Hotrodbob

I have the stage 1 kit on my car and just had a waste gate failure per the dealer. Now the car is back and I'm not sure, but should I be able to get full boost in first gear(5spd)? Right now, I can only get 5psi in first. That said, until the engine reaches full temp now, I can only get 5 psi in any gear. Are these two boost issues normal?

XtremeSS

5psi in first is normal. Not sure about psi in other gears before car is warmed up. I never try to boost before car reaches 180 degrees cuz i hear it's not safe.

Hotrodbob

Ok, thanks..The other day it would not go over 5PSI for 50 miles..I'm sure it was warmed up, then all of a sudden the boost was back

firemangeorge

Actually with the GMTU you should get more than 5 psi in 1st. Just not full boost like 2,3,4,5. I have noticed mine hit the 8- 10 range, but then I never run 1st gear all the way out.
Also your car should be warmed up to operating temp within a short time/distance. Sounds like you may have a thermostat problem. The ecm may reduce boost with a low temp reading. Check your temp reading when this occurs.

Sidecardog1

I agree, if you haven't reached full temp within 5 miles of driving you have a thermostat or temp sensor issue or something else in that circuit. My 2010 with the GMTU, 5spd, LSD is warmed up within 5 miles and I never get on it until I see the thermostat open by watching the water temp reading on the RPD. Push the RPD knob in once to set the right side selection and then rotate the knob until the water temp reading display appears. Then push the knob once more to return the display back to normal. Watch when the temp rises up, then passes your normal operating temp. When the temp starts to fall is when the thermostat opens. Once that happens, you should be good to go. My normal operating temp is 183F unless it is a really hot day. On a regular day, the temp will rise to 187-190 and then drop back to the normal. If you drive in a non-pedal to the floor manner. Let it warm up first. If it is taking you 50 miles to warm up, something is wrong.

Hotrodbob

Full temp reached.. Temp is not the culprit, but maybe the sensor that sends the temp reading to the ECM is. Normal temp on mine has been about 192 most days. Never drops below that after a few minutes of running. I usually idle it for a few minutes before I start driving and after I come to a stop before I shut it down.

I have had 2 sensors changed and now the Turbo. Still the same problem. Turbo was warranty, sensors were not. Never had 5 psi boost limit in 1st gear that I noticed before.

XtremeSS

I have seen higher than 5 in first but it is just a spike and will settle to ~5psi. If you only see 5psi in all gears then I would assume you have CEL?

Hotrodbob

What's a CEL?

Motorbreath

Check Engine Light...or also known as a MIL - Malfunction Indication Lamp. You're definitely in limp mode. You either have a pending code or if the check engine light is on you have a hard code.

Hotrodbob

The CEL does not always come on when this happens. That has been an issue with the diagnosis. I called ON-STAR during one episode and they could not capture a code even as it was happening. They did state that there is a TSB on the turbo rod to the pressure relief or pop off valve that corrects an issue like this, but the dealer dismissed that. Not sure if the new Turbo came with the updated rod. This said I just saw a thread that says boost is reduced in 1st and 2nd gear by the GMTU ( https://www.chevyhhr.net/forums/show...1&goto=newpost ). I just never noticed this before in my vehicles operation.