Boost gauge readings

[Goose57]

Hi all I have a new GM 8 turbo on my new Optimizer. I can’t remember what my boost gauge readings were on my old stock one that came on the truck. I’m not sure this one’s working properly. When under a load going up hill no trailer I floor it and it jumps up then immediately drops to zero before getting back out of it.Before I had a turbo master on the old turbo and can’t remember it doing that. Thanks.

 

[Paveltolz]

Doesn't sound like you're putting much of load on the motor to bring on any sustained boost. Also, the motor is new, stronger and that can manifest itself in many ways to include change in 'normal' boost readings and that goes for the turbo.

What happens on a downshift and a little more sustained throttle?

As for alleviating concerns about the gauge, I'd start with the sender and how well it's sealed before condemning the gauge itself. My Isspro set up was a little wonky and I was able to sort it out with a new sender vs. replacing the whole set up (years later I swapped over to autometer, had an issue with the EGT sender and, again, new sender sorted it out).

If you still have the old turbo you could always swap it in but, I'd still focus on the gauge set up.

 

[dbrannon79]

it all depends on how the boost controller is setup. are you still using the turbo master or are you allowing the PCM to control boost? check all vacuum lines from the pump to the solenoid and from the solenoid to the turbo. with the engine idling you should not be able to move the rod from the actuator on the turbo by hand.

if still running the turbo master, forget all I said above and check the plastic tubing connections. I learned rather quickly the tinyest leak on the tubing will make a mess of things. also if the compression nut is over tightened it will collapse the tubing too.

verify turbo hose clamps are tight as well as the upper intake gasket is sealing too.

 

[dbrannon79]

one other thing is if you are running the factory setup with the solenoid. you can test the solenoid's function with the GMTDscan as well as look at the live data comparing it to what the gauge is showing. the PCM takes a difference between the sensor on the intake and the one mounted to the firewall. in GMTDscan set the solenoid to 100% and you should be able to easily move the rod on the actuator at idle, 0% and it should be stiff where you cannot move it by hand. on my 95 it took me a while to realize the solenoid vacuum lines were backwards!