more vtec questions

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AFhondaman

New Member
Ok so i put a B16a2 in my 94 civic lx. Ran the wires for the vtec, hooked up the plugs, but i can't find the pins for the ECU anywhere. Is there anywhere i can get pins that i can put in the ECU plug without going to a junkyard or buying a new harness?
 
I would just go to a junkyard and remove 2 ecu pins. pretty easy to do with a small screwdriver and a pair of needle nose.
 
well i finaly got some pins from the junkyard and put everything together but now my VTEC won't disengage. As soon as i press on the gas a little i can hear it engage and the engine RPMs drop and come back up repeatedly until i let go of the gas. I've triple checked my wiring and it's all good. Does anyone know for sure what signals i'm suppose to be getting from which parts at which times? Such as, i'm getting a ground from the VTEC pres sw at idle and the sw contacts are closed. I unpined the pres sw wire from the ECU plug with the same results. Also i have constant power going to the VTEC solenoid so whenever i disconnect it, the VTEC shuts off. Could i have a bad ECU or would there be another culprit?
The CEL is on also with the VTEC code 21.
 
when you say your running a constant power to the solenoid are you running it straight from the battery or from the ecu?

code 21 is the vtec solenoid
 
it's wired to the ECU plug A pin 4, the ECU is putting out constant power on that pin keeping it engaged
 
You have to wire the solenoid to the correct pin on the harness which leads to the ecu. Sounds like you either wired the pins in backwards (the pressure switch stays constant), and vtec solenoid is rpm activated. OR, your pin locations are incorrect. Get the wiring diagram for the harness and for the p30 your using. Make sure you have your pins in the correct locations.
 
t3t4delsol said:
when you say your running a constant power to the solenoid are you running it straight from the battery or from the ecu?

code 21 is the vtec solenoid
Click to expand...

Thats impossible to do, because 12 volts will fry the circuit almost instantly. Keep in mind the ecu uses 0.5V, DC.
 
Correct me if i'm wrong but this is how i understand the system to work. The pres sw monitors oil pres. When the pres gets high enough (higher RPMs) it closes a ground circuit to the ECU (plug D pin 6) telling it to engage VTEC. The ECU then sends power out (plug A pin 4) to the VTEC sol engaging VTEC. I've checked wiring many times but i'll check over everything again tomorrow. I feel like that's the problem but i can't find any mistakes.
 

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The ecu looks for oil pressure (from the pressure switch) before it will engage the solenoid for operation of vtec. Simply saying, you are correct. This doesn't mean your wiring is correct. Make sure you have the correct ecu pinouts, and the correct engine harness diagram. That is the only thing I can think of your problem being.
 
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