darkstarbd

Hi

recently I rebuilt my B16 with forged crank, rods, Hi-comp pistons. upgraded the valvetrain and cams. I am running Apexi PowerFC for B16B.

The thing is, VTEC is set at 5900rpm. after 5900rpm, i can see in the apexi display that vtec is on but cannot really feel it. as the motor is still in break-in, i am not pushing over 6500rpm yet. but there is no significant difference before and after 5900rpm. No CEL/codes are showing.

Can anyone please help me with suggesting whats wrong/how to diagnose or fix this issue?

hoffmanb16

Hitting Vtec in the break in period? Is that a good idea?

5speed4life

Yes.


As for your issue, there could be a bunch of things.

Make sure your afc is hooked up right, Trace your wiring directly to the solenoid, and make sure it's a good circuit, not shorting to ground or positive. Check resistance of the wire, make sure it's in good shape.

apply 12v directly to the solenoid when the car is off, make sure it clicks. If it does click, Rig up a test lead inside the car, and apply 12v at 5900rpm. If it still does not change, you may have a mechanical issue.

Do you have an oil pressure gauge? If not, why not? If so, watch the gauge when vtec is supposed to activate. You should drop a little bit of oil pressure. If it's a lot, (like 20psi or more) then you have assembled the rocker arms/shafts wrong. It is possible to put the rocker arm shaft in backwards and not notice it, however it will cause vtec not to work, and a considerable oil pressure drop.

Make sure that the vtec solenoid screen/filter is not cloged.

Make sure that you have the o-ring installed underneath the #3 cam cap.

Double check your LMA's for excessive wear/sloppiness, and re check your lash.


Those are just a few ideas to get you in the right direction. If anything on that list strikes a cord, start there.

Vtec is sweet when it works. When it doesn't, it can be a headache. Especially on a fresh motor where you have to rethink everything you did.

N/A

Since when is hitting vtec during the break in good???

Don't think u should be taking it over 5k during break in, I know they say drive it hard to seal the rings but that seems too hard

darkstarbd

Its not AFC, its PowerFC. it is wired right. it was there on the stock motor before working 100% ok. checked with a test lamp and at 5900rpm, the test lamp was turning on, indicating wiring to the solenoid is ok.

applying 12V directly gives the 'click' sound. i changed the vtec engagement point to 3500rpm and still doesnt change. so what mechanincal issues i might have?

Yes, i have oil pressure gauge. but it is hooked up on the oil cooler as no space near the oil filter. so i know it shows a little bit less pressure but i adapt. even like this, i have 20psi pressure. there is no drop of pressure seen when vtec supposed to be on. rechecked the rocker arms and cam holders and cam holder plates. everything is the way it should be.

checked. no clogging.

checked. its there.

whats LMA?

just so you know, i have a brand new head, manufactured by procomp.

Mr. EG

LMA= Lost Motion Assemblies

darkstarbd

checked... they are within tolerance

93egSLEEPER

Break it in how you will drive it. Hell I break my motors in on the dyno if possible.

PyroProblem

You didn't mention if it was tuned or not yet...What are your a/f's when your supposed to be in vtec?

Top Ramen

- any codes?
- what is your oil pressure right before crossover? (won't activate if it's too low)
- double check your oil level. (I know this is simple, but I have seen it happen many times, and it will prevent vtec engagement)

darkstarbd

As a have an aftermarket head, i want to check if oil is flowing through the vtec solenoid. how can i do it?

mikesrex

you can measure the oil pressure if you have a pressure gauge and a way to connect it to the head by the VTEC solenoid. look further into this on a google search and i'm sure someone has pics or something.

mikesrex

PS there is an oil pressure switch located on the VTEC solenoid that tells you if you have enough pressure to activate VTEC.

darkstarbd

there is no VTEC pressure switch in my car. (some JDM B16s dont have it)

mikesrex

dang well that is one less thing to use to troubleshoot. if you have a spare VTEC solenoid with a P/S maybe you could put it on there to troubleshoot.

