Car history first...
MY99 UK turbo, h+s de-cat, K+N filter, samco hoses, John Banks mapped (Tek2.5) ecutek ecu, standard DV etc.

The car has just had it's 52k service, and up until today has always run with no problems, but after a trip to me local garage I noticed that the boost guage was reading upwards of 19psi if I planted the throttle, then fluctuating around until it seemed to settle. However, as a check I found a quiet stretch of open road and went through the gears from second.
I found I am pulling around 16psi in second, 17 in third and in fourth gear the car hit fuel cut at around 18.5psi. (I didn't bother with fifth because I know what overboost can do!!) Tried another run and same thing, also as I change gear as soon as I re-hit the throttle the guage swings straight up to around the 20psi mark! This happens in every gear.

Could this be;
a) sudden cold weather from the hot days recently.
b) Bad batch of petrol causing knock.
c) Over-fill of oil from the service
d) A.N. Other problem that I am not aware of??

Main reason for posting is that I won't have time to strip it before japfest on Sat and I don't really want to blow the car to smithereens before I get there!!!
Any ideas welcome guys.....

Also, for future knowledge will a dawes MBC be worth getting to prevent this ever happening again??

 

COme on tecchies, I was supposed to be on track tomorrow and I can't unless I can fix this!!!
Checked the oil this morning so I can definitely rule that out as a cause by the way.
Plus I have a bottle of millers going in this evening to rule out the fuel causing it to run lean.

 

Have you tried cleaning the boost solenoid? Connect 2 green connectors together under dash and turn ignition on (but not start engine), and boost solenoid will click repeatidly (Careful as electric cooling fan will run also)allowing a good clean when cleaner is sprayed in to it and pipes.Use Brake cleaner - spray into rubber pipes.

Also, have you looked at waste gate actuator/arm - you may need to remove the turbo/exhaust heat shield (about 6 bolts) to get to this reasonably. Check that actuator arm pin is not loose, and that arm moves mechanism freely - mine was jammed/stiff, and freed using WD40 (my symptoms were overboost intially then later little or no boost). smooth movement observed by manually moving arm after spraying point where it enters actuator several times while moving arm at same time.

Tried both of above, and car has run well since

Added: My Car UK MY99 TSL decat, had JB 2.5 ECUtek, now TSL custom map.
My overboost was similar 20psi+, then little/no boost the next day. Was advised above, which worked for me

Hope this helps

Graham

 

FOund it.
Split hose from the turbo to the boost control valve.

 

Glad to hear you have it sorted!

Graham