About 6 months ago I read an article where somebody made a VTEC timer with there shift light. OK.
I have a 1999 accord. I am an EE. I have designed a VTEC over ride. It crashes the computer. WHY? I isolated the ECU from the new activator with a diode. I also isolated the new activator. It reads the coil pack pulses and simply applies +V to the VTEC solenoid when the RPM rate reaches the programmed point. It then removes +V when the RPM rate falls below the programmed point. The ECU is still active. In other words if I remove power from the override the ECU will activate the VTEC like normal. When the check engine light comes the rev limiter point is moved to the OEM VTEC point…???
MY QUISTION:
What would cause my ECU to flag check engine, and any information that would help me with this problem is needed.

WIBER1

 

cause it sounds like the ecu is still connected to the solinoid that you are activating with +12v?

the ecu wont like this and tell you to check your engine.

it is because at the factory set VTEC point you are giving a solinoid +12v and +12v - which is not good.

you cant have your VTEC and eat it too.

pretty simple unless i missed something here.

t..




[Modified by tinkerbell, 9:40 AM 3/25/2002]

 

Thanks for the information...
With a little thought i found the problem..
I did seperate the +12 volts with a diode voltage. With the cathode side facing the silinoide voltage cannot pass to the ECU, but...
When i thought about my problem i relised that my problem was timing...
I activate the VTEC before the factory rev point, but i did not deactivate it in time.

This set the ECU to have a bad VTEC unit and disabled the car to that rev point...
You are right the ECU cannot handle a 12V input on the silinoid output line...
thanks...
I put a switch on full thortle. When the peddle is lifted the override is reset, therfore the bug is fixed...

Teh vtec is a lot smother change.

This activator will also activate a NOS selinoide SOON....
thanks WIBER1