Wont' boost EGTs up out of ideas?

Sorry I've reposted this as I'm out of ideas and need some help if possible.

So something's not quite right.

I'm just going to dump all my observations here, it may mean something to someone with more experience.

About 2 weeks back more than usual oil began coming through the catch can, I've been trialling letting it vent to atmosphere post catch can, not been having problems, then noticed one morning I had a small pool of oil on the floor & the catch can barely had anything in it.

Next, this 'pinging' / gear lash noise increased, I am now hearing it when I didn't ever hear it before.

This week EGT's have gone up by 60 - 80 degrees.

I've noticed the exhaust seems to be noisier, more drone coming into the cabin.

Fuel usage has increased.

Boost always sat at 15, dropped when off the accelerator, but almost always sat at 15, now it's sitting at around 5-6, it does go up when you put your put your foot down but hardly gets above 12.

Coming home tonight, in 4th at about 70kmh up a very slight rise, put my foot to the floor. Boost at 4, speed increased marginally, boost stayed at 4 didn't budge.

I've also noticed that it'll pull ok in 3rd, but when I shift into 4th it just dies.

This is intermittant as well.

138,000ks, ZD30, dawse & needle valves, EGR block, catch can, 3" exhaust.

Would it be any use to remove power to the ecu to reset it?

I'm thinking a vacuum leak??????

Well just tightened up all the intercooler pipes even the drivers side ones, cleaned the MAF and no difference.

The Dawse valve's been in for about a year. Did I hear that the springs in them can need stretching after some time as they go abit soft?

It just doesn't want to boost and the EGTs are higher for this vehicle than normal, give it a bit on the way up to 100kmh and it hits 500, it barely ever went near 500 in the past, even on desert trips.

I'm about at the limit of my knowledge here. All I can think to do now is replace the fuel filter.

I just read another thread elsewhere and the bloke had the same issue, he found his catalytic convertor was blocked. Hmmm, I have noticed an increase in in cabin noise from the exhaust.

the ball in the dawes valve has been known to push through the spring , might be worth checking . it happened on mine whilst setting it up .

I have zero experience on these but no one else is helping.. ;)

I think you might be onto something with the blockage.. extra exhaust pressure may cause extra blow by and raise your crankcase pressure causing your oil/catch can issues and it would definitely stop your turbo from spooling nicely.

Check your exhaust then if that doesn't solve it maybe check the turbo is okay and compression test.

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Originally Posted by nipagu7

the ball in the dawes valve has been known to push through the spring , might be worth checking . it happened on mine whilst setting it up .

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That issue was fixed maybe three years ago so I doubt that will happen. Unless he's bought the chinese copy of the Dawes.

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Originally Posted by 10G

Well just tightened up all the intercooler pipes even the drivers side ones, cleaned the MAF and no difference.

The Dawse valve's been in for about a year. Did I hear that the springs in them can need stretching after some time as they go abit soft?

It just doesn't want to boost and the EGTs are higher for this vehicle than normal, give it a bit on the way up to 100kmh and it hits 500, it barely ever went near 500 in the past, even on desert trips.

I'm about at the limit of my knowledge here. All I can think to do now is replace the fuel filter.

I just read another thread elsewhere and the bloke had the same issue, he found his catalytic convertor was blocked. Hmmm, I have noticed an increase in in cabin noise from the exhaust.

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That was also an issue with the first design of the Dawes around 6 years ago. Not for any after then.
Replace all the vac hoses would be my next step. Take the intake hose off the turbo and see if there is any play in the shaft. See if there is any oil residue in there too, and check the outlet side too. If theres more in the outlet than the inlet. The turbo could be on its way out.

Removed the dump pipe and gut the cat. Or the dearer option is to replace it in the hope its blocked, but I doubt it with the amount of K's you have.

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Originally Posted by nipagu7

the ball in the dawes valve has been known to push through the spring , might be worth checking . it happened on mine whilst setting it up .

