tweenierob

i thought i had a problem with my boost solenoid so i replaced it with a bleed valve, made a difference BUT, i thought that i would raise the boost to 14psi from 11psi... which has highlighted a problem, if i wind the bleed valve out it makes no difference to the level of boost.. i thought that this may be due to the size of the bleed hole not being big enough. So i disconnected the wastegate pipe altogether and gently pushed the throttle, which brought the boost up to 11psi, i then pushed the throttle a bit harder and still 11psi, no matter how much i press the 'go' pedal the boost wont go over 11psi WITH NO WASTEGATE PIPE ON, whats all that about?????????????????????????
i've been left thinking that the actuator may be faulty and will not stay closed after 11psi has been reached.........
?? ROB ??

what am i doing wrong??

[Edited by tweenierob - 4/19/2002 9:06:47 PM]

pob on the job

Short but sweet question but might light a bulb..

is the wastgate stuck (partially) open?

tweenierob

Pob, not sure mate.......
think sundays mission is to take off the heat shield and investigate?????
any other ideas appreciated!!!
cheers mate
Rob

tweenierob

ttt

skiddusmarkus

Do you mean it won't boost over 11psi when stationary or whilst moving on the road?If it's while stationary the boost won't go very high as it isn't under load.

cryptwalk

Whats that in bar? Whats the formula for converting psi to bar?

john banks

14.5 PSI = 1 bar.

If the wastegate pipe is disconnected and it won't boost higher it suggests the actuator is floppy or as pointed out before the wastegate is not closing, or potentially a turbo problem.

I don't know what turbo yours is, but most TD04s would go well over 25 PSI and possibly over 30 PSI and damage themselves and/or your engine with a disconnected wastegate at full throttle in the midrange. This is obviously very different to what you are seeing.

tweenierob

cheers for the replies people,
there is a slight 'bottle top' noise when the boost first comes up, say 2-4psi.. i have removed the dump valve but it has made no difference, so i am left thinking that the cause may be the wastegate being open all the time, i am hoping that it is not due to a cracked housing or wastegate but.... can anyone suggest a way of testing either the actuator or wastegate without removing the turbo, perhaps remove the downpipe.
will i be able to see the wastegate if i remove the downpipe???
many thanks for all your help
Rob

john banks

You can remove the turbo heatshield and access the actuator, remove it from the wastegate and check it moves freely.

tweenierob

oh well, took the heatshield off today and had a look at the actuator, i took it off of the wastegate arm and pushed the wastegate closed, it matched up exactly with the hole on the actuator arm, this led me to believe that the wastegate is not stuck open....
i then pulled the actuator arm to see how much pressure it took to make it move (not that much!). once i had put it all back together i let the car warm up and took it out for a spin, at first it was only giving 7psi (0.5 bar) and after about 5 mins i noticed that the boost has risen to about 9psi (0.7 bar?)
this was after it had been boosting 11psi before i pulled the actuator......
i'm hoping that i have found the problem now...
but would like anyones comments/help/ideas???
thanks people
Rob

john banks

You could consider measuring boost at different points to see if there might be a leak? Say you could measure at the turbo outlet. I don't know much about dump valves, but could yours be leaking?

tweenierob

John, i have removed my dump valve and tried my boost gauge at the turbo and the manifold, i am getting the same reading at both points...
Rob???????????