I have a 92 civic with d16z6 swap in it and a p28 ecu. I ran the solenoid and pressure switch wires to the harness and grounded out the pressure switch according to pics on google images: ground is opposite the clip near the directional nub.

I can't seem to feel vtec kicking in. Every other civic I've ridden in has a noticeable surge as it kicks in. But my CEL from not having vtec wired up did in fact go away.

Also now my battery light came on. No clue why. It doesn't go off when I unwire vtec either. Alternator was putting out about 13.5 volts but now it's either not putting out anything at all and I'm just getting a 12.8 reading from the battery or it's only putting out 12.8. Don't know if they're related.

 

Do you have any cels? You don't really feel sohc VTEC. What does the engine rev to?

 

Cel was on before I hooked up vtec. Now it's gone which as I understand should be a good sign.

How do I tell it's working?

Also battery voltage down to 11.7 while on the interstate. Alternatir definitely isn't charging. Did I blow a fuse ?

I don't see a place for an alternatir fuse under the dash or in the hood. :/

 

Bump

 

If the car rev's up to 7000 RPM's its working

 

92 dx. no tach.

 

No cel=vtec is engaging. You usually don't hear it on a single because the larger lobes are only on the intake side. So unless you have an extremely quiet (stock exhaust w/ cat) you won't hear it.

Did you run the ground back to the ecu? If so, what pin? Whenever I wire vtec I run the solenoid/pressure switch to the ecu and ground the pressure switch to a bolt on the valve cover.

 

solenoid and pressure switch wires are running to orange/white (Solenoid) and orange/blue (pressure switch) on the strut tower plug by the battery. Ground on pressure switch is running to ground wire bolt on the thermostat housing.

 

Your alt is dead replace it before you get stuck somewhere.
Yeah SOHC Vtec is weak and you can barely feel it. If you have a SRI you can hear it if you listen for it.
Keep in mind if the ECU see something is wrong then no Vtec. With a bad alt only giving a 12v system only 11.7v can cause issues until fixed. Also if you hook up Vtec then drove it right away cold engine then no Vtec until the car warms up a bit.
No fun when you go to do a run and your car is cold so you dont get Vtec= slow ET.

 

Well with the battery light on and the battery voltage slowing going down i was 100% positive that the alternator wasn't even charging. However that doesn't automatically mean that the alternator is dead. There are a lot of different components for me to check including the cables to and from the alternator, the cables at the fuse box, the battery terminals, the chassis ground, the connections at the ecu, the tower harness connections, and allure fuses. (I finally found the alternator fuse and it's not blown) if my alternator was outputting low voltage then it would at least show amperage while running. It doesn't seem to be charging at all. I'm going to check all that first.

Anyway, just pointing out ways in which jumping straight to "dead" isn't really a great diagnosis. Despite that I was mainly wondering if there was a way in which I could have messed up the alt while connecting the vtec.

Also I guess I will just have to trust the vtec is running then? In a dohc prelude it makes a very distinct 'vroom' and push around 6500 Rpms. I just wish there was a way to manually engage it or something do that I can test that it's working properly. I don't notice any real difference in acceleration when I get on it hard in first or second, but that just might r my mind playing tricks on me.

 

Ha, I can't believe I didn't add 'Belts' to that list. The alternator belt was shredded, just noticed it.

I guess the only other thing now is wondering if vtec works. But I guess I trust that it does.

 

easy way to check altenator... with the car running disconnect the battery... but unless you're reading 14.6ish VDC with the car running, the altenator is dying...

 

Good trick to know.

It's running about 13.4-5 again now that I replaced te broken belt. So I guess it's on it's way out.
It's a remanufactured alt that's about a year and a half old.

 

Dude I am a diagnosis technician. 99% of the time its a dead alt, but yes there are a few other things that can cause the alt not to charge. Its about a 2 min test to check the alt. Glad you got the alt issue fixed.
DOHC Vtec comes on a bit later than SOHC Vtec and comes on a lot harder. The Y8 Vtec comes in around 4500 or so. The motor will rev to redline even if Vtec is not working it will just stay on the primary intake lob and WILL rev all the way to redline. If you have Vtec hook up correctly, have the knock sensor hooked up (if your ECU needs to see one) and have no CEL then Vtec is working.

 

Def hard to notice if VTEC engages on SOHC. It's non existent.

 

U can go to autozone and they can test the alternator. My explorer was going out and yea they checked it and I got it done

 

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