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Thanks for the help mate.

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Originally Posted by 0-TJ-0

I have zero experience on these but no one else is helping.. ;)

I think you might be onto something with the blockage.. extra exhaust pressure may cause extra blow by and raise your crankcase pressure causing your oil/catch can issues and it would definitely stop your turbo from spooling nicely.

Check your exhaust then if that doesn't solve it maybe check the turbo is okay and compression test.

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Thanks for chipping in, no experience isn't a hinderance, sometimes it can help.

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Originally Posted by mudski

That issue was fixed maybe three years ago so I doubt that will happen. Unless he's bought the chinese copy of the Dawes.

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I got it off you amigo, so yeah, maybe the quality's not there ;-) A joke, I'm joking ;-)

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Originally Posted by mudski

That was also an issue with the first design of the Dawes around 6 years ago. Not for any after then.
Replace all the vac hoses would be my next step. Take the intake hose off the turbo and see if there is any play in the shaft. See if there is any oil residue in there too, and check the outlet side too. If theres more in the outlet than the inlet. The turbo could be on its way out.

Removed the dump pipe and gut the cat. Or the dearer option is to replace it in the hope its blocked, but I doubt it with the amount of K's you have.

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Dumb question. Are all the vacuum hoses the same size as in diameter?

Dumb question. Is it easy to spot a split IC pipe? Do they blow out or just crack?

Thanks for the help mudski, I appreciate it.

Higher EGT's are obviously due to much lower boost. And in turn, boost is where your issue is.


Re: Blocked exhaust / cat, enough to drop boost that much? .... I highly highly doubt it. Think about it, If this was the case the motor would sound like it's labouring (kind of like truck exhaust brakes) all the time and this alone would NOT cause for boost to drop that much.

Re: Noise / drone increased - I reckon this is simply due to lack of boost, and the motor is struggling to breathe enough. Almost being in a gear thats too high at lower revs and you get that "deep" drone effect..

Re: Fuel filter. I doubt it. Like the exhaust, fuel filter wouldn't cause boost to drop like that.



My $$$ is on a vacuum issue somewhere. It has to be. Something thats controlling the turbo spool isn't right.
Spend time checking all vacuum hoses , splits, blockages, ,check and recheck dawes / needle valves etc...

Also check the vacuum pump. Hows your clutch / brakes feel?

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Originally Posted by Hodge

Also check the vacuum pump. Hows your clutch / brakes feel?

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Clutch feels normal, brakes are always crap as in soft peddle that vanishes when you jump on it, which I think is normal for these things.

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Originally Posted by 10G

I got it off you amigo, so yeah, maybe the quality's not there ;-) A joke, I'm joking ;-)




Dumb question. Are all the vacuum hoses the same size as in diameter?

Dumb question. Is it easy to spot a split IC pipe? Do they blow out or just crack?

Thanks for the help mudski, I appreciate it.

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Yeah its been a while since I sold those....

If the pipe is split you would see oil residue. you have an aftermarket intercooler yeah?

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Originally Posted by 10G

Clutch feels normal, brakes are always crap as in soft peddle that vanishes when you jump on it, which I think is normal for these things.

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Yeah thats normal. Put the TB48 brakes on coupled with braided hoses and you will go through the windscreen when you hit the brakes. Lol

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Originally Posted by mudski

Yeah its been a while since I sold those....

If the pipe is split you would see oil residue. you have an aftermarket intercooler yeah?

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No, stock IC.

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Originally Posted by mudski

Yeah thats normal. Put the TB48 brakes on coupled with braided hoses and you will go through the windscreen when you hit the brakes. Lol

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Really? The brakes are the weekest link in this vehicle, when I jump on the pedal, I almost go to the floor, the pedal is shite.

Brought this first para comment of mine over from your noise thread mate.

