Reconditioned turbo = less boost, help!

mightydquinn

mightydquinn

Member
Hello, i've been having a boost problem for a while now, it would only boost to 1.2 bar and would drop to 1 while still accelerating with the actuator pipe off. I checked all the pipes and had it smoked to find i had no leaks. I took the turbo off expecting it to be an actuator fault, i had a bit of side to side movement in the turbo and the turbo specialist told me this was my problem. Anyway i got it reconditioned and also had a 360° thrust bearing fitted. Now i've put it all back together the most it will boost to is 0.7 bar, not happy! I've checked all my pipes again and they are all tight and all seem fine. Anyone else had a similar problem or got any ideas of what might be?
thanks Chris
 
mightydquinn

mightydquinn

Member
Yes, because side to side play is much worse than up and down play! I didn't have the actuator replaced as that was tested and was working fine! Would be good if these things fixed themselves!
 
PobodY

PobodY

Moderators
Staff member
Sounds like it's plumbed-up wrong to me.
Boost source to boost controller to wastegate actuator? Not the standard solenoid? - No harm in checking.
 
gtir_pimp

gtir_pimp

New Member
sounds like the actuator.how was it tested? is the boost controller turned on or bleed valve screwed open enough for more than 7psi? or is the pipe to the actuator still off?
 
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pulsarboby

Guest
pull the vacuum pipe to the actuator right off, it should then run unlimited boost, if not and it only boosts to around .7 bar then its either a weak actuator or cracked around wastegate penny on exhaust housing of turbo.

if it does hit unlimited boost (only try it once) then you have the thing plumbed in wrong somewhere!
 
mightydquinn

mightydquinn

Member
With the actuator pipe off it only boosts to 0.7 bar and iv just checked, the boost controllers still plumbed in right. Its jusr strange how it boosts less now than it did before i sorted the turbo out and there isn't a problem i can see!
Just done a fault code read and iv got a det sensor fault (34) could this be causing a problem and if so how would it limit the boost the car is recieving (with the actuator pipe disconnected)??
 
mightydquinn

mightydquinn

Member
pulsarboby said:
pull the vacuum pipe to the actuator right off, it should then run unlimited boost, if not and it only boosts to around .7 bar then its either a weak actuator or cracked around wastegate penny on exhaust housing of turbo.

if it does hit unlimited boost (only try it once) then you have the thing plumbed in wrong somewhere!
Click to expand...
Yes bob, with the actuator pipe disconnected i only get .7 bar boost. There was a small crack around the wastegate penny but the turbo specialist was very very sure this wouldn't stop me from been able to boost to my target of 1.2 bar! Its just strange how i could boost to 1.2 bar before i had it refurbished and the 360° bearing and now can only manage .7, i cant see my cracks causing so much loss, especially seen as they are the same now as they were before i took it off!
I am struggling to fix it though so all help and advice is good, thanks!
 
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pulsarboby

Guest
yes as martyn said above mr quinny

the det sensor wont help as it will put ecu into limp mode and retard ignition to protect engine, but it should still hit around 1.6 bar with the pipe disconnected (especially when engines cold), but the knock sensor will make it struggle to get there and feel like the car is holding back.
obviously you need to sort this prob aswell
 
mightydquinn

mightydquinn

Member
pulsarboby said:
yes as martyn said above mr quinny

the det sensor wont help as it will put ecu into limp mode and retard ignition to protect engine, but it should still hit around 1.6 bar with the pipe disconnected (especially when engines cold), but the knock sensor will make it struggle to get there and feel like the car is holding back.
obviously you need to sort this prob aswell
Click to expand...
Thats a right bummer, the whole reason of me taking it to a turbo specialist was so i didn't have to do the job twice. Would be so much better if i could find a problem with something else, guess i'll have to give them a ring again tommorrow! Is it the back pressure that forces the wastegate open then if it has a weak spring??
How do you get to the knock sensor, do I have to take the inlet manifold off? If i do, instead of taking that off would i be easier changing it while i've got the transfer box out?
thanks . . . Mr Quinny!!
 
gtir_pimp

gtir_pimp

New Member
mr quinny what will you say to the turbo specialist? did they take off the turbo an re-fit it for you? so youd be asking them to do the job again. i had to do mine twice and second time round i got the turbo off in an hour! so its not too bad. as unfortunately it has to come off to change the actuator.

as for the knock sensor use the search button and all will be revealed matey!
 
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pulsarboby

Guest
you can change the knock sensor with everything in situ thats assuming the big Y bracket is not fitted, its a pig of a job though at the best of times so if you have got to remove transferbox for some reason then do it then.

the actuator operates by positive pressure from the vacuum pipe, basically it moves a spring which then pushes the actuator rod forward and allows wastegate to open!
now if the spring is weak or its incorrectly fitted ie 'the rod isnt physically pulled over the wastegate pin' then the wastegate will either open prematurely or may be slightly open all the time which will not allow it to build up boost pressure
 
mightydquinn

mightydquinn

Member
No, i took the turbo off and refit it, they just reconditioned it for me!
Now the wastegate penny was shut flush, and was definately springing back and closing flush so no exhaust gases could seep past. I was just wondering if that could get forced open by the backpressure from the exhaust gases and thats why a weak spring in the actuator would be a problem as its not strong enough to keep it shut?
i will do the knock sensor when i take the transfer box out then, i have to take that out seen as the gearbox to transfer box seal and vice versa is leaking! More work!
 
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pulsarboby

Guest
no! if the springs weak then soon as the vacuum pipe alternates to positive pressure from vacuum ie...when throttles are open it will start to move the actuator rod early and this in turn will open wastegate prematurely.

thats why when you buy an aftermarket actuator you can purchase different spring strenghs with it which are interchangable.
 
mightydquinn

mightydquinn

Member
So on that theory if the vaccuum pipe is disconnected from the actuator and the spring has pulled the wastgate penny closed, which it did, then how would it be the actuator if nothing is connected to force it open?? Sorry to be a pain in the arse, i just really like to understand things before i take things to pieces! Cheers for bearing with me!
 
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pulsarboby

Guest
ok just read back through the thread again and you said it WASNT boosting to more than .7 with actuator pipe disconnected, so my fault for not reading that bit:der:

based on that i would say either:
1)the actuator is broken up completely inside and allowing the wastegate penny to flap around (try wiggling rod with a pair of long nose pliers to see if theres any movement in it)
2)the rod linkage has come off at wastegate end
3)the rod was not pulled over the linkage with enough pressure
(same result as no 1)
4) the crack in exhaust housing is making it lose boost pressure

it will be one of those 4 things
 
mightydquinn

mightydquinn

Member
Lol, now were on the same lines its all good! 1,2, and 3 are all ok, so i would say if its a problem with the turbo that means it would be the cracks which i know are there, but were told wont cause me a problem! What i shall do then just to take a leaking/partly blocked intercooler out of the equation too is fit the front mount steve pudney sent me today, i cant see it been a problem but would rather make sure before i go complaining to the turbo company an making an arse of myself!
Will be good to meet you at oulton park mate, always good to put a face to a name! Thanks for your help, i'll let you know when i find the problem!
 
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pulsarboby

Guest
yep oulton will be good as theres a few ive not bumped into before:-D

and as you rightly say you cant rule out a boost leak, although if all was ok before i wouldnt have thought it was your ic, but cars have a habit of the unexpected so it is a possibility.
 
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