advise

iTrader: (3)

Did a 3rd gear pull and at around 5k it drops from 24 to 15psi
Did this 3 times
Just changed the belt
would the bypass just open mid pull or belt slip?

TStone

iTrader: (2)

Belt slip could be possible, but it wouldn't cause that big of an decrease in boost.
Your bypass valve could possibly be messed up. That's kinda what it sounds like to me

advise

iTrader: (3)

Ya and it's a smooth 15 psi
Not fluttering like belt slip would

TStone

iTrader: (2)

Ima say bypass valve then

advise

iTrader: (3)

Any way to test it?

TStone

iTrader: (2)

See if there's any play in it.. other than that, no not really

There should be very minimal play at max




and by "it", I mean the metal shaft/rod







Edit: Ah yes, forgot about that VVVVV
You can plug the port coming off the bypass solenoid and the one coming off the bypass valve and see if it fixes your issue

Powell Race Parts

iTrader: (3)

pull the hose off the bypass and do a run.

Powell Race Parts

iTrader: (3)

by pass valve shafts can seize especially if meth has been put through the blower. In my experience they seize open. If you have a vacuum leak at the IM, the valve will open and close at idle and generally misbehave... if you pull the hose, just stick a plug in it, the valve dont care, the solenoid does and you dont want a vacuum leak there.

advise

iTrader: (3)

Did a run works fine If it happens connected pull the hose on the valve
As for the shaft being stuck i can actuate the valve by hand no problem
My idle has been surging but i believe it's do to the winter blend e85
All my vaccum lines look fine and connected

TStone

iTrader: (2)

You should be able to actuate it.. But you shouldn't be able to move it back & forth & round and round. Kinda hard to explain the motion

advise

iTrader: (3)

Moved it around seemed good
Did 2 pulls no problem
Hope it doesn't happen again
Only a week or two before she gets garaged for
A little winter build cams springs balancing shafts and 1000s maybe a ported head

574

iTrader: (5)

What cams are you going with?

advise

iTrader: (3)

zzp stage 2

574

iTrader: (5)

Nice, I'll be waiting for a review on those lol

advise

iTrader: (3)

Still.the same problem what hose am i removing

rivaladore

iTrader: (7)

The hose that goes to the bypass valve. Take the hose off right there but leave it attached to the solenoid which is to the right of the valve cover. Plug the hose don't worry about plugging the bypass valve nipple. You plug the hose so there's not a vacuum leak at the bypass solenoid.

advise

iTrader: (3)

Gotcha and if I have no boost loss my valves bad

Area47

belt slip. get a larger tensioner.

advise

iTrader: (3)

I have a larger tens. And a phenolic spacer
And it seems a little odd that i had the same pulley
Size (2.7) on my m62 for 2 years no issue and out the blue this happens

Area47

weak tensioner then.

advise

iTrader: (3)

changed my belt from a dayco i got from work to my original gm belt
problems fixed 25psi all day

Powell Race Parts

iTrader: (3)

^^^ u said it was not the belt like 200 posts before...well. glad u got it fixed. lol