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Why cant I lower boost below 17~ lbs. ?

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6SENSE

Member
Joined
Jun 3, 2001
Messages
1,635
I think this started after replacing my WG vac Y-connector, which was just a plain old regular one from AutoZone, with the correct one with check valve. I remember being able to lower as low as 8? lbs. in the past. What is the problem?
I have the rod out as far as it will go without pushing the puck open, or loose, causing it to rattle.
 
Apparently, if it is not the correct Y connector from gm (the one the car came with) I believe that it will not work correctly. Without the stock Y connector to the wg, i was not able to adjust boost right
 
I changed the Y connector awhile ago. The reason this issue is coming up now is that I am having some KR issues and want to be able to turn the boost way down while I troubleshoot.
The "Y" that is currently on there is a stock GM one from a stock '85 drivetrain that I bought awhile back. The one that I had on there previously was the nonstock just regular, no cv, one. With the nonstock one (without cv) I was able to lower boost almost as low as I wanted. WIth the correct cv "Y" I am stuck running higher boost, which is great and fine with me, as long as I dont run into some KR issue as I am now.
I would put the nonstock one on there, which doesnt seem to "automatically" raise the beginning boost level up, but that is only a temporary fix. Doesnt the GM one help with spool up/acceleration?
Any ideas. Maybe the WG itself, and the fact that it has been cutdown?
 
If I adjust the rod out so far that it pushes the puck arm towards the pass. side and opens the puck during idle, is that a problem. I guess it would be the same as running with the wg unhooked, right? And when getting on it the wg will still pull the puck closed, so boost will go up? Hopefully lower than 17lbs. ?
 
I ran into the same problem recently. Got the car ready for the races and 4 days before heading out, the boost went from a rock solid 18psi to 21psi. No matter what I did, it will not change. I get absolutely no knock from this, but I would like it down at 18 for when I sell it. My 84 has the 87 computer and I even tried swapping the 85 'puter back in with a Lubrant chip vs the 87 w/ Thrasher. Nothing works to lower it.:confused:
 
Yeah, still have the problem. Let me know if you figure anything out.
As I stated above, rod is out as far as possible without going past the puck arm (towards passenger side). Boost actually creeps past 17. At least 18 as I saw it today.
 
Looks like it is time for a new waste gate controller. I suspect the diaphram has gone south. Apply vacume(preferably with a vac tester) to see if it holds vac. Later....Danny
 
Thanks for the suggestion. I will try that. Im guessing hook up the mity-vac to one vac port on the wg actuator and a vac gauge to the other? Apply vac and see if it holds?
 
well if it was fine before u added the new one Y and
check valve.


maybe its something to do with that?

make sure the plastic Y is going the proper way

straight side of the plastic y to the nipple on the turbo, and the curved side goign to the wastegate selenoid


why not try process of elimination?

maybe that check valve is somehow going the wrong direction?
why not try reversing that valve?
or you could even take that check valve off, and see if fixes it.
i know my car doesnt have a check valve.

also make sure all those hoses in that wastefate gate control system are in good shape and not leaking, and are all, ran to the correct places.
 
here a thought..........

if you still cant get the boost to drop down.


u could try running , the wastegate, "tuner style"


run a hose from the wastegate actuator right to the nipple of the turbo.

make sure your adjustable rod is backed out pretty far so it doesnt boost too high.

if you try this, and the boost is lower, i would say it definately has to be something to do with that new plastic Y , and check valve


its worth a shot,
its cheaper to buy a new rubber hose with no check valve or another plastic Y

then spend $30 something on a new wastegate selenoid from the dealer :)
 
Thanks, spent most of the day putting stuff together for the kids (the more cool gifts they get, the more work for you). I should be able to play with the car tommorow.

By the way, the check valve I was referring to was the one INSIDE the GM "Y". It is a check valve isnt it? The non-GM one that I had before did not have it.

I have some extra wastegates (actuators) and solenoids to try. Not sure which would be more likely the culprit, the solenoid or the actuator itself?
 
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