If CRD check that the VNT solenoid is still plugged in. CRD require it to be plugged in when Dawes/needle installed even though VNT solenoid is bypassed(vac).
Also check vac lines as you said and at idle have a look and see if the actuator rod is in the up most position (lever hitting stop). Check to see if the actuator rod lock nut has not come loose an allowed the actuator rod length to increase. If too long eng will become very laggy and exhaust will get more of a throaty sound and higher EGTs. The witness line up marks on the the adjuster thumb wheel to actuator rod will indicate any movement. Best leave it alone if looks like it has not moved.

Following up from mudski comment, with your stock IC, take it off have a good look around for any oil residue top and underneath(bottom), and especially both tanks where crimped. Of course you will have a good opportunity to check/inspect boost hoses, hot/cold sides.

Vac hoses generally 3mm and boost side 4mm, think that is correct. I had Dawes, now use Tillix (both good) but the Tillix was installed by the guy that did my tune with ECU remap, the hose supplied by Tillix was 4mm and was slightly loose on the dampener (at vac take off) and this gave me poor spool/laggy until I got onto it.

There is a way to check your VNT boost behavior by bypassing the manual boost control but caution is req'd when doing this. This is how I got onto my spool/boost problem but other investigations first.

Your Dawes - is it the "Black" body and stenciled 3 Bar Racing? _ this is the one that is proven good IMO (also was supplied by mudski):

https://dawes-devices.com/collection...patrol-and-vag

Have you got a scan tool for clearing fault codes?

There are some good comments above by the other guys so no need to repeat.

Would not hurt disconnecting battery over night, but do not think ECU/limp fault is your problem at 15psi max boost.

What gauge you using to monitor boost? Had an issue with VDO boost line brass ferrule at cooler failing and had a significant impact on boost but I run 26psi.

Before you start pulling things down run the engine at idle and gradually unwind needle from the fully closed position and see if your noise stops.

just another longshot idea . how is your air filter . if it is blocked it maybe causing or contributing to the issue . i remember a situation years ago when someone put a plastic bag down a mates snorkel . it caused him a bit of drama until it was found .

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Originally Posted by Bidja

Brought this first para comment of mine over from your noise thread mate.

If CRD check that the VNT solenoid is still plugged in. CRD require it to be plugged in when Dawes/needle installed even though VNT solenoid is bypassed(vac).
Also check vac lines as you said and at idle have a look and see if the actuator rod is in the up most position (lever hitting stop). Check to see if the actuator rod lock nut has not come loose an allowed the actuator rod length to increase. If too long eng will become very laggy and exhaust will get more of a throaty sound and higher EGTs. The witness line up marks on the the adjuster thumb wheel to actuator rod will indicate any movement. Best leave it alone if looks like it has not moved.

Following up from mudski comment, with your stock IC, take it off have a good look around for any oil residue top and underneath(bottom), and especially both tanks where crimped. Of course you will have a good opportunity to check/inspect boost hoses, hot/cold sides.

Vac hoses generally 3mm and boost side 4mm, think that is correct. I had Dawes, now use Tillix (both good) but the Tillix was installed by the guy that did my tune with ECU remap, the hose supplied by Tillix was 4mm and was slightly loose on the dampener (at vac take off) and this gave me poor spool/laggy until I got onto it.

There is a way to check your VNT boost behavior by bypassing the manual boost control but caution is req'd when doing this. This is how I got onto my spool/boost problem but other investigations first.

Your Dawes - is it the "Black" body and stenciled 3 Bar Racing? _ this is the one that is proven good IMO (also was supplied by mudski):

https://dawes-devices.com/collection...patrol-and-vag

Have you got a scan tool for clearing fault codes?

There are some good comments above by the other guys so no need to repeat.

Would not hurt disconnecting battery over night, but do not think ECU/limp fault is your problem at 15psi max boost.

What gauge you using to monitor boost? Had an issue with VDO boost line brass ferrule at cooler failing and had a significant impact on boost but I run 26psi.

Before you start pulling things down run the engine at idle and gradually unwind needle from the fully closed position and see if your noise stops.

