Gee, I thought that's what my post WAS referring to.

 

Well, I changed the by-pass valve with the/a new Dejon spring. Ok, can I get a holy crap? Dude, that made a huge difference in response to acceleration, seems to have no more bogging, and my exhaust seems much deeper....

Not to mention, when i removed the by-pass cap, the diaphragm was completely stuck open. This would explain my turbo cavitation!!! Then, took it for a ride. I think that spring was so worn out that it was leaking a great bit of boost (Even though it was staying in the system). You follow that rubber hose, and the air goes right back into the inter-cooler tubing. I was feeling like I was bogging or the engine just didn't have its take off power (normal driving). Kinda, like someone first learning how to drive a stick. But, I'm not learning. Then much the response of the accelerator has returned. Also, the 'phsssst' coming from the by-pass valve has changed in sound. Its a little deeper now????? Oh, yeah it feels like my new HHR again. Finally, I find my exhaust is fricken much louder at idle. I guess its getting its full exhaust PSI again; "I don't know, but 'sumthin' definitely changed!!! "Its hard to believe that, that much air was escaping."

Now, for the surging.....my HHR has been surging for so long, I have to be honest its like my body wants to feel the surging. Yesterday, I didn't drive for long after I replaced the spring. I will drive for a couple of days before I get excited that I am not having any surging. I will get back to you guys on that issue. I don't want to get my hopes up just yet. All, I know is this fricken spring put some spring back into my 'SS'. The spring did correct some issues I was having (bogging,misfire feeling during normal acceleration, turbo cavitation, and bad idleing); the surging is so OFF and ON, that I don't know if yesterday afternoon was on OFF day. So, I want to experiment first. If this doesn't correct the surging, I will go O2 sensor next. T-map sensores, ECM, by-pass spring and MAF sensor is NEW. Sooo, ???? Master mechanic at GM (high performance addict!!) does not want to solder the wires. He tells me the 4cyl vibrates way to much compared to V8, and that over time, the heat will cause the solder connection to become brittle with breaks.

 

"Now, for the surging....."

If you still experience any surging, just make sure all of your "air" connections are tight. Especially at the IC behind the front bumper, you may be able to stick your hand down there (in front of the radiator, drivers side) to tighten the clamp. I repositioned mine so it is easy to do now.....if I remember correcty, it takes a 11mm socket to tighten. Anytime I've experienced a surge, I tighten all of the clamps, and guess what?, no surge. I retighten every 3 or 4 weeks now, as regular maintainence, and have not had any issues as of yet...............Tom

 

thats correct, any time you have a boost leak you will have iddle serge.

 

Well guys, I am aware of this. I have done everything. My 'SS' has been in the shop for aprx. four weeks in a row. This is of course getting it back on a day and realizing that it is not fixed. Then it sits in my garage for a week right before I bring it back for a week. SUCK!!!!

Now, I have tightened everything. Many components have been changed (top t-map sensor, ECM, by-pass spring, MAF sensor). Tuesday they O2 sensor is going to be changed. Don't know what to do after that.

Literally feels as if I am passing Through little water puddles, but no puddles on the road and no sound of water hitting the bottom of the vehicle.?????

Also, still getting 20/24 psi of boost on WOT...

 

Taking my car in tomorrow for the third time to have this looked at. Wish there was a Cliff's Notes version of this thread but I'll take some time before I head in to read through it all and give the tech some notes. It's actually gotten so bad that I can feel the car shaking when it happens, and it's even stalled out completely at a red light twice (auto tranny). Ugh. Only just hit 20k miles too.

 

Well, O2 sensor was changed today. I have to say, I don't feel my 'surging' feeling or sensation as much or any at all. Now, like I said before, my 'SS' has been doing this for so long my body almost feels like it wants to do this. So, just from the ride home today, I have to say I really didn't feel it. I also thought of something!!!!! If this is surging, then wouldn't I see my boost gauge accompanying this surge by moving up and down. Well, mine was/is not when the car surges. This makes me think more on the electronic side than mechanical outside the turbo system. I guess my next step will be plugs and modular electronics connected to plugs.

My O2 sensor is now NEW: gas mileage on dash shows a mush higher number now (28mpg at 60mph this am-----after new O2, 39mpg at 60 mph), not sure that I felt any surging really, car ran with much vengeance today. "Being that this is an 'ON' and 'OFF' problem, I will give that a few days before a say NO surging."

Tech said that the O2 sensor was very black; more than it really is supposed to be at my milage (32,000+).

 

So I found this forum on google...read it and decided I HAD to post. I was having the same surging problem. Took my HHR SS in *6* times, and they couldn't figure it out. They checked turbo dump gate, air inlets, etc. Never could find it. Car never would throw a code. Needless to say, I was pissed. Brand new car under warranty and they couldn't find it. Anyway, about a week after the last time I got it back with yet another "unable to duplicate", I mine finally threw a code. It ended up being a bad fuel rail pressure sensor. When my light came on, the first thing I did was hit my onstar button and have them run a diagnostic for fear that the light would go back off. They conferenced me in with my local chevy dealer and told them what the code was, and voila! Havent had a problem since. Hopefully this will help you guys out.

 

Now, I have been having this problem also; when you say surging, is your Turbo boost gauge showing this too. Orrrrr, not so much. Mine doesn't really respond to the surge. It just feels like the car is going through MULTIPLE waster puddles, but NO water.....

 

They've had it since Tuesday, so far they kept having the problem reoccur after they thought it had been fixed, and now there's also an issue with boost leak that wasn't there before. Sucky. I'm in a base Cobalt rental, power nothing and that includes the engine. Just canceled the damage waiver today cause I'm only driving the thing to work and back and don't feel like paying $20 a day for it. Now watch a tree fall on it or something, knock on wood. I'll post up their eventual solution once I get the car back, hopefully Tuesday or Wednesday.