Not enough boost?

[joffo81]

Tweake, I understand that max boost is normally at 3000rpm but my boost will hit 10 or 11 or so at about 2000rpm and will not increase regardless of how high the revs go.

 

[Navmania]

I had what looked like a blown oil seal on my turbo but it turned out to be the hose clamps on the intercooler inlet line was loose and it was seeping oil out from there. That's one of the reasons I fitted the catch can inline with the breather.

Cheers.

 

[tweak'e]

Tweake, I understand that max boost is normally at 3000rpm but my boost will hit 10 or 11 or so at about 2000rpm and will not increase regardless of how high the revs go.

well that certainly sounds like there is a problem.

plenty of things to check.
any intake leaks, common ones are the rubber joiners. take them off and clean them. oil from blowby can seep in and unstick them which helps them leak.

if egr is blocked check its not leaking at the blanking plate.

exhaust leak, egr is prone to cracking especially turbo end.

make sure butterfly mod is done ok and butterfly's stay open.

test waste gate. possibly its stuck open.

check turbo, is it easy to turn ? any damage on the blades?

make sure nothing is blocking pre turbo air intake.

 

[DieselTuner]

Having a slight drip or weep of oil around the turbo is completely normal on most turbo cars.

Alloy used in a compressor cover is actually a porous material, and when a liquid sits in there for an extended period of time it will seep through.

It is especially noticeable on vehicles that have the engine breather higher than the turbohcarger. The oil vapor tends to condense always run down to the lowest point and pool there.

Vehicles like a wrx, evo, gtr or most turbo petrol cars all have the engine breather basically parallel with the turbo, and they dont suffer the problem as a result.

 

[joffo81]

Thanks agin Tweake,

I will try to investigate some more this weekend. Butterfly mod is fine and egr is blocked and not leaking. Its difficult to check the egr pipe behind the engine but I can't see any sooty marks. No visible turbo damage and it spins freely. I'll check my air filter and joins in the intake but my snorkel is well sealed. My catchcan should eliminate blowby.

How do I test the wastegate to see if its stuck open??

 

[tweak'e]

good question. disconnect the arm and see if its nice and smooth. check that there is spring tension and with it disconnected the arm should not quite reach the wastegate arm pin.

can you take a pic of the turbo? just compare to others in case the housing has been rotated which changes how the wastegate operates.

 

[tweak'e]

in case someone hasn't already mentioned it, try another boost gauge.

 

[tweak'e]

the other thing is connect a boost gauge directly up to the turbo. this will also disable the wastegate so don't run it to much or it will over boost.
this will tell you if the turbo itself is making enough boost.

if you can't get full boost at the turbo then its either exhaust leak or turbo/wastegate problem.

 

[joffo81]

Hi Tweake,
I have disconnected the wastegate pin from the actuator?? arm (not sure if that's what its called) by removing the circlip. The wastegate arm moves easily but does jam if I push it all the way towards the firewall. Should I be able to move the actuator?? arm?
There is no spring tension in the wastegate arm but I can't move the arm that it was connected to.
The pin won't quite line up to refit the circlip so it looks like I have to loosen the actuator fastening bolts.
Any more info about the wastegate as I am unfamiliar with how they work!

 

[tweak'e]

Hi Tweake,
I have disconnected the wastegate pin from the actuator?? arm (not sure if that's what its called) by removing the circlip. The wastegate arm moves easily but does jam if I push it all the way towards the firewall. Should I be able to move the actuator?? arm?
There is no spring tension in the wastegate arm but I can't move the arm that it was connected to.
The pin won't quite line up to refit the circlip so it looks like I have to loosen the actuator fastening bolts.
Any more info about the wastegate as I am unfamiliar with how they work!

that sounds good.

wastegate has a 20lb spring so its frigen hard to move. the pin should be 3-5mm at guess short of the hole in the arm. thats the wastegate pre load.
if you can't move the arm then loosen off the bolts, hook it up, then do the bolts up.

