I've already searched and found some answers, but none have been the remedy. I had recently installed a VAFC II, fuel filter, and new cap and rotor. Everything was running fine, slightly rich, but that was fixed when i retorqued the fuel filter. VTEC was fine.

1 week later I threw on a Spoon 4-2-1 Header and Carsound Cat... and thats when the trouble begins. For whatever reason, VTEC isn't engaging anymore.

I've checked the oil; level is fine and oil is clean. It isn't the MAP sensor either. I switched with a friend and still no VTEC. I checked all the wires on the VAFC II and it was fine. Coolant is also fine.

Anyhow, I'm lost on where the next step is. According to the VAFC II vtec input and output is fine. Help me out people. I miss my VTEC... Thanks in advance!

If this helps... other mods include Comptech Icebox, Fuel Pressure Regulator, and Greddy SP exhaust. Timing is stock. I thought maybe it was just quietly kicking in, but no pull at all.

 

Are you throwing any codes at all?

 

Just the Evap code (gas cap). Other than that is the 02 Sensor...

 

I was haveing the same problem as you are now. I threw on a Toda header and my vtec was engaging with ith open header. But when i put on a test pipe my vtec stoped working. I was throwing a o2 sensor cell because i wasn't runnin one of them with the test pipe. I couldnt figgure it out i tried everything and got nothing. people at first told me that the o2 sensor would not effect vtec, and i myself didnt think so eather. But then i talked to a couple guys and they said that with the o2 cell it can throw the computer into limp mode which will then not let vtec activate. So you might want to look into that. My only problem was that i wasnt running a stock computer i tried 3 different oem Ecu's and my EMS and got no where.