Standalone in Parallel with stock ECU

[tmontague]

Is anyone on this forum running a stand alone ecu in parallel with the stock ecu? Meaning hvac, dash and everything else is still working. Does the OBD II still work in terms of showing readiness signal (for passing e test) and do any CEL's pop up?

How do you get the stand alone to over run the stock ECU to run things like timing and fuel if both ecu's are connected? If you disconnect the stock ECU from the timing and fuel components does that throw CEL's?

I'm trying to get a better idea if this is possible in a etest province

[xnamerxx]

My ECU is currently wired up this way.

OBD functionality remains, but you will get CEL's just how it works. You can't pass emissions doing this.

Aftermarket ECU runs fuel/spark/cam
Stock Ecu runs throttle body and interior.

[tmontague]

I see, thanks for letting me know.

Did you disconnect the stock ecu from everything that the standalone (aftermarket) ecu is connected to? I'm assuming this is the only way to no longer have the stock ecu change it all back to stock map levels

[xnamerxx]

The stock ecu is no longer connected to the injectors/spark/knock sensor.

[fnkngrv]

My EMS is running all performance bits other than vvti. It was found at least suggested by some heavy hitters in the mod scene that there would be no benefit to moving vvti away from the stock ECU as it it very efficient and stable so for the most part is just throwing away money.

As for the OBDII it will light up like a Christmas tree if you plug in a diagnostic tool. There is no real way around it unless you were to essentially spoof the signals from another device. I spoke with AEM and they stated that they don't have a proven wiring setup that allows for the EMS to spoof the signaling to the port. The only thing that I have been able to do is turn off the CEL itself.

Sent from m-o-b-i-l-e

[tmontague]

I guess the only option for me here in Ontario is buying a car that has an ecu reflash support mod like a wrx where you can tell the ecu what codes you don't want it to show. This way the tester for the e test won't see any of these codes pop up. I've been reading the wrx forums and there's been no issue passing e tests doing that here in Ontario.

The other option is buying a car 20 years or older and then you'd be free to run a full standalone since cars that old are exempt from the etest. BMW e30 anyone? ;)

[xnamerxx]

My EMS is running all performance bits other than vvti. It was found at least suggested by some heavy hitters in the mod scene that there would be no benefit to moving vvti away from the stock ECU as it it very efficient and stable so for the most part is just throwing away money.

As for the OBDII it will light up like a Christmas tree if you plug in a diagnostic tool. There is no real way around it unless you were to essentially spoof the signals from another device. I spoke with AEM and they stated that they don't have a proven wiring setup that allows for the EMS to spoof the signaling to the port. The only thing that I have been able to do is turn off the CEL itself.

Sent from m-o-b-i-l-e

I can switch my VVT from stock to AEM, I picked up something like 5 tq using the AEM rather than stock, just another thing to tune. It wasn't a substantial gain but since my ECU can account for it might as well.

If I was running bigger cams I wouldn't have the stock ecu control VVT since it wants to advance the cam to 40* from 2-4k and some of the bigger cams will lose hp advancing that much.

[fnkngrv]

Which AEM are you using again? 5tq that you see just kind of strengthens my point for my build to just leave it be. Granted I have a more powerful setup and if I upgrade my Web Cams again to be even more aggressive it could be more beneficial by only time will tell.

Sent from m-o-b-i-l-e

[xnamerxx]

I have a series 2.

Gain wise while the numbers are fairly low it's a pretty big percentage gain at that point in the range.