N/A

That's prob your problem, get a solenoid with a oil sensor

darkstarbd

My car never had a vtec pressure switch to start with. Some JDM models don't have VTEC pressure switch.

darkstarbd

the car doesnt have vtec pressure switch from factory. so that means there wouldnt be any connection to C15 pin on the ecu. so how is it gonna help?

the thing is, when the motor was stock, vtec used to work. now after rebuilding it isn't working anymore. there is no CEL or code (my CEL is not broken btw).

i havent tuned the car yet as i am still breaking it in. afr is around 14 and around 12 at 5900rpm when vtec supposed to kick in. oil pressure is always over 20 while on load. oil level is perfect and oil is also new.

5speed4life

Lol...

The first thing I do with a build after checking oil pressure and bleeding coolant system is to take it to the moon (usually with ~10psi of boost (I like boost)). If you built the motor right, it will last and be better for the motor in the long run. If you failed to keep your build area clean/uncontaminated, or your clearances are wrong, or just over all mistake, then the failure is going to happen quickly.

Pussyfooting a motor around for 500 miles is just going to delay the inevitable if the motor wasn't right in the first place. "Man the first motor I built and tried to break it in hard only lasted 20 miles... so I rebuilt it, gave it a 500 mile break in, and this time it lasted 520. Breaking in an engine slowly is much better..."

Either way, engine break in is a touchy subject to most, and has been covered countless times. The only definitive answer to what's right is what you feel most comfortable with and works for you.


DarkStar, how much oil pressure does your gauge show at 5900 rpm? Also, are you 100% positive you used a b16/gsr head gasket? Can you watch your oil pressure gauge while someone else activates the vtec solenoid with the car running?

Was that your cylinder head that you sent in to have the work done, or did you buy it outright?

I'm just saying, you should see your oil pressure needle move, even just a little bit when the solenoid opens. Even if the rest of the vtec system is not working. If not, then there is a clog somewhere. The vtec solenoid's oil supply is a direct shot from the block. If you accidentally used an LS head gasket (witch would work. It's not right, but it will fit and the engine will run) The oil feed for vtec would be blocked by the gasket. Also if you bought the head outright, and the head used to be on an LSVTEC, the cylinder head may have a plug in it where the oil feed comes through the block to the head.


Without pulling your head, the easiest way to make sure you're getting enough oil to the vtec solenoid would be to plumb an external oil line. Do a little research on Lsvtec oil line, and set your motor up the same way. You will not need to plug the oil galley in the head/block (especially if it's already plugged).

N/A

Where did I say ***** foot it?
Like you said touchy subject, everyone has their ways so I'm not gonna get into it, but I have only had 1 of my reworked engines fail, and it had nothing to do with break in

I did not notice your location, thought your car was usdm

DDTECH

Wrong. Drive it hard.....usually within the first five mins of a motors life, the rings are almost sealed.. so.. its a ASAP thing to beat on it..
Some people break their motor's in easily, and it works.. sometimes. If you want constant results you beat on it.


To the OPS problem. Lets make sure vtec is working. If you could jump a wire from the battery to the vtec switch to hear a "click" , we'd know your noid is working. From there i'd look to make sure you have the right ecu, and if it is the right ecu, that you have a vtec ecu. On JDM motors, vtec won't kick in, if the speedo isn't working, or the coolant isn't "hot" enough.. or operating temp.. list off these things.. and check your oil.

you should see around 10-15psi @ idle and 30-40while crusing. @ wot you should be 80+

HondaPartsHero

https://honda-tech.com/forums/hybrid-engine-swaps-18/%5Bfaq%5D-%22my-vtec-doesnt-work%22-1812135/

will show you how to do the oil pressure tests

5speed4life

I dont think any newly built engine failure is due to break in procedures, honestly. If the motor is right, it won't break regardless to break in procedure chosen. Mainly just how well the piston rings seat/seal. That's all.

5speed4life

I doubt it's any sort of electrical/ecu issue. The same setup worked before, and he didn't mention changing anything.

He has already checked the wiring to the solenoid, and checked if the solenoid clicks.

I think the problem is in the head.

darkstarbd

I totally agree with you. everything was working fine before with same ecu/wiring. i took out my motor, rebuilt it and put it back in. the wiring is fine, solenoid is clicking. i am also thinking it is the head as it is aftermarket. but the thing is, i am from Bangladesh, and there is no way for me to get a hold of a low pressure gauge to check the pressure. can i plug in an oil pressure gauge sensor there and try to get reading out of it?