Might be something to do with the pressure release valve, that is about the time mine failed and needed replacement??

 

It's not the injectors. 2 completely different sounds. I located it down to the turbo area. Then on my way to work tonight it idled at 1500rpm, even in closed loop. So I'm thinking now there must be a vacuum leak. Maybe in the morning, when I get home, I'll spray propane around the manifold map sensor and vacuum ports to see if any of those are leaking. Don't think the lower map should cause a high idle.

 

Curious, what effect does the propane produce? Never heard of this.

 

The engine will stumble when it ingests it. That's how you find your leaks. Because it's heavier than air, start at the lowest point you want to check and work your way up.

 

Makes sense, learn something new everyday.

 

Racing trick Quick way to find a issue in the pits.

 

Well after using the service that Spozo put up, the correct calibration is in there. So either the plug and play adapters are not making good contact or I have a lazy sensor. Don't have time to mess with it myself, so I guess I'll run it back by the dealer. Hopefully they have some TMAP's in stock to either fix it or rule out that being the issue.

 

I got my GMTU with the quick connects installed on my 2008 automatic last week. The dealer told me their tech had done a few gmtus on HHRs before so I felt it was in good hands, and so far I've been right. all week it's been great since i left the dealer No codes no drama no "learning". I see 15psi on moderate acceleration and about 22 23 psi when I floor it. I feel the power freakin awesome. I did respond to another thread here is the link https://www.chevyhhr.net/forums/show...=19891&page=57

If you read on this thread I was asked about what some call a "issue" its too long to type just check out the link and you will see it but I honestly don't know if it is a problem or not. But anyway its just something else for u to look at if you want more info. Hope this helps oh and welcome to the forum

 

This is the norm on a install.

There can be some learning but they are very small and not very noticable from what I was told. The reprogeamming takes car of most of the major issues and adapts the engine to the three bars.