boost issues
 

Hi All

really struggling to find out why sometimes when i drive the car i get a 1 - 1.1 bar of boost then next time i accelerate i will only get 0.5-0.6 boost?

I have a scooby ecu chip, decat, k&n panel, walbro, sti 8 uk semi block, uprated oil pump, 1.2mm head gaskets, new rad, lightweight pulleys, replaced green maf, ngk pfr6b & tried pfr7b's, new coil packs about 12-18 mth ago, car is running really well & flew through its mot yesterday

Its driving me mad why no CEL light is coming on, no faults coming up when i do the plug connecting under the dash, i have tried different fuels, had new fuel filter, changed actuator (this has helped to get a stronger more reliable 1.1 bar of boost) & so on & so on.

Tried cleaning out the 3 port solenoid set up & also replaced & tried that but still no joy, restrictor pills are all ok, can not seem to find any split pipes. there is no spluttering or difference when it decides to only half boost, it just does? then 10 mins down the road, will be ok again.....

I am running out of ideas - only thing left is possibly the standard dump valve - could this be playing up? or could the walbro be playing up not fuelling right & car going into safe mode?

any help appreciated as this is driving me mental :mad:

Thanks

hiya m8 ive got similar prob .. mine will sometimes boost @ 0.8 then drop to 0.6 or even jus boost @ 0.3 ... im confused.com.

im gonna try cleaning the 3 port 1st an check the tightness of the actuator wastgate apparently it takes 6psi ( 0.4 ) standard to make it open. ( so i was told ) im probably wrong but if you take the solenoid out of line and run direct ( bypassing it ) you should get 6 psi boost constant ... i haven't tried it but it may help to diagnose it :)

let me know if it works :)