i have a 99 si. when i bought the car, everything went fine. vtec engaged nicely and it was decently quick. my alt. went bad. i changed it. and now my vtec half *** engages....i can kinda hear it, but there is NO power at all. it did this a while back and still is doing it. i dont know if changing the alternator did it or not. but it makes no since to me or anyone else around here that mess with hondas......ive tried researching it but have come up with nothing. and i was just wondering if anyone else has come across this problem or may know what the hell is wrong.

 

The only connection between your alternator and vtec is that they are on the same wiring harness. I'm pretty sure they aren't connected though, vtec probably gets its signals from the ECU and sensors.
That being said is your check engine light on?
I would get a voltmeter and use the haynes or factory manual to start troubleshooting your vtec system. Factory manual has a good guide for troubleshooting.

 

no.it should not be alternator. but did u connect all the wires properly to the alternator and positive battery terminal? any CEL. all the fuses good? car idel and runs normal except vtec engagement problem

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Gamefreak0109 &raquo;</TD></TR><TR><TD CLASS="quote"> i have a 99 si. when i bought the car, everything went fine. vtec engaged nicely and it was decently quick. my alt. went bad. i changed it. and now my vtec half *** engages....i can kinda hear it, but there is NO power at all. it did this a while back and still is doing it. i dont know if changing the alternator did it or not. but it makes no since to me or anyone else around here that mess with hondas......ive tried researching it but have come up with nothing. and i was just wondering if anyone else has come across this problem or may know what the hell is wrong. </TD></TR></TABLE>

Solenoid clogged? Oil pressure good? Any CELs?

Search around. The question "Whats wrong with my VTEC??????" is covered a BAZZILLION times a day bro

Also, im sure you're going to get the "If you hear it then obviously it's working. You're not supposed to be thrown back in the seat when VTEC cracks blah blah blah..." Could it possibly be you're just accustomed to driving it now so it doesn't seem as fast?

There are a lot of variables to your question. Just search around, check your fluids and solenoid, and if everything is mechanically sound, call it a day

 

those are very important ive seen lots of guys vtec stop working because the screen was clogged, or quite possible your oil is too low. there are only a few things that can go wrong with it if it was already working. if you know someone else with a solenoid borrow theres and swap it with yours, just do the process of elimination

 

i do have a cel, but its for the 2nd O2 sensor missing. its been on since i got the car, and i check it regularly just to make sure nothing else comes on... I have searched alot, but none of the results ive found have anything like this. I have good oil pressure, at least the oil pressure guage says i do. i have cleaned out the screen. but im gonna borrow my friends off his b16 and see if that helps any. and no its not becuase ive been driving it and got use to it. becuase it was working fine the morning i drive, the alt went bad, i changed it that afternoon and when i drove it it was 'messed up'

 

does it bog out between 1k and 2k??? and then start moving steady? if so it might be the throttle body. because on my brothers gsr swap it kept stuttering from 1k-2k and 1st vtec wouldnt even engage but secondary would so we changed everything from sensors to wires, then we finally changed the throttle body and the throttle body was the problem.. not sure why but all i know is that the car runs fine now and both vtecs engage correctly to its full potential.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Sp33ding &raquo;</TD></TR><TR><TD CLASS="quote">does it bog out between 1k and 2k??? and then start moving steady? if so it might be the throttle body. because on my brothers gsr swap it kept stuttering from 1k-2k and 1st vtec wouldnt even engage but secondary would so we changed everything from sensors to wires, then we finally changed the throttle body and the throttle body was the problem.. not sure why but all i know is that the car runs fine now and both vtecs engage correctly to its full potential.</TD></TR></TABLE>

you know....sometimes in first it does kinda bog a little......i may just have to try that.

 

does it bogg under load or just 1st?

 

just when i start off in first

 

if its only in your first gear then 50% chance its your throttle body... im really sure of this because it took us months to figure out what the problem was, and i guess the tb had a big part to do with it because maybe the old one had open/closing problems which made the car stutter between 1k and 2k and thats where it fooled us by thinking it had something to do with fuel. but yeah do try it i am almost 100% sure its the tb....

 

car is slow as ***** tho (when we ran that night)....try the TB aaron....maybe it'll work...borrow someone's

 

Im having a hard time believing that the tb has anything to do with the vtec not engaging.

