[J Ferguson]

Just wondering what yall think. When I hit WOT my boast goes to 35 psi but then immediately drops back down to 28 psi or so. it will not stay pegged at 35 psi. could this be a boost leak or another problem?

 

[tryNto]

:welcome:

First, Truck info always helps.

Could be, but may not.

 

[J Ferguson]

Thanks
06 SWR, 3500, mega, 6 speed manual, southbend double disk clutch, 4x4, tst powermax cr, Aug. 05 build date 252,000 miles.
Factory turbo came apart this past Jan. I replaced with a new factory turbo started having problem soon after.

Ive looked up all the different ways to do a boost test I was just wondering if I was chasing my tail before I tried a boost test

 

[rdnckhauss]

Waste gate. Is probably opening up.

 

[J Ferguson]

I assumed the waste was operated by the TST programmer since I can control my boast from 30 psi to 40 psi

 

[J Ferguson]

Waste gate I mean

 

[rdnckhauss]

Im not sure on the electronic controlled ones. But, simple try (may throw a code) unplug the controller, second find someone with a smarty near you. I will also suggest searching the forum and maybe posting in the performance mods section. I'm not sure on TST does it move the opening pressure or just set an alert when you reach a set pressure?
I know you're a fairly new member. If you scroll down the main forum page fine you State chapter and look around there. You can connect with local people. Also click the user cp link on top bar and you can put you truck details in you signature so it post on all your posts like mine and others you see.

 

[J Ferguson]

Thanks for the info.. I bought the truck in 07 with 23,000 on the odo. The previous owner had already installed the TST but I have all the instructions. When I replaced the turbo this year I read through the instruction to see if any waste gate mods were needed and didn't see anything. It doesn't throw any alarms it just doesn't alow boost to go over set point. I have it set at 36psi I can turn it up to 40 psi and it will hit it but same thing immediately drops to 28 and holds. Maybe just a product of 252,000 hard miles.. Lol

 

[cerberusiam]

WG controller is opening, thats normal programming for it. Take a pair of vice grips and pinch the boost reference hose closed and you will see and hold all the boost you want.

 

[lpennock]

Mechincal Wastegate on a stock turbo is set at 24psi. The computer bleeds off boost signal using the wastegate solenoid. The computer allows boost about 28psi for short periods but then backs the boost down to 28psi so your Wastegate is operating normally.

If your TNT doesn't have a boost fooling function you will need a Boost Fooler to allow the turbo to run above 28. Clamping off the WG sense line will also allow you run more boost but it can also cause you to get a CEL for over boost occasionally. Switching to a Smarty will allow you to run a higher boost as a Smarty extends the MAP table so the computer doesn't try to step the boost down.

 

[J Ferguson]

Thanks for the info guys.
My TST does control boost I've always been able to hold boost at 35 psi or even 40 if I set it for that with the controller. I didn't have this problem until I replaced the turbo earlier this year.

 

[cerberusiam]

WG controller is probably bad., Crimp the boost reference hose to verify it will make and hold boost then you can decide if you want to replace it or add a fooler and a boost elbow.

 

[J Ferguson]

Thanks I will try that