Wont' boost EGTs up out of ideas?

[10G]

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??????

[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.

[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 .

[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.

[mudski]

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 .

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

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.

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.

[10G]

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 .

Thanks for the help mate.

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.

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

[10G]

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

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

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.

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.

[Hodge]

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...

[Hodge]

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

[10G]

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

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.