Vtec question

I have a 02 and just noticed this morning that the vetec didn't work ,not sure if it has to really warm up or is it a problem with a sensor or something .
Any answers would be great

 

On mine VTEC won't engage until the engine has warmed up. Don't know about the '02 models but I suspect they are the same.

 

So I wonder if the engaging of the Vtec is mechanical or a sensor engage ?
Is there any expert out there have the answer ? I do know that the Vtec opens the second exhaust valve at 7000rpm
But how does it open ?

 

It's both mechanical and ECU. As I understand the operation (which is probably an oversimplification) the VTEC valves are closed until the ECU allows oil to pump up the lifters(?) so they will open. Until the ECU senses proper RPM and engine temp it prevents the lifters(?) from expanding enough to actuate the valves.

I don't know that they are exactly "Lifters" in the true sense, but there is some mechanical device there that is enabled or disabled hydraulically by the ECU that controls actuation of the VTEC valves.

I can look in the service manual tonight but I don't have it here at my office.

 

I want to say the VTEC will engage if the temp is above 130 or 135? It happened to me one time at the track last year by accident. I remember seeing the 130's on the dash. Maybe someone has a definite answer to requried temperature.

 

V-Tec will not kick in untill engine has warmed up aprox 130 - 135 degrees
this is normal

 

ya that's gotta be it .it was just a couple degrees above freezing this morning and I thought that driving for 10min it would of been warm enough .
By the way smooth running bike looking forward to doing a couple long trips on the bike

 

you are correct Vtec does not engage until engine is above 130-140 F
and it allows intake valves to open, too. you can verify this when you take off when you first crank her up and temp is below 130. I usually let mine warm up till the temp gauge starts to read.(95-100 F) while I buckle my helmet and put on my gloves.

 

If you'll turn to pg 4-22 in your hymnal (manual) you'll see under "operating conditions" that the engine temperature has to be over 65C/149F for the ECM to send the signal to the solenoid valve that allows your VTEC to engage. The ECM also looks at the side stand switch and ignition pulse generator signal before it allows the VTEC to engage.

Action

 

Same here. Switch on the bike, get my gear on and by the time I pull the bike out from behind the car and onto the driveway the operating temperature is around 100F. Not sure if it is good to hit high RPMs before operating temperature is around 150F. I actually wait till I am closer to 170F to engage the VTEC. I find that that below 180F when I engage the VTEC the kick is higher and more pronounced.

 

AS 02vfrrider said .

PLASMA

 

Just above freezing? Yaaaaoooowwww! We are expecting 99 today here in the desert!

 

I just love it when you lead the Congregation in song, Action! :thumbsup:

(Thanks for quantifying the exact conditions for VTEC arousal!)