I'm entertaining the idea of a mild rebuild on my 3100 in my Grand Prix. Nothing too drastic, maybe a mild port job, intake mani swap, and I was playing with the idea of the Milzy stage 1 cam. My only issue is with finding a tuner that won't screw up the PCM to the point that I won't pass a plugin test. I know there'* people on here that have used HPT before; has anyone ever had to pass an obdII emissions test after tuning their car? If it'* going to be an issue I may just stick with stock parts.


For the same emissions reason I can't do any swaps, so the l67 swap is out. Just sayin'.

i dont have it yet but ive been researching for the same reasons. i was told by billboost i think you can make the computer say anything you want and stop the emissions programs and set the readiness indicators to still say ready.

so as long as you are putting in something obd2 in the car i think you could probably change the engine too

I would have to look into that and see how it works. I was told that the e-test computers pulled the VIN on the PCM and would fail the car if it didn't match the VIN on the car. Although if you can change the VIN on the PCM with a tuner...

that would be good if you could with hpt, it has to be able to be done some how, what if your computer goes bad and you have to replace it

Actually, I've passed Connecticut emissions several times in the past, and I've never been able to read the VIN out of my computer.

I'm not sure if you can change the live sensor data, but you can stop emissions codes from ever setting.

I've passed emissions with my tune. I've also got a lot of tunes under my belt and they also pas emissions.

in ny they check the system monitor status, along with the check engine codes, have you guys had to deal with that?

A option in the tune is to not report. So the PCM never even looks at that area, no code, no problem.

Interesting.

It'* good to know that I can tune and still pass. I'm still in the research stage as to what I wanna do (I wanna just do a stock+ rebuild but members on another forum are trying to talk me into a 3500 swap >.< ) so I will probably be back with more questions.

Yes, you can easily pass emissions after tuning and modifying. HPT or DHP (if DHP supprots your car) will both work well .