anyone know for sure if there is a polarity issue between them? I now have an obd1 p72 running my 2001 prelude with a hondata. I have heard there is a polarity difference between them.

is this true?

 

ttt

 

I don't know what you mean....the only thing I can think of is the p72 will open them much later than the H22a..that's about all I know...

 

the OBD1 is a switch to ground circuit and the OBD2 is a loas to ground circuit

 

so does that mean one will open when the other will close the solenoid? do the wires have to be switched?

 

Well you can just open your hood and watch the diaphragm. When you start the car it should go under vacuum and close them...then rev to 5800 or something and they should open, see my post about IAB control on a p72 on an h22a...if I were you I would disconnect the plug and run them open all the time.