Vtec still not working, i have a theory...

chiaxi2002 · Oct 20, 2010

Ok guys, after all these months my vtec is still not engaging so I had a theory.

So, "Vtec controller" if I am correct changes the vtec engaging point. So in theory, I can't rev past 4.5 because that's my vtec engaging point. So, if I were able to change it to like 8k rpm, would it be able to rev past 4.5k rpm?

sounds like a stupid question, but what the hell, what do you guys think???

kn0x47 · Oct 20, 2010

4.5k isnt the vtec engagement point

jwong512 · Oct 21, 2010

The vtec engagement point for the F23 is 2.5k and the J30 is 3.5k I believe. The reason it won't let you rev past 4.5k is because the engine probably thinks there is something wrong with the computer and won't let you rev that high in order to prevent any further damage. Check your oil level and your vtec solenoid. If there's a problem with any one of those, it won't let you rev past 4.5k. If your air filter is insanely clogged, I wouldn't be surprised if you couldn't get past that limit because not enough air flow is allowing the engine to breath enough.

chiaxi2002 · Oct 21, 2010

the only code that i was able to pull was p1457 which is emission control system leak detected. everyone i talked to said this does not effect vtec. i may be wrong though.

jwong512 · Oct 21, 2010

chiaxi2002 said:
the only code that i was able to pull was p1457 which is emission control system leak detected. everyone i talked to said this does not effect vtec. i may be wrong though.

Well, there is a chance that if the sensor thinks there is a leak, it wouldn't be able to determine how much air is really flowing out of the car and would therefore limit your rpm to 4.5k as a safety mechanism. If that's the case, check your header, flexpipe, and exhaust. Just get the crack welded up at any muffler shop.

CrosCntryAccord · Oct 21, 2010

your vtec isn't providing you with enough power that you should be wasting your time worrying about it

here's a stock dyno, you tell me where the vtec is making the difference in the linear powerband and i'll tell you how much energy you should put into fixing it