ok heres my question. i just did the h23a to jdm h22a swap. i have never had a vtec motor or road in a car with vtec in it. i have heard u can hear the vtec kick in. i hear nothing on mine. the motor defiantly feels stronger that my other one. they both have the same exact bolt ons: aem cai, header , apexi n1 exhaust..... would the motor even run correctly if the vtec wasnt working? i swappede out motor and ecu- my car was already prewired for the vtec. i jsut dont understand because all i read is that it makes a distinct sound. any ideas??

 

On my H22A4 I can definately hear my V-TEC engage. The motor is twice as loud at about 5300 rpms. Your V-TEC might not be working if you cant hear it.

 

If its going all the way to the 7400 rpm cutoff then its working fine. I an tell when the hi-cams engage on my car but its not like "Holy ****, Vtak just kicked in yo!" DOnt forget that there is also a dual-stage intake manifold that actually makes the engine louder at about 4600-4800 rpms when the secondary intkae runners open. I notice that more than "vtec"
Euro-r intake ftw btw.

 

the engine is suppose to red line at 8200 i think. are u saying that 7400 is the rpm cutoff. ive never read that but i dont know a whole lot about this engine...and i have another problem- my tach has not worked since the swap. so i dont have a clue what rpms i am running. the motor runs great though. sounds good too. ive got it up to bout 50 mph in 2nd and about 75 in 3rd so thats gotta be high rpms. dunno exactly how high though.

 

my jdm h22 redlines at 8200 and you MOST DEFFENTLY HEAR/FEEL VTEC :]

 

Did you use the catback from your h23? If so what modifications did you have to do to get it fitted properly?

 

hmm nothing other than i had to get a new header..... and i had a dc sports on my h23a- i just got a polished one off ebay for 20 bucks lol....i thought it would be a p.o.s. but it actually fit perfect and seems to work fine. but time will tell....i plan to upgrade to a better one when i can afford it.

 

CEL's? p13 ecu? pics of engine bay? vid.

 

You should be able to feel and hear VTEC.

What ECU are you using?

VTEC needs these things to operate:

- ECU sees coolant temp sensor at operating temp.
- ECU sees oil press.
- ECU sees above 12mph (VSS must work)
- VTEC wiring/software/hardware all working
- A VTEC ECU (duh).
- ECU read TPS above certain %

Someone chime in if I missed anything.

 

im using a p13 ecu- my wiring harness- my car was prewired for vtec- it had the plugs under the hood on passenger side- everything i read sd that meant i could just plug it in-i do have a cel. but i just read yesterday how to ck that- by using a jumper on the 2 prong plug under dash- im gunna try to do that tonite or tom. a cpl other "weird" things when i was testing driving the car a cpl days ago, it felt like all power cut out at high rmp- i dunno how high cuz my tach not working but i know it was up there. then a lil while later i could feel it pull a lil harder when i was accelerating and not changing the position of the gas petal- i was trying to see if i could hear/feel it. and one time it actually felt diff. could be a loosen conn?? i dunno i am gunna ck all wiring again this weekend...

 

low on oil perhaps? you should be able to hear it. if not then something is wrong.

btw, the motor will rev all the way to redline without vtec working properly.

 

ok this is prob a dumb question. i assume driving the car and the vtec not working is ok? it wont hurt anything? and also. if my tach is not working.. the ecu still knows when to kick in the vtec right? i mean the tach not working wouldnt have anything to do with the ecu actually knowing what rpm ur car is at ? or am i wrong?

 

Driving the car without VTEC working is fine. Don't worry about it. It will just be slow and boring.

The ECU may or may not get it's RPM signal. It depends on where the signal is broken. The ECU does need an RPM signal to engage VTEC.

 

honestly.. a CEL isnt telling you to change your oil.. Its showing up for a reason, and usually a fairly serious one. Vtec doesnt work and CEL is on... HMM.. check the code? Nope, Ill just post about it on Honda-tech...

Check the code first, otherwise our help is almost null and void..

 

Ok, is your ecu even a P13? If your using the P14 (stock si ecu) then u wont have vtec. judging by the rpm/speed you listed and the fact that you dont have a tack makes me think that your not going past about 6500. What transmission do you have? And if you have a CEL then u need to check that first and before anything else. THere is a 2P harness that is located behind and under the radio. Also H22a's dont hit fuel cut at 8200 rpms with the stock ecu. It might read that on your stock tach but its wrong.

Let us know what ECU you are using and what the CEL says. BTW, you could search and find all this. Just about every issue has come up in the many years the h22/prelude has been around and most of them are documented somewhere around HT.

 

Ok I finally got a free minute to ck the cel... 2 longs and 2 shorts.. Which means 2 right? And I can't find it on the list... Does that mean my ecu is no good... Its a p13 I ordered from tigerjapanese.... Has anyone else had this code b4??

 

I meant means 22....

 

Code 22 is vtec . Sounds like you got a number of problems. I bet you hooked tach up to VTEC in the engine bay and thats why neither work and you think its prewired. Prewired doesnt mean it has plugs to just plug in. It just means the wiring runs to the engine harness connector by the fuse box.

Wire color for vtec solenoid: Yellow/green
Wire color for vtec oil pressure: light blue Black=ground on this connector

Your obvious two problems are VTEC solenoid and Tach.

reference for why VTEC doesnt work thread:
https://honda-tech.com/forums/honda-prelude-4/official-%22why-vtec-doesnt-engage%22-thread-830163/

Reference the FAQ:
https://honda-tech.com/forums/showthread.php?t=830163
It will tell you how to wire VTEC in hopefully.

 

u sd i prob wired tach up tp vtec?? how would that be possible?? i used the wiring harness that was in the car already. i switch out the h22a distributor for mine and relocated the external coil. i assume the tach reads from the coil somewhere but i may be wrong on that. to hook up the vtec i used the 2 plugs on passenger side on top of wheel well. i had read issues where the "pre wired" cars had probs using these plugs but still that shouldnt affect my tach. thanks for the reference post i will read it as soon as i get back to a pc and can load a page that large. looks like im gunna have to take it to a honda dealer and maybe get a better read off the cel with a computer.......i assume they can pin point it more that using a jumper... again i may be wrong.

 

hey sorry for stupid question and to be a little off topic but when does vtec kick in for a 4th gen?

 

OP...why do you want to pay a dealer to scan your codes? Auto parts stores do it for free. $0 is better than $95.

 

scanning your computer at Honda will not help you out at all. Ask me how I know. Your code is because VTEC is not wired up.

Unplug the connectors you 'added' for vtec and test drive it. I bet your tach works again. Im willing to help you fix it if your willing to listen to me.

 

Ahh you know what I bet he did hook up one of the wires to the blue tach wire. One of the wires you have to tap into is at the harness right before all the wires go through the firewall to the ecu. I belive its a blie one too. You can get to it alot easier with the fuse box out of the way.

 

can you just answer?

 

I heard my vtec until my motor blew :/