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Thanks for the help Bidja, much appreciated. My Dawse is a gold one, not like the 3Barracing one, got it from Mr Mudski about 12 months ago. I've got the torque app on my phone which I use for fault codes.

Funny thing, this all started about the same time the CEL came up on the dash. I checked that and it was for the 0401 code telling me about the EGR gasses, EGR is blocked and I get this coming up from time to time. Can having the EGR blocked cause any problems like this????

Can't remember the name of my boost gauge, but I checked it with the boost gauge in the Torque app and they were the same, so I'm happy that the gauge is OK.

Disconnected the battery last night, I thought, why not.

Thanks again.

it's on the check/replace list, thanks mate.

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Originally Posted by 10G

Thanks for the help Bidja, much appreciated. My Dawse is a gold one, not like the 3Barracing one, got it from Mr Mudski about 12 months ago. I've got the torque app on my phone which I use for fault codes.

Funny thing, this all started about the same time the CEL came up on the dash. I checked that and it was for the 0401 code telling me about the EGR gasses, EGR is blocked and I get this coming up from time to time. Can having the EGR blocked cause any problems like this????

Can't remember the name of my boost gauge, but I checked it with the boost gauge in the Torque app and they were the same, so I'm happy that the gauge is OK.

Disconnected the battery last night, I thought, why not.

Thanks again.

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Some prefer the brass body Dawes over 3 Bar Racing. Strip Dawes down, have a look at the ball and spring and see if the components are free of each other, clean it up and re-assemble. Do not play around with spring length.

EGR blanking plate alone will not cause this boost problem. There is a resistor mod to stop CEL light coming on with EGR blocked or do a ECU remap $790 posted and turn EGR off (higher boost pressure lower EGTs).. Sort current problem first.

You torque app, guess it clears trouble code properly.

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The EGR system consist of three parts: EGR valve, DPFE (differential pressure sensor EGR) and actuator solenoid.

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Check that the electrical connector to the VNT solenoid is plugged in....

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Code P0401 Meaning. ... This is likely due to faulty or clogged EGR valve or carbon buildup in the intake manifold or on the EGR temperature sensor.

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Can do a chemical clean to flush out crap in inlet manifold. Look for boost/vac leak issues first and check VNT actuator rod operation on turbo and the lever hitting stop

FYI, I have my Dawes 3Bar Racing valve here, could work some thing out if you want to go that way, but I would not rush at that option.

The reference to boost gauge (mechanical) was to eliminate any possible boost pressure leak at connections.

One thing - Before stripping down Dawes, use a marker and reference mark from adjuster to body (current set point) and the count the number of turns to disengage the threads as this will help to reset after clean.

Thanks for your help Bidja, much appreciate it.

Are these the 2 vacuum hoses under the IC? I'm pretty sure they are (see below). They seem to be in good condition. I cannot see where they plug into on the lower ends. Too hard to change I reckon, I'll leave 'em for now and if I get very very stuck for ideas I might swap them then.

Attachment 77963

This is a useful image as well. Hover over the part numbers and it tells you what they are:

https://nissan-europe.epc-data.com/p...l/223/14866VA/

What motor and is your IC oily

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Originally Posted by nipagu7

the ball in the dawes valve has been known to push through the spring , might be worth checking . it happened on mine whilst setting it up .

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Originally Posted by 0-TJ-0

I have zero experience on these but no one else is helping.. ;)

I think you might be onto something with the blockage.. extra exhaust pressure may cause extra blow by and raise your crankcase pressure causing your oil/catch can issues and it would definitely stop your turbo from spooling nicely.

Check your exhaust then if that doesn't solve it maybe check the turbo is okay and compression test.

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Originally Posted by threedogs

What motor and is your IC oily

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G'day TD. ZD30, IC is pretty clean.

Replaced 2 vac hoses and took it out and it went great, was back to normal. Gave it a bit more to check it out and it's gone to crap again.

