I do not get Vtec when my cars heater/blower is on but once i switch it off the car comes on Vtec and runs fine any ideas why

Thanks

Doug

 

Coolant temp too low?

Is the coolant gauge indicating lower than nominal temps?

Are you using a lower-temp thermostat, fan switch, or any sort of Redline water wetter-like product?

 

what i can do is switch the heater fan on and run down the road with normal water temp and Vtec won't come on but once i switch the fan off Vtec hits i am not using any different water or fan everything is stock when i hook my datalogger up everything looks normal i even re grounded the motor to the heater.

 

This does not sound like a problem with the Hondata, but a problem with your wiring in the car.