Installed air bypass valve on AEM CAI last night but forgot to reconnect map sensor so CEL light up when I started engine. Reconnected map sensor and followed instructions in Library to reset ECU. CEL went off and took it for a test drive. Drove the car last night and today and car feels so much stronger. Low rpm hesitation gone and seems to pull stronger throughout powerband. This is the first time I've reset my ECU and I have about 20K on my car. I doubt air bypass valve had something to do with car feeling stronger since it specifically says in the instructions "in some circumstances, cause a very minimal reduction in the increase of hp given by the CAI system". So question is does resetting ECU make engine run better? I know some people reset ECU after doing mods so was wondering if there are valid reasons for doing this.

 

I reset my ECU quite often. At times, I will just pull the ECU backup fuse and leave it out. The only downsides I've noticed to leaving the fuse out is that the headlight warning beep doesn't work, the A/C resets every time you turn off the car, and the idle fluctuates at the first few stop lights of each drive. On the other hand, the benefit is that the car runs strong all the time.

I have argued this in several threads, but I think all the "learning" that the OBD-II ECU does just reduces performance by retarding timing and richening the Air / Fuel ratio.

 

interesting...wish there were some kind of quantifiable comparison

 

So how does one reset the ECU , I have only 5500 miles and am stock but its worth a try !

 

It's the 3rd slot on the right bank of fuses under the dash. Pull it out for about 30 seconds. If you have an American car, it's the second fuse from the top. The first slot is empty unless you have a car with DRLs.

 

Thanks Xviper , I will try it !

 

Sounds like it's time for a dyno field trip.

 

I recently did a few dyno runs to tune my V-AFC. I reset my ECU before my last run. The last 2 plots were identical. I took it to mean that resetting the ECU definitely won't loose power, but if the ECU has been retarding timing for some reason (bad gas, heat, detonation, etc.), it will probably restore power.

 

Good info thanks gernby.

 

I may give it a try too.