Black R

^ bumping bc I'm having the same problem currently.

I already did the air test and no vtec still.

I pulled the rocker shafts and disassembled and cleaned the rocker arms and vtec pistons.

All three o-rings are in good condition and sealing properly.

I'm stumped.

I think I can modify the vtec pistons to make it easier for oil to get behind them and engage vtec though...

JRCivic1

Black R, did your VTEC failure occur without any modification or did you do some head work, installed the head, and THEN realized that VTEC didn't work ???

Black R

Yes, this is a different head:

I bent valves on my itr head due to timing belt failure at low rpm driving.

To save time I used a spare PR3-4 head and sent it out.
Unknown miles and unknown origin.
The stamps in the head make me think it's an 89 b16 head.

Got valve job and valves, new valvetrain and head was hot tanked and cleaned.

I put the head on and the supercharger at the same time.

No vtec since install, now that I think about it.

Didn't romp on it till I took it to get tuned - that's when tuner said vtec isn't engaging.
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I replaced that center o-ring yesterday (all three o-rings looked mint btw), but when I pressurized the service port, again no locking of vtec.

Also of note is the fact that I thoroughly cleaned and lubricated all the vtec rocker arms and pins - they are perfect.

I started posting in this thread because the OP had done and checked literally everything I have - it's like the exact same issue.

I've even got a spare vtec solenoid on there right now.

The only thing I can think is that maybe there's a difference in the heads internally?

The spare head didn't have spray bars, but it did have cam caps.
I mated them and they fit perfectly - same thing for the center dowel and o-ring and the two oil control orifices.

​​​​​​​Also, when I put air pressure to the head (7gal compressor) starting at 80psi, nothing moves but I hear lots of air hissing out of the cam oil spray bars - I can feel it coming out with my fingers - just like OP.

JRCivic1

The reason I ask is because I had a friend who years ago built a new engine and had the same problems as described here. Turns out the machine shop pulled out all plugs in order to "deep clean" the head casting, and failed to re-install the 1/8" NPT plug under the intake camshaft at the distributor end. We pulled the cam and replaced the plug... the car came alive. Two different shops fought it and missed it... he was at his wits end. He was so happy... 425 wheel HP on pump gas was the result.

Oh, and I don't think your air pressure test will detect this because the oil feed passage is BEFORE the VTEC assembly and therefore before where you would plug the feed and bypass ports... basically only testing for a leak AFTER the VTEC assembly.

Black R

Thank you.

I will check that ASAP.

I was looking at my itr head yesterday just in case there was something different or that I had missed - and noticed the plug you describe.

I will be kicking myself if that's it, but so happy at the same time.

I was going to call Tom @ Portflow and see if he could take my itr head and maybe do oversize valves and then I was going to swap heads again - at least I know my itr head had vtec working!

Black R

^ well I just pulled the #5 cam cap on the intake side and that little hex bolt is there.

I'm stumped.

Whats that other port at the #4 cam cap on the intake side near the edge of the head?

should it be open like that?

JRCivic1

One more possibility...

I remember another guy with a similar problem as yours... no VTEC. It turns out the cylinder head he had purchased (used from an unknown source) had previously been used in a Frankenstein LS/VTEC and the plug was NOT removed in the head that feeds the original VTEC pathway. To verify this, you have two choices: 1) Remove the cylinder head and check the hole in the rear passenger side corner of the head. If it is plugged, you have to remove it for proper VTEC operation. 2) Treat the engine like a LS/VTEC combination and feed VTEC externally using a test feed line between the block and head. There are many ways to create this, starting at the oil pump primary, oil pressure switch port, or a sandwich plate at the oil filter. From there, run a 4AN braided line to the 3/8" pipe plug just above the passenger end corner of the JRSC manifold. I know verifying this sucks... especially for a long shot. But you have tried everything else... what do you have to lose ?!?

Black R

Man I really appreciate your help.

I suppose it's possible that this was an LS-V head at one point - since I don't know the history.

There's no way to see if the internal vtec oil passage is plugged without pulling the head?

I'll research LSvtec conversions bc I'm not familiar with them.

I just want to be able to check by air method.

Maybe it's just that my compressor (7gal craftsman) can't keep up enough pressure to lock the pins?
It does start out at 80psi though...

On a positive note, I talked to Tom @ Portflow yesterday and I think I'm going to send my old itr head out to him for a valve job / new guides, and possible pnp.
He didn't recommend oversize valves - said it wouldn't be worth it for minimal gains.

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HeikDiesel

Have you followed the FSM for VTEC troubleshooting?

Black R

^ yes.

​​​​​​​At this point, it's looking like a mechanical issue - I'm not even testing the solenoid or electricals bc those are known good now.

Black R

If that's the case, then that's the culprit.
No oil pressure is coming up through that passage into the head.

I'm beginning to wonder if mine is plugged also - I don't remember checking it before installing.

The way to check that is simply run an external LS vtec oil line like JRCivic1 suggested.

I ordered the fittings and oil line for that today - just in case.

Black R

Well I tried an oil pressure test gauge on the front port of the head near the vtec solenoid...

Zero psi at 1k, 4k, and 5k rpm.

I checked it again with the vtec solenoid jumped.

Same result.

Next I have an oil filter sandwich adapter and LS-vtec oil line to run.

We will see if that solves the issue...

Black R

Problem solved:



(Held motor at 3500 rpm and jumped power to vtec solenoid with LS-vtec external oil line installed.)


No idea why the air pressure test didn't lock vtec pins previously - maybe because the LS-vtec oil line wasn't there and needs to be there in order for it to work?
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DumpdEJ6

Awesome! Glad to hear the problem is resolved. Maybe you were losing air pressure through the bung that the oil line attaches to?

JRCivic1

Glad to hear you got it figured out Black R.