Low boost issue

[GNXV6]

Hi I did a search on this and could not get a clear answer. No matter how tight I have the actuator rod and the RJC boost controller all the way screwed down I can only get 14-15 lbs of boost. The car sat for 15 years after I rebuilt it but I never got on it since then. Scanmaster readings are near perfect ranges. I have a te 44 turbo and I believe I have ATR 3inch down pipe. Puck lever seems to move freely not sticking. I had the stock turbo before the 44 and boosted way above that. I did notice a dent on my crossover pipe. No exhaust leaks. The actuator rod feels easy to pull up to the puck lever. Can a weak spring cause this or the puck not sealing right?

Thanks all

 

[dank GN]

Okay do you understand how the controller controls boost? Basically there is a bypass hole that a flap covers . Now there could be several reasons you can't raise the boost . One of them is the flap that covers that bypass could be Not perfectly covering the bypass hole . I would check that out .

 

[GNXV6]

Okay do you understand how the controller controls boost? Basically there is a bypass hole that a flap covers . Now there could be several reasons you can't raise the boost . One of them is the flap that covers that bypass could be Not perfectly covering the bypass hole . I would check that out .

Thanks Dank, I removed the boost controller and I see a pin hole on the 90 degree elbow. I took the rjc apart but I do not see a flap. just a steel ball and spring came out. I was able to push air through the elbow and I felt air coming from the pin hole. Anyways I kept the rjc off and connected the Y and solenoid to factory connections and still having the low boost problem. Anything else?
Were you talking about the wastegate puck on my downpipe?

 

[bison]

You need to assess the wastegate. The size of the bypass particularly. Re-surfacing of the exhaust housing is often needed. After -.010"

After .015"

The size of the hole needs to be assessed also. Too big and it will cause problems. The one above is a little too big for what he's doing. Plate for re-sizing

Sent from my iPhone using Tapatalk

 

[Nick Micale]

The Scanmaster has nothing to do with boost, but the puck and actuator does control boost.

After 15 or more years the actuator is subject to fatigue of the internal spring and leaks.

My first simple test, cheap and quick in this case, I would take some wire and wrap it around the actuator leg so the puck is tightly sealed to the hole in the exhaust housing.

A road test will tell if that if that is the issue, but be careful driving so the boost does not spike too high like 25 psi!

 

[GNXV6]

The Scanmaster has nothing to do with boost, but the puck and actuator does control boost.

After 15 or more years the actuator is subject to fatigue of the internal spring and leaks.

My first simple test, cheap and quick in this case, I would take some wire and wrap it around the actuator leg so the puck is tightly sealed to the hole in the exhaust housing.

A road test will tell if that if that is the issue, but be careful driving so the boost does not spike too high like 25 psi!

Wow good ideas here. I'll try that. then I'll look into what Bison posted. Thanks for the replies!

 

[1986 Buick GX1]

The actuator rod feels easy to pull up to the puck lever. Can a weak spring cause this or the puck not sealing right?

Thanks all

Assuming you have an adjustable wastegate actuator rod.
The looser (longer) the wastegate actuator rod is the easier it will be to connect to the lever and the lower the boost will be.
The tighter (shorter) the wastegate actuator rod is the harder it will be to connect to the lever and the higher the boost will be.

If your spring is rusted and weak you'll get the same low boost condition as well.

More than likely the exhaust pressure is blowing the puck away from the hole and giving you lower than desired boost, or the puck is not sealing as mentioned earlier.
Keep after it, you'll get it.

 

[belsie]

Seems like testing the actuator is in order or borrow a known good one & run it to confirm if possible?

 

[ILikeSix]

I think testing it is definitely in order... The wire it shut technique will tell you if the actuator is the culprit but there's a couple more tests that I've used. First and easiest, if you actuate it open on a cold motor with you fingers, is it firmly on the seat? I've read there should be 9lbs of pull but that's kinda hard to quantify. Second test is to hook a hand vacuum pump to the actuator nipple, it should open under vac but more importantly STAY open and not lose vacuum while at rest.