Quote:
Originally Posted by djohnson
I believe there are a few standalone units out there that plug into the factory harness. When inspection time comes around, swap in the factory ECU and swap the standalone back in after you get the sticker.  |
Standalones take over the entire system and the factory ECU is not in control of that. Thus the Factory ECU thinks something is wrong with the car. Piggy backs keep the factory ECU in line so it can successfully alter signals and not screw with the factory ECU = pass emissions.
Also, swapping to go to the emission station does not work. Two problems. 1) when you plug the factory ECU back up, it has to run diagnostics and gather info from the car. The Emissions station can't read the ECU while it's in diag mode and they will tell you to go drive around your car until it's finished. There in lies the second problem. 2) When you drive around your car on the factory ECU (granted it's modded enough for you to warrant needing a standalone), it won't know how to act with injectors that are 3 times the size of factory, or if you running a Blow-thru setup now, it's going to look at the MAF like it's malfunctioning. Thus creating a CEL.
Only way to beat the emissions station is to A) Use a Piggyback, B) Pay someone to let you pass C) Have a standalone and a piggyback and when you want to go to Emissions swap in the Piggyback that can still successfully control those injectors and your setup.
When I upgrade to a standalone, I'll keep my E-Ultimate for Emissions day.