I just got a new exhast put on with a flow-thru cat...and ever since its been on the check engine light has been on...i know its probably has somethin to do with the O2 sensor...but i was just woundering if this would effect my engines performance at all

i have a AEM intake and full exhuast and i can barely hear vtec kick in at 4400...but when its time for the secondaries in the manifold to work i can hear nothing....is it possible that vtec is workin and the secondaries are not??

any information would greatly be appreciated

 

Although I don't have the answer.. I do have some helpful information. If you ever unplug your VTEC Solenoid and forget to plug it in.. I believe the first stage of VTEC will kick in, but the second one won't. I can't really prove it because I didn't have an exhaust on when I had this happen to me. But I know for a fact that when it was time for the Secondaries to open up at 5000rpm or so, I received a Check Engine light.. Hope this helps a little... Later..

 

thanks for the info but i dont think that is the problem

im just woundering if my O2 sensor is playing a role in this....or maybe my hearing is just bad

 

man, i hate this misconception....all noobs think that there are two stages of vtec or something...ok clearing it up
your vtec cam engages at 4450 RPMs....and then ur secondaries open at 5750....it could be ur exhaust is drowning out the secondaries (cuz u usually hear the intake on the secondaries)...doesn't mean they aren't opening up tho...check the vacuum hose by the thing that opens up the butterflies to make sure it's properly plugged

 

1.There is no two stages of vtec.
2. VTEC crossover is at 4400-4500 and IAB opens at 5800-5900.

thats it.. plain and simple...

 

Ok this leads me to ask this question.

what does the VAFC control then?....the x-over? or the IAB?

if its the x-over, then I figure a 5200 x-over on a GSR is way too high?

 

Well, yeah... the two stages are the IM stages... not vtec... but power drops off until the 2nd stage butterflies open. I don't see why everyone is soo miffed about it... I mean we still use terms like HEADERS, PORT and POLISH which are not correct anyways....

X2

 

i know there arent 2 stages of vtec, thats why i said i can hear the initial crossover at 4400 but i cant hear the secondaries kick in (people are callin it so many names i dont know what to call it)

I was just woundering if it was possible for vtec to engage and the IAB not to (for all i know its just my ears )

Just cuz it says im new doesnt mean i havent been reading and searching other peoples posts for a while


[Modified by MilanoGeeSR, 6:01 PM 7/10/2002]

 

a vafc controls fuel injector duty cycle by modifying the signal to the ecu..

if your vafc has the vtec functino you can change the signal to the ecu for the vtec crossover.

 

You can disconnect the iab and have it not open. Some say you want to do this on a turbo car, but it's not necessary as you want the most amoutn of air as fast as possible.. there's a sensor (have to look in my helms manual) and i think a vacume line that goes to the IAB that you can disconnect. You can also turn off or move the vtec crossover up or down depending on your setup (either wth a chip'd ecu or vtec controller).

 

well there arent two stages of vtec there is only one in which it kicks in at 4400 rpm's but the o2sensor should ony through your check engine light but thats it but it is possible for the second stage not to engage that would mean that there was a vacum leak some where preventing it from opening the second stage but there is a little thing next to the intake manifold it looks like a ufo with a hose attached to it take that off and see if that is sucking air but if its not that take it to acura man....

 

I know there is a plug by the trans,if you unplug it the miles will stop rolling your speedo won't work and your secondaries won't open.And you will get a check engine light.


[Modified by maggsgsr, 7:13 PM 7/10/2002]

 

Probably the most common problem is the pressure switch in the side of your head. I elimated the sensor on my p28 in my LSVTEC to have Vtec always engaged. I found out that was the problem with mine don't know if it will help you. Vtec works on oil pressure so check your pressure.

 

isn't it true that if the CEL is on vtec will not engage??? I could be wrong, tho.

 

that is true

 

What if it came one but went away? Tech at Honda said that the code is retained till it is cleared.

 

NOT TRUE at all, please know what you're talking about before you post. Only certain CEL's will prevent vtec from engaging, not all of them.