Intermittant boost problem.
Senior Member
Joined: 07-05-2008
Posts: 5,464
From: Akron Ohio
I've gone through the same issues and more and I don't think it's the sensor hitting the ac compressor, given the fact it looses boost for such a long period.
When mine hit the ac compressor under torque, it would cut off power in an abrupt manner then come back on.
I'll bet you dollars to donuts that the wires spliced from the new sensors were not performed properly and have a clean connection. It takes a constant 5v connection to keep it from doing what the op described.
Now to backtrack.
I had the turbo upgrade installed and after many trips to the dealer it turned out they broke a vacume hose.
Then I noticed hard off the line it would stumble, so I added the ttr hard motor mount (it helped but did not cure it), then moved the inter cooler up 1/2" wish washers. Once again it helped but did not cure it.
Then this week started getting surging and a drop on the highway to zero boost, then back up, then back down then more surging.
I took it to my local shop (I've given up on the Santa Monica dealership) and we checked the wired on the top sensor. There were holes in the crimps and they were touching each other. We heat sealed the crimps, separated the wires and now it runs great.
One more note. With the auto, regardless of the mode you set it in, comp, tc off, or even esc off, if you come off the line hard with traction it will shut the power off, then on then off as if to protect the transmission or do some form of traction control correction.
If you come off the line spinning the tires, no drop in boost, no problems.
So I probably will add a tune that will override this.
In summary. First, check the crimping connections. I bet they've been done in a half ass manner.
IMO
JR
When mine hit the ac compressor under torque, it would cut off power in an abrupt manner then come back on.
I'll bet you dollars to donuts that the wires spliced from the new sensors were not performed properly and have a clean connection. It takes a constant 5v connection to keep it from doing what the op described.
Now to backtrack.
I had the turbo upgrade installed and after many trips to the dealer it turned out they broke a vacume hose.
Then I noticed hard off the line it would stumble, so I added the ttr hard motor mount (it helped but did not cure it), then moved the inter cooler up 1/2" wish washers. Once again it helped but did not cure it.
Then this week started getting surging and a drop on the highway to zero boost, then back up, then back down then more surging.
I took it to my local shop (I've given up on the Santa Monica dealership) and we checked the wired on the top sensor. There were holes in the crimps and they were touching each other. We heat sealed the crimps, separated the wires and now it runs great.
One more note. With the auto, regardless of the mode you set it in, comp, tc off, or even esc off, if you come off the line hard with traction it will shut the power off, then on then off as if to protect the transmission or do some form of traction control correction.
If you come off the line spinning the tires, no drop in boost, no problems.
So I probably will add a tune that will override this.
In summary. First, check the crimping connections. I bet they've been done in a half ass manner.
IMO
JR
Many people do not know there is even a special tool to remove the grimps too.
Just think about this if you ever has airbag work and they replace the crimps in the steering wheel. I wonder how many of those are not done right.
Thread Starter
Member
Joined: 12-20-2008
Posts: 41
From: NM
It doesn't happen under hard acceleration. It happens when I ease into it.
It doesn't stumble or miss. It just never creates any boost at all. It's like there is no turbo.
When it happens, I can back off the pedal and nail it to get it to boost.
It doesn't stumble or miss. It just never creates any boost at all. It's like there is no turbo.
When it happens, I can back off the pedal and nail it to get it to boost.
Senior Member
Joined: 07-05-2008
Posts: 5,464
From: Akron Ohio
Not hitting the AC then.
Senior Member
Joined: 11-18-2008
Posts: 744
From: Oak Harbor, Washington
Senior Member
Joined: 11-27-2007
Posts: 1,115
From: Austin, Texas
My bet is that it is very likely the Wastegate Actuator (this is a solenoid with three ports on it, located near the turbocharger). A bad actuator can cause low boost and also uncontrolled full boost. Known problem if you look in the "recall" postings. I just replaced mine for an "overboost" condition, but the more common symptom is under or no boost due to a cracked fitting.
https://www.chevyhhr.net/forums/show...t=23231&page=2 go to Pip4520
https://www.chevyhhr.net/forums/show...t=23231&page=2 go to Pip4520
Senior Member
Joined: 11-15-2008
Posts: 1,599
From: Newburgh, NY
I happen to be one of the success stories. Not sure if it's luck or diligence. I was skeptical as the next guy, but I couldn't let life go by knowing that I have a legendary GM "SS" vehicle that was engineered by GMPD and was not all that it could be.
Before considering the upgrade, I studied the specifications and focused upon the installion proceedures. I interviewed 3 dealerships before I felt confident that I found one with the proper tooling and experience to do this upgrade (utilizing the factory specified Duraseal crimp connectors with the proper J-38125-8, GM P/N 12085115 die/tool & torch). I happened to be lucky enough to have a tech that was not egotistical, but shared with me what I expected and what they were going to do (i.e. we discussed the A/C piping clearance). I also gave them the advisory that was posted on GM Tech Link. I checked the installation after the service was performed. I had to check the clearance of the A/C piping after I returned to my home shop so I could put it onto a floor jack.
There are others in this group that are just as diligent, but remember that when most of the kits were installed, many dealerships didn't even know what HHR SS' were. They may have been victims not of shoddy workmanship, but unknowingly improper installation proceedure. Experience was slim picking. My dealership happened to have done more than a few Stg kits on Cobalts as well as 2 on HHRs. I would think that things have gotten better in general today.
Needless to say, I'll be going on 1.5 years and 18k mi on the GM Turbo Upgrade install without a stitch of trouble, but have been having the time of my life driving the thing...
Not sorry in the least that I went for it...
Senior Member
Joined: 05-13-2008
Posts: 2,075
From: Knoxville, TN
The reason being is a voltage drop, when the signal has to navigate the conector blades, it is spread out over a larger surface area causing the voltage to drop, thus not sending a strong enough signal to the t-map. Check the load on either side of the connector, don't know if this has to be done in gear or not. I would imangine chocking the wheels and standing on the brake while giving it some gas should give you a good signal accross those wires to check for voltage issues, if this then remove the blade connectors and solder in 4 jumpers.
I wasn't having problems with the AC hitting, although it was really close. Now that I have HANN's pipes on I had to reverse the bottom T-map, and move the radiator foward about 1.5 inches. I will never worry about the bottom T-map again as I can easilly get my fingers completely around the sensor. The pipe was a pain, but if you could see how tight of a fit that lower T-map is you might consider new IC pipes, just for piece of mind.
I wasn't having problems with the AC hitting, although it was really close. Now that I have HANN's pipes on I had to reverse the bottom T-map, and move the radiator foward about 1.5 inches. I will never worry about the bottom T-map again as I can easilly get my fingers completely around the sensor. The pipe was a pain, but if you could see how tight of a fit that lower T-map is you might consider new IC pipes, just for piece of mind.
New Member
Joined: 05-19-2009
Posts: 23
From: Detroit
I had a similar problem. It turned out to be a small crack in the intercooler that would only leak under certain temperature/humidity conditions etc. If you haven't figured it out yet, that's something you should check.
