Hey guys so i'm new here to this forum just looking for a bit of technical advice for my honda. I own a 95 accord coupe, i purchased the car with an H22A1 motor swap already in the car and since then ive been fine tuning and fixing the hatchet job that was done putting the engine in, so far i love the car and had a lot of luck getting it to run right but i still have one issue that bugs me constantly. After the car is warmed up to normal operating temp when driving through town at 40mph in 4th gear the vehicle pops as if there were a spark plug wire grounding out, now ive replaced all plugs, wire, cap and rotor so i know its not that but when my car is acting like this i also have the check engine light set and its always Code 21 VTEC Solenoid Valve malfunction. My concern with this is I have a APEX VTEC AFC running the vtec solenoid i have it set to engage at 4200rpm and it does not matter if i change the engagment to a higher or a lower rpm its still the same, could the fact that the ecm wants to see the VTEC engage when my oil pressure reaches the correct point and it doesnt until my AFC tells it to be causing my problem? If anyone has any ideas for me im very open to idea. Thanks for your help.

 

What ECU are you using? If it's trying to trigger the VTEC solenoid at a lower RPM, then it expects to see the VTEC oil pressure switch respond.

 

Is the vehicle popping when you are at ~4200 rpm?

 

Ive got the stock 95 honda prelude VTEC ecm just reset and im running a APEX VTEC AFC1 in the car right now. And no the car only pops now while driving if i dont use 85 octane in the winter and fall and 87 octane in the spring and summer. I was thinking of getting the car dynotuned again it hasnt been retuned in probably 5-6 years and ive just been trying to get all the major things fixed before i got to this problem.

 

You're using the AFC1 to control the VTEC? Then your ECU can tell that it's VTEC terminal isn't hooked up to anything so it throws code 21.

 

X2 Vtec E is much different than an H22, it sets at like 2300 i believe relieving one of your intake valves on each cylinder. It is Economy V tec for fuel mileage. Surprised it runs at all.