I have a 91 hatch with a b16a. obd1 motor and ecu. I had it running with a obd1 pr3 ecu and it hit vtec fine...then it just stopped. Tried out the ecu on my friends b16 and it didn't work. So I put in a new vtec solenoid and chipped vtec ecu, and still doesn't work. ONLY way it works is, if I wire a button to a 12v source and the solenoid.

Any ideas on why it's not working?

 

Check the continuity from where the harness plugs into the ecu to the vtec solenoid and see if the wire is still good. Ultimately you could have a bad IAT sensor (White sensor on the intake manifold), which for me, made my vtec stop kicking in on my civic (obd1 also)

 

Yea my jumper harness looks hurt, but still making contact. I'm gonna try out a different IAT sensor and see what happens.

 

Also, I have no CEL codes. Shouldn't that bring up a code?

 

do u have oil in the car? sometimes low oil wont make vtec kick in. also ive heard of the MAP, and VSS sensor wires making vtec not work, also look at the oil pressure wire and make sure thats all good

 

all wires and oil is good...bump for more help

 

Knock sennsor mabe

 

Knock sensor is eliminated, with this ecu.

 

well like you said if you put your ecu in your friends and his wouldnt engage, its your ecu. get a new one =P cause if works from a switch everything mechanical is working.

 

have you tried a vtec light yet?

oh.. check this thread too

https://honda-tech.com/zerothread?id=830163