I have a SOS Stage 1 on my '05 and VTEC is supposed to engage at ~4400 RPMs or so, but it's engaging at the factory setting. Aside from a bad FVM unit (the supplied pre-programmed "piggyback"), what could play a role in the VTEC not engaging at ~4.4k but doing so at ~6k?

SOS sent out a replacement FVM, so I'm hoping that does the trick but want to do my due diligence to ensure everything is properly installed. For what it's worth, prior to the SC, I was running an AFC NEO with a Boomslang harness and I had no issues with lowering the VTEC and the car responding accordingly.

Is there anything mechanical that could be the cause? What are some factors that could be playing a role?

 

oil pressure?

 

Would that impact VTEC not engaging at the lowered point instead of not at all?

 

yes it would

 

If it's not a bad FVM, I may not have enough oil pressure at the ~4400 range, but enough at 6k where it is engaging?

Does oil pressure really vary that much above 2k or so?

 

I don't think so Jhonny. My guess is its the fvm. Sounds like you have another one coming anyway so try this out, if you still have a problem then we can put our heads together.

 

You should have plenty of oil pressure at 4400 rpms to engave vtec. Although its definetly possible that you don't.

 

Does the FVM box you have now, light up once installed and turned on??
What color is the light?

Green light means flash is good and everything is working!
Red light means (no flash or not communicating)
No light means unit is not working at all and something is wrong.


Check those things out on the FVM you have now and see whats up, and then do the same once the new one arrives.

 

The fact that it is engaging constantly at the stock 6k and not 5k or wherever below that point, but above your programmed rpm, makes me think its something electrical, not oil pressure.

 

you can hook up a voltometer to it and find out exactly when its engaging. Just have a passenger hold it in the passenger seat and get on it.