Can a boost leak cause knock when you are driving in vacuum.

Is the car misfiring at all? If its misfiring it could cause the car to think its knocking but I wouldn't be worried about it actually knocking. Could be just vibration from misfiring.

CRAIG

30-40 counts from 2500-3000 rpm. no misfiring. timing is anywhere from 30 degrees to 20 at higher knock. my o2 trim is running 95-105% in this area..

If it was a huge boost leak couldnt it be running really lean?

my though would be rich.

No, ONLY if you are boostin will you be runing rich cause the metered air will be PUSHED out of the pipes, when you are in vacuum unmetered air is being PULLED through the leaks.

Or so I think

makes sense

Im sure someone will let you borrow a wideband if you want.

nobody has one down here where i am.

You in Iowa?

winona

That like 2 hours south of here?, what you doing sunday?

i dunno why i would need a wideband for that. im going to boost leak the system this weekend when i change my oil.

oh, i thought you were trying to tune for some reason

i have tried tuning and the knock is insane. thats why i was asking my question
;)

Well do a boost leak test yo.

go to home depot, build leak tester, answer own question

good work!

i wish we could drive in a vacuum. we'd be fast as shit

defeats the purpose of having this website doesnt it?

the only time i will be able to do a leak test is saturday, which i have the tester. so whats wrong with asking before hand?

Well mb if it ran lean enough it could, I dunno =/

so far i have done a boost leak test and have found a nice one at the biss o-ring so i replaced it and checked. that part is good but i noticed around my bov flange that i have a small pinhole that i also need to take care of. hopefully it fixes it. :bounce:

no dice..

still have the problem?

yeah i still do. the next things i am going to try is to put back on the stock fpr and a new knock sensor that i have.

What do you have done as far as your fuel system? Are you running a stock MAS? What do you get for vaccum at idle? I get knock sometimes at partial throttle. I can tune low throttle better but for the most part I do not care about it. You are having problems tuning WOT?

i have a walboro 255 fuel pump, afpr, 550cc injectors, 2g maf. my troubles are in my lows. from 15-20% throttle. my vacuum at idle is 20in.

Does the car seem to run fine at low throttle, you jsut see knock on the logger? If so, I would leave it alone. Have you tuned low throttle trims to 100% yet?

yes they are all good. the knock goes ballistic, car still runs smooth and the timing gets pulled.