A friend bought an ecu off ebay. supposed to be a "jun p72". his vtec wouldnt engage with the ecu on his lsvtec but it works fine with a chipped p28 that a friend of ours let us borrow. I took the cover off the ecu to investigate... how do i tell what kind of ecu this is.. I am doubting that it is a p72 since the barcodes are no longer on the side.

 

If it's a P72, it'll have a smaller (upside) board in the upper right corner of the ECU, when looking at it with the chips right-side up and the ECU plugs on the left side. If you have a camera, take a picture of the board, and post up the ECU bar code numbers if it's on there.

Also, I've never heard of an OG "JUN" program working in a P72.... only in the P30/P28/P61 ECUs only, but that's neither here nor there.

 

it can be anything.
open it up and see if it has a knock sensor board, if it does it can be a p72/p30/pr3/.
look for ic14 silkscreened on the board, if theres something there its a vtec ecu. if nothing is there, u got yourself a non vtec ecu.

 

def doesnt have that secondary board in the right corner. I am pretty sure this is a nonvtec ecu because the ecu ran fine... but no vtec engaged. probably a dx ecu