I do know that under certain circumstances vtec will not engage, circumstances such as low oil, under 20mph and certain CEL's the vtec will not engage. I would fix the o2 sensor first and reset the ecu and try it and see how that works.

I do know that if your throttle isnt over 50% or something like that vtec wont engage to help save on gas mileage.
Thats just some of different types of situations in which it will not engage.

 

ive had this problem it was the vtec solenoid

 

well ill borrow my friends TB and vtec syl. one day when one of them is over...hopefully it will work

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mister_ej2 &raquo;</TD></TR><TR><TD CLASS="quote">car is slow as ***** tho (when we ran that night)....try the TB aaron....maybe it'll work...borrow someone's</TD></TR></TABLE>


ha, yea, i know it is, which is why im wanting to fix the problems, it was NO WHERE like that before. surprised you found my thread....i got the car back up and running, i may be bringing it out to harbison sometime soon

 

There is no such thing as VTEC half-*** engaging. It's binary. It either engages, or it doesn't.

I'm sure your problem has absolutely nothing to do with VTEC. You're just assuming that VTEC has everything to do with a Honda's performance, but actually, a Honda motor is just like any other motor. Fix the CEL and do the regular maintenance.

 

dude stfu......its half *** engaging......i know the difference of how it engaged before and how it does now and it is no where the same. i know vtec either works or doesnt, but seriously, the motor doesnt perform nearly like it should during the vtec range of the rpms......i know vtec isnt EVERYTHING WITH A HONDAS PERFORMANCE. dont talk to me like im a new ricer ok? i came across a problem that i cant seem to figure out and im asking for help, not smart *** remarks

 

AYO IM TELLING U JUST TRY THE TB OKAY.... I CANT STRESS THIS ENOUGH AND IF IT ISNT THE TB THEN MY FAUGHT I GUESS IT WAS A PROBLEM FOR ME. BUT IM SURE IT IS....CANT REALLY EXPLAIN WHY AS I TRIED ON THE LAST REPLY BUT RICER OR NOT THE TB DOES PLAY A BIG PART TO BELIEVE IT....

 

OP: you said you have a secondary o2 sensor CEL?? try replacing that and also check to see if your getting proper flow through your exhaust. same **** happened to me(minus the alternator issue) and the problem was that my CAT was clogged and the exhaust was BARELY making it to the end of the exhaust. replaced the sensor and CAT and presto, pulled like a champ again. something to look into

 

i have a similar problem, but nothing to do with the alt. i swapped in a JDM b16a into my 2000 si, but kept everything from the a2, all sensors, etc. except the vtec solenoid. i used the one from the jdm motor, and vtec is way quieter now. i hear a change, and the power isn't too bad, but it is way quieter. i am going to swap my a2 solenoid on this weekend and see if that makes a difference.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Sp33ding &raquo;</TD></TR><TR><TD CLASS="quote">AYO IM TELLING U JUST TRY THE TB OKAY.... I CANT STRESS THIS ENOUGH AND IF IT ISNT THE TB THEN MY FAUGHT I GUESS IT WAS A PROBLEM FOR ME. BUT IM SURE IT IS....CANT REALLY EXPLAIN WHY AS I TRIED ON THE LAST REPLY BUT RICER OR NOT THE TB DOES PLAY A BIG PART TO BELIEVE IT....</TD></TR></TABLE>

i am, my friend has a spare one he is going to let me try whenever i can get up with him, so ill let ya know how that goes.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by packman5280 &raquo;</TD></TR><TR><TD CLASS="quote">i have a similar problem, but nothing to do with the alt. i swapped in a JDM b16a into my 2000 si, but kept everything from the a2, all sensors, etc. except the vtec solenoid. i used the one from the jdm motor, and vtec is way quieter now. i hear a change, and the power isn't too bad, but it is way quieter. i am going to swap my a2 solenoid on this weekend and see if that makes a difference.</TD></TR></TABLE>

personally i dont think the solenoids make that big of a difference i think it all depends on the cams....the only difference between solenoids is that the USDM ones are smaller than the JDM ones yet ive heard USDM B16's with the USDM solenoid... pop Vtec louder than JDM b18c's

i might be wrong but this is the conclusion i have come to...

 

yeah man let me know the updates...im very interested in this one...