Just about to check the dawse valve

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Originally Posted by 10G

Are these the 2 vacuum hoses under the IC? I'm pretty sure they are (see below). They seem to be in good condition. I cannot see where they plug into on the lower ends. Too hard to change I reckon, I'll leave 'em for now and if I get very very stuck for ideas I might swap them then.

Attachment 77963

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This solenoid operates the swirl valve, linked to EGR sys. Some block this off so the throttle plate in inlet manifold remains open always (when EGR is blanked off (EGR plate solid). This hose will be OK. Also with remap this is turned off along with EGR sys valve. There is a resistor mod to turn off swirl valve, have a read of this but continue with what U are doing going thru the list and note things down.

https://www.patrol4x4.com/forum/3-li...ve-mod-402763/

Craig(skegbudley) is a good hand.

Good you took your IC off how does it look and did U check the actuator operation at idle?

By the way have been doing lots of adjustment over last few months with actuator rod lengths (changes vac required to lift lever to hit stop), so I have rod measurements here that gives nom 14 inches of mercury (14 "Hg) which pretty ideal. Range is 11-15"Hg we will get to that if needed. I have a hand operated vac pump that I use to adjust rod.

Been in shed just got 3 fan belts off '99 Navara farm ute, one to pwr steering unit wrapped it self around the fan hub home stretch now...

Edit: Just read post U just did looking good mate

Thanks for all the help.

I',m not sure on readjusting the needle valve. You turn it until the actuator rod just lifts up & then back it off don't you?

Just started the car, boost gauge on 0 at idle, left for 3 mins, boost gauge drops to -12. Take for a drive and is crap.

If leaving dawes at 15 psi (prefer to go to say 16psi) but leave at 15 for the moment.

CRD can handle max spool so screw needle right in (closed),
Start engine and at idle start to open needle slowly, watch actuator rod and when it just start to drop (eg: lever just comes off stop grub screw), then turn needle back in about 1/8 - 1/4 turn.

This will give good spool and you can adjust further from there as suits.

When comfortable close needle fully. Find a hill that gives say 60-70% eng load, drive up in third gear @ 3000rpm and adjust Dawes (max boost) to where no limp occurs and then do needle adjustment as described above for spool that suits. Suggest max boost up around 16psi, some go higher but when under load conditions(towing) this is where limp will occurs.

Edit: Have to make sure your actuator is working properly, diaphragm maybe leaking. Just set it up as above have to go to shed for a while.

Well good news.

Replaced 2 more vacuum hoses, one was the boost gauge. Discovered the markers I had set for the needle valve when we first put it in, set the needle valve at that. Took it for a drive and all is well, it's flying. Gave it a good work out and am happy that it's sorted.

It's very responsive, boost peaks regularly at 16 and spikes up to 18, but it really is a spike, it immediately drops back down to 16.

EGTs are back in the safe zone, low 300s at 100kmh on flat, mid 300s at 110kmh. Got to around 410-420 at 90kmh up a hill in 4th. I'm happy with all that.

I think it's actually slightly more responsive. I did have some old dicky hose on there from the install, I forgot we ran short then and used some 2nd hand stuff, I guess it just got too old.

Thanks everyone for the great help, especially you Bidja, beers on me when we meet up mate, thanks.

And the -12 on the boost gauge is an electrical problem, I'll worry about that later. Boost gauge and Torque app on phone showed same boost once I fiddled with the gauge.

And that knocking, rattling noise has gone pretty much. :icon_victory:

All good mate.
Good mechanical boost gauges best. Remember CRD can handle max spool when you want a bit more pwr/spool (can use solenoid same as closing needle).

Glad you got it sorted mate.. too much going on with the crd's for my limited knowledge.

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Originally Posted by 0-TJ-0

Glad you got it sorted mate.. too much going on with the crd's for my limited knowledge.

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Yep me as well, that's why it's great to have some very smart & helpful people around on this forum that are happy to help out.