image you have there, I downloaded it and used MSPaint to resize it to 800pixels horizontally and got this:




I then used the 'Select' tool to choose an area of interest from that photo and then clicked on 'Crop' to keep just that area and discard the rest, to get this result:


 

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bods

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Over boosting could cause sluggishness Tony. Especially if the turbo has the vanes fully open (or closed whatever way they are to create full boost) as the ecu could be trying to get a boost reading, so is running the turbo at full boost until it can make adjustments. If that's the case, it will take a little while to start spooling as it takes more energy to get it moving. I'm under the impression that's why they came up with the idea of variable vane/nozzle turbochargers. So at high engine load and low rpm they adjust the vanes to make boost more linear than a standard turbo would under the same conditions.

If the vanes are set to produce full boost, that could also explain the weird induction noise under closed throttle as the turbo would still be pulling plenty of air in...

Of course all of what I've said could be a load of crap that makes no sense and it is some other problem... Haha :) good luck.
 

ericcs

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cheers Bods, when i get a chance i'll check the boost sensor to see why i'm getting no reading at all. my interpretation is when the car off, the vanes are open, then close off when it starts. mine is doing that, but after that, who know's!
 

bods

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Fair enough. That's all I can think of, that the ecu is adjusting the vanes to try and get a boost reading, but because the boost sensor isn't sending back a reading it holds it there... I'm surprised it hasn't gone into limp mode as it isn't getting a boost signal, but maybe it hasn't failed completely...
 

ericcs

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back to normal, all it was, was the boost sensor hose somehow came adrift. thanks Tony!


 
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Old.Tony

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beats me how it came off, as you can't get your hand in there to put it back on without unbolting the intercooler!

A bit of overboost? If the turbo is peaking and you hurriedly take your foot off the throttle, the vanes will close on the turbo but it will still - for a brief period - be producing a lot of pressure. I've had the charge air hose pop off the back of the intake manifold before. Bloody thing got me in the twisty sections of the Putty Rd towing the caravan too. Talk about black smoke!
 

ericcs

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you might be right with the over boost, occasionally it will hit 22psi. don't know if that's too much?
might zip tie it when i get around to cleaning the intercooler!
 

Old.Tony

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22psi isn't too high, before I'd adjusted my Tilix valve properly it was hitting 24, but that's also when the intake hose kept popping off too.


Perhaps I should check my own boost sensor hose. It could be holding on by the smallest amount - she's done a few miles now and I'm sure the rubber isn't in as good a condition as it used to be!
 

ericcs

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22psi isn't too high, before I'd adjusted my Tilix valve properly it was hitting 24, but that's also when the intake hose kept popping off too.


Perhaps I should check my own boost sensor hose. It could be holding on by the smallest amount - she's done a few miles now and I'm sure the rubber isn't in as good a condition as it used to be!
Tony, does it change the power delivery in any way, like, is it more linear?
 
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