 

[joffo81]

well that certainly sounds like there is a problem.

plenty of things to check.
any intake leaks, common ones are the rubber joiners. take them off and clean them. oil from blowby can seep in and unstick them which helps them leak.

if egr is blocked check its not leaking at the blanking plate.

exhaust leak, egr is prone to cracking especially turbo end.

make sure butterfly mod is done ok and butterfly's stay open.

test waste gate. possibly its stuck open.

check turbo, is it easy to turn ? any damage on the blades?

make sure nothing is blocking pre turbo air intake.

Thanks again Tweake. I put the wastegate arm back together without a single swearword!

I have checked everything on the list above except the EGR pipe which is not very accessible.

If I could get my hands on a boost gauge from somewhere how would I go about fitting it directly to the turbo?

Here is a photo of my turbo with the heat shield removed.

 

[tweak'e]

looks like you have an intercooler.
need to put a gauge before the IC and see what the drop is across it. had someone who wondered why he got low boost, turns out it was a rag stuck in the cooler!
also it would pay to make sure existing gauge reads correctly.

you can unhook the waste gate hose and connect the gauge there. just remember that disables the wastegate!

 

[joffo81]

Ok that makes sense.

The intercooler is a DIY job mainly for piece of mind rather than performance gain. Its a micro cooler that I mounted where the air pre-cleaner used to be. I'm sure I was getting low boost before I installed it.
I have a VDO gauge (good quality) in the pillar pod and it used to peak at 15PSI so I am still puzzled! The puzzling thing is that the boost is variable. On my way home from work on friday max boost was 14PSI but today I could only get 11 out of it.

So if I can get my hands on another boost gauge and put it directly on the turbo should I just drive it carefully so it doesn't overboost and see what the gauge reads??

Haha - the old rag trick! I left a rag in my intake when I sealed up my snorkel but I remembered just before I started the engine! I checked my air filter today and it wasn't too dirty.

 

[tweak'e]

don't drive it with wastegate disconnected. just rev it up in nuetral. if i remember right you will hit 15psi about 3500rpm.

borrow another gauge anyway. good to double check and see the drop across the ic.

if boost is coming and going it could be a leak thats opening up a very weird blockage or loosing fueling.

 

[tweak'e]

can you disconnect the DP chip?

 

[joffo81]

ok thanks again Tweake. I wasn't sure if the turbo would produce a boost reading in neutral.

I can easily disconnect the DP Chip. I might do that before work tomorrow and see how it drives.

 

[joffo81]

I disconnected the chip this morning and there was no change to the problem. On the way to work max boost was 10PSI and about 11PSI on the way home.

I am working on borrowing a boost gauge to check pressure at turbo.

How can I check that the buttlerflys are working properly?

 

[Forefront Industries]

might be better to test using a T piece to a second gauge to the wastegate line line and check they are reading properly by driving it....easy enough to get a cheap t piece from somewhere

very strange that its variable.....a leak is a leak you would think ?? it would be there all the time....unless its a fuel delivery issue and the less fuel is equaling less boost or something weird

i guess the other idea could be failing actuator sometimes it seals inside the diaphragm sometimes it doesnt? but you would typically expect it to go the other way...High

few ways to stop boost

restrict intake to compressor
restrict outlet of compressor
restrict exhaust outlet eg:wastegate and CAT blokage
restrict exhaust intake to turbine housing
possibly fuel related

its not something weird like the bit of foam in your inner guard blocking the airbox intake from the guard ?? or rats living in a snorkel?

 

[shane75]

Hi all,I have an05 zd30 nav with 3inch exhaust,snorkel,land cruiser airbox &egr mod and I am only getting 12psi of boost.i'm chasing possible problems and solutions or is that acceptable?

Turns out the boost gauge wasn't set correctly from factory so now that is fixed it is reading 17 psi maximum boost!!! Cheers for all the responses.

 

[tweak'e]

thanks for the feedback