ChoddyChod

My STi8 (with PPP) is suffering from low boost. It ranges from 10psi to 14psi. On the odd occasion I will be giving it some welly at 14psi it will all of a sudden jump to 20psi and stay like that for a short time (20 miles or so) and then go back to the 10-14 range.

Any ideas? I have cleaned the boost solenoid.

Thanks

mark6

i had the same problem with my wrx,all of a sudden starting boosting to 1.5bar,then suddenly went back to normal,hope you get to the bottom of this as it may help me pinpoint my prob as well,i was thinking it may be the actuator sticking?

ChoddyChod

Just been out again this morning. Its only getting to 10psi and an absolute max of 14.

1) What should the boost be on this car with PPP (20ish?)
2) What can I check?

Someone must be able to help with this one please?

ChoddyChod

Cleaned the MAF, took it out for a spin and getting 15psi max.

Can anyone offer any suggestions? Any at all?

Turbotits

iTrader: (2)

It hasnt been ecutek'd has it? and you have it on the low boost actuator pressure setting.

I say that cos mine will give me around 10psi climbing to 14 or 15 ish when on the low boost setting

ChoddyChod

No, its just Subaru fitted PPP.

Turbotits

iTrader: (2)

ok so i guess you cant really tell as there know phisical way to see and youve not long had the car. Try turning the ignition on and holding the throttle on the floor the switch the rear heated screen on and off.

This is how the ecutek toggles between boost settings. It may have something you dont know about

ChoddyChod

Thanks will try that and let you know.

gojonnyjo

iTrader: (1)

had the same prob, wrecked me head, checked fuel pressure, it was ok, got the Guys @ Ai Autosport to check her out, not getting the proper signal from the ecu to boost soliniod, possible broken wires, the cure, electronic boost controller, now the car is flying........



This is the one I got the lads to fit, is a wee bit costly and there are cheaper units out there, but HKS is the best.....

hope this helps mate

ChoddyChod

Well I tried the Ecutek low boost thing, but no difference. Im sure it hasnt got Ecutek, just PPP ECU.

ChoddyChod

Took it out this morning on a 3 mile drive with about 4 full boost blasts and it was 15 psi all the time except for a 5 second period where it was sat at 15 in 5th gear then jumped straight to 20!

Im confused.

ChoddyChod

Spoke to Roger Clarks last night, they got me in this morning to diagnose the fault. Turned out to be a MAF sensor, even though it wasnt showing as faulty on their computer.

Boosting back up to 19/20psi now and the grin is back.

Big respect to Roger Clark Motorsport for sorting it out at such short notice.