so how can I tell? I heard someone say that they open(or close) when you start the car up.
Obviously they won't engage if I just rev the motor in nuetral so short of getting a friend to ride under the hood while I hit vtec (hard to find voulenteers), I have no idea what I can do. Any and all help is appreciated!

 

I thought if you had it in neutral and revved it past 4800 RPM or so, you could see the IAB valve open and close.

 

Dang... you're probably right. I'm not sure but you might have to actually have some load on the motor.

 

Sorry for being off topic but ive always wondered if VTEC engages in neutral. Ive never been given a straight answer. Also i wouldnt be surprised if VTEC doesnt engage in neutral that the IAB's dont either.

 

You guys make it so hard. Secondaries are normally OPEN when the car is off. Then, from anything before 4800 RPM's the vacuum box causes them to close. So check to see the differences between off and idle.

 

i can say for sure that the secondaries will open in neutral if the motor is revved past 5k. Thats how i checked mine and sure enough they opened in neutral. i'm 99% sure vtec didn't engage, IIRC vtec won't engage unless your going a minium of 17 or 19 mph.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by TimeRacer &raquo;</TD></TR><TR><TD CLASS="quote">You guys make it so hard. Secondaries are normally OPEN when the car is off. Then, from anything before 4800 RPM's the vacuum box causes them to close. So check to see the differences between off and idle.</TD></TR></TABLE>
well then, I guess my seccondaries aren't working... . I must have the wrong solenoid, otherwise I am boggeled.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by delLudeVTEC &raquo;</TD></TR><TR><TD CLASS="quote">Sorry for being off topic but ive always wondered if VTEC engages in neutral. Ive never been given a straight answer. Also i wouldnt be surprised if VTEC doesnt engage in neutral that the IAB's dont either.</TD></TR></TABLE>
As the other guys said, Vtec doesn't engage in nuetral(stock, that is). When I had my fields controller I know for a fact that I could get vtec to engage in nuetral. I think that was because thefields used RPM, instead of oil pressure to engage Vtec.

 

the ecu determines the rpm that the VTEC will engage.
it is based on several factors that the ecu is monitoring
the stock cam changeover for the h22 is between 5000 and 5500
it is not a fixed number

the coolant temp
VSS input (wheel speed)
knock sensor
the intake air temp
and several other variables that honda calls "ecu calculated engine load" i think intake air temp falls under that also.

determine when the VTEC will engage

basically u have to be going 17+ Mph, head coolant temp must be above 153* F, and the ecu must get a from the vtec pressure switch, indicating the vtec solenoid is functioning correctly.

~boom

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ludeboom &raquo;</TD></TR><TR><TD CLASS="quote">
it is not a fixed number

the coolant temp
VSS input (wheel speed)
knock sensor
the intake air temp
and several other variables that honda calls "ecu calculated engine load" i think intake air temp falls under that also.

determine when the VTEC will engage

</TD></TR></TABLE>

your mostly right boom, except the cam cross over for vtec IS a fixed rpm, the intake air temp doesn't have anything to do with vtec working unless for somereason you IAT sensor was messed up and caused the ecu to go into limp mode, then of course vtec will not engauge.. but the IAT is not one of the requirements that the ecu checks.

the only thing that can make what rpm vtec engauges change is throttle position, if you feather the car all the way up to 6k very slowly, then mash the gas then vtec will engauge at what ever rpm you are at above 4800, the TPS sensor is what determines engine load, and is one of the things the ecu takes into account

just thought i should correct you, and boom he was talking about the secondary runners, not vtec

 

VTEC does have several 'engagement points' for the ecu to chose from. It engages sooner if you punch it, rather than having the throttle barely open.

As far as testing the secondaries, the easiest test is to watch them when a friend starts the car. The default (car off) is open. To test them with the car running, but in neutral, you have to punch it. They won't open if you 'sneak' up to the open RPM as the spring isn't enough to overcome the vacuum, punching it lowers the vacuum, allowing them to open at the desired RPM.

 

so not to be to OT but if my iat sensor is bad...which I think it is
then I may be in limp mode? But I do get a ridiculous noise and power
at a little after 5K. and does anyone know a part # for the IAT sensor?


Sorry for the trhead jack....hehe