slight boost problem :S

[Hugh Janus]

Pulling out of a small slip road earlier car went like a rocket got to about 75 and eased off slowed to about 60 and went to overtake someone and got stuttery boost ( higher rev range) then looked at the avcr and safc peak settings and found:

Inj: 99.9% ( injector duty cycle)
Bst: 1.39mmhg (1.39 bar more or less)
Sol: 75%


Knk: 143 ( knock,det ect)
Afl: 75%
rev: 6666rpm
Thr: 72%

Anyone got any ideas? Of normally runs 1bar max, I'm guessing a small pipe has come off, can't check right now

another set of figures:

Inj: 65.9%
Bst: 1.15
Sol: 72.6%

Knk: 17
Afl: 49.2%
Rev: 4705
Thr: 55%

the thing is its flying up to silly boost with no effort, as you can see with the throttle half open its going to 1.15bar it only stopped there because i lifted off

i had for a very very long time a fairly major boost leak, that im guessing started life as a small one, when i had it RR'd (i wasnt aware at the time it may have had this leak) but the bloke commented saying it was leaning out slightly top end and made some adjustments on the SAFC...could it be he also increased the boost (it wouldn't boost above 0.9bar at the time)
if so now its all tight and ship shape the boost is now set too high

would also explain why recently a bloke in a Astra coupe turbo driving seriously up my arse commented by pulling next to me after i gave it a few beans (up to the speed limit and safely i may add) telling me how fcuking quick it was (i thought at the time he decided to pull back)

one more set:

Inj: 64.5%
Bst: 0.95
Sol: 65.1

Knk: 17
Afl: 46.5
Rev: 4444
Thr: 43.6


im liking the boost, but having an engine fail on me at the moment, is the last thing i need financially (not that ay time is really a good time)

anyone got any ideas?

ideally i would get apt to look at it, but at the mo, the car is used once a week if its lucky, becuase im currently flying up and down the country working 16+hrs a day at the moment

[maff]

What are you using to control your boost pressure? Sounds like its not doing its job so your wastegates not opening, and you're getting as much boost as the tubbie can give, this in turn maxes out the injectors as they try and pump fuel in to match the airflow, and it dets its tits off.

This would explain, higher boost, 99% duty cycle and lots of knock.

Either that or the wastegates stuck shut, but thats weird.

[duncan]

Check the pipe from the solenoid to the actuator. As Maff says it sounds like that is off completely.

[Andy916]

Yup, check those small pipe connections, and zip-tie back on to prevent recurrence. I had similar symptoms due to the same, although that was on a '95 WRX which hit fuel-cut before it hit 1.3bar (very abrupt, feels like you're going to headbutt the windscreen!). Went like a rocket up til that point tho :-D

Am guessing your car has a higher fuel cut threshold.

[Hugh Janus]

sorted was indeed a pipe from the boost solenoid (AVCR) had popped off

i wish all boost leaks where that easy to find and rectify

[duncan]

:thumb: