What i got; 2003 cummins 305/555 automatic, tst, boost elbow

Problem: truck will not boost over 30psi, no smoke whats so ever.

What i've tried.. turned the boost elbow all the way in and out, pulled the waste gate hose off, checked the waste gate itself to ensure free movement, and plug the boost elbow port with a solid plug. turbo spins freely, no movement in the shaft. I have turned the tst all the way to 4/4 and it does not smoke, and will not boost more than 30 psi. It makes boost to 30 very easy but just stops at 30. Talked to tst and they report that the truck should make boost over 40 and the guy i purchased the tst from reports he had boost up in the 40's. Also the exhaust gas temps never get that high less than 1200.

What do you guys think?

 

anyone????????

 

you are on the right track checking the waste gate...must be something there...OR your defueling at 30...check your defuel settings on the tst remote.

 

Several things come to mind, one is the accuracy of the boost gauge and are you running the stock lift pump. Could be the lift pump can't deliver enough fuel to the CP3 during heavy duration.
But don't feel bad, I'm only able to get about 32psi with the SMARTY and the boost elbow. Note that the stock turbo doesn't live very long when the boost goes past 35psi.

MikeyB

 

is there any way to check the lift pump for accuracy or correct psi?

 

You can get one of those boost foolers off quad. But the 03's and 4's had a smaller turbo than the 04.5 and newer. So I do not think you will get much out that turbo.

 

cant do that. 04.5+ truck use electronic waste gates....03-04 don't. thats why he has a boost elbow.

 

To check the lift pump a fuel pressure gauge is needed.
www.genosgarage.com is a good place to shop for gauges.

MikeyB