the car is usdm civic si. the ecu is stock. the engine is b16a, what should i use to control the vtec with. also what happens in the ecu when vtech engages: timing changes? fuel changes? both? any help would be great.

 

Need more info. USDM civic si covers vehicles from the 80s to the present. I also need to know which ecu you are using.

 

Are you trying to get Vtec co "crack" earlier?

 

Don't change the VTEC setting.

 

its a pm6 and 1991 year.

 

i just want it to work.

 

Get the correct ECU OBD0 PR3 or PWO

 

Non vtec ecu for a vtec engine...hmmmmm. Wonder why its not working?

 

thanks thats a good idea but what if i used one of those apexi neo controllers,could i set it up so it only corrected and changed things when the vtec turned on? or do these only work on vtec ecus.

 

stop half assing **** and do it the right way

 

yea but its got a great mix of power and economy. and thanks for the flaming i love it when people do that.

 

but i like twiddling ***** and buttons.

 

Then buy one and see if it works if you like to go in circles and buy things twice. The ECU isn't set for it. Only way I have seen a non vtec ecu run vtec is if the OBD1 ecu is chipped.

 

are all pr3 ecus obd0, i have researched them and thought they used two o2 sensors. was i wrong? is there a pr3 that is obd1.

 

There is an OBD1 PR3 ECU. The obd0 pr3 and pwo use two single wire 02s where as the obd1 uses a single 4 wire 02.