air intake...... If you change to a imco muff.and a k&n air intake, which combined will give more air, WILL the ecm have to be re-ajusted to a richer setting.Thinking of getting both but do not want a lean running engine. Does it re-ajust by it self? THANK"S KELLDOG

 

Yes, after a short time it will adjust on its own.

 

So that means for a short time I will be frying the engine . HMMMMMMMMM! How long is "short time" ? KELLDOG

 

I have the K&N intake mod, and the Magnaflow Cat-Back system.
I did the K&N first, then when I installed the Muffler the documentation said to pull the fuse on the ECM (#41) on th 2007, and wait a few minutes and plug it back in. Then it suggested to drive normal for a few miles, then drive on the interstate. That is what I did. I made good notes before I started, and compared results. I am getting 3MPG more in the city with both changes on the CID. My city reading averages about 24 to 25MPG. So I am very happy with the results. I use Prem Gas by the way.

 

YIKES! SOOOO!!!! You do have to tune her for the more air. But now I am getting confused!! To get information from the horses mouth I called a k&n tech and he said you don't have to worry about a thing.The computer will ajust in seconds. Now you say to unplug according to instructions. Yet on another thread way back a hhr owner who was a gm tech said your plugs will turn white from to lean of a mix. Said you had to bring it in for re programming and top performance. Could cook your valves too to boot. Fly 2 stroke large rc. planes for a hobby. All it takes with them is one lean run and your done. Don't want to make a big deal about this ""BUT" there should be ONE correct answer. KELLDOG P.S surprized this has not been talked about much before.Kelldog

 

You don't have to reprogram the PCM after you install an intake. You don't have to reprogram the PCM after you install a cat back (or muffler) exhaust. If you get a CEL after either, check to make sure all connections have been made properly and the unit was installed properly. You can try to remove fuse, but I would have it scanned to see whay the CEL came on. You will not burn up the motor or any part of it installing an intake or exhaust. The PCM will make initial adjustments after you install to protect the motor. It will take a hundred miles or so for sensors to fully adjust. But no harm will come to your motor as long as everything was installed properly.

 

I think you are making a bigger issue of it than need be! Just relax, drive your car, and it will all be fine.

I have two HHRs and have done this with both. The car is designed to adjust. I also doubt that an intake and the IMCO are going to make such a drastic change that you'll need to worry about damage.

The IMCO is as restrictive as the oem exhaust, and the K&N intake will be drawing on the same source of air as the oem set-up. I'm think overall, maybe a 6-10 HP boost at best.

BUT, your HHR will sound a little better and breath a little better.

 

Not making a big deal about it but do like to fully understand the right way of thing's. Have read many installs that have activated different warning lights and want to be prepared for this "IF it happen's." Still have 3 different answers. Most conflicting is it changes in a hundred miles or so. And then the statement from a k&n tech "it changes in seconds." It was even recommended in past forum's by a member to change the plugs,for best heat range and performance. Kelldog THANK"S

 

If you make all those changes and notice your MPG going up..
Check your plugs for proper fuel/air mixture burning.. (might be too lean)
You might indeed need an ECM reflash...

 

Hmmm.... I guess I am used to following instructions, and I assume these folks are engineers and know more about this stuff then I do.
With that said, my hhr is running fine, and have documented an increase in mpg. So, I am happy...

When I had my Magnaflow installed, the guy at the shop said...
Do you want me to pull your battery cable to reset the computer?
I said, no... don't bother and I showed him the notes I got about pulling the fuse. He said, oh that's cool. I need to make a copy of that.
So it is common knowledge in most shops to make the ECM reset and have it reprogram itself. I am sure over time, or on a long trip, it would adapt.
But, I wanted to be able to measure a difference quicker then later.

I guess you need to take some risks sometimes, or just stay with your stock configuration. This stuff is all fun for me, and like you I ask a lot of questions, and then I go off and do things hoping not to screw my hhr up.
If you look at my pictures on this site, I am pretty happy with the mods I have done so far, and no ill affects. Everyone is very helpful on this site.
We all have a common hobby so to speak, but you need to decide what advice to use, and what not to use. Up to now, I have not had any bad advice here from anyone. There are just multiple ways to getting to the same place.

Oh... I just made another post on the K&N Intake on another thread.
Here is a good example where somone made a change to the manufacturer's install instructions. Although it look good, and kept hot air from entering the air box. It was not such a good thing to do based on there design.

I hope you are enjoying your hhr as much as I am,
Keith