How can you tell VTEC is working????

m3power222 · 4 February 2003

Maybe you all can answer this, I just got a 91 NSX but I'm not convinced the VTEC kicks on after 5800rpm.
You should be able to tell by the tone of the engine right? I know with civics and integras you can.

I checked the check engines codes and it returned a 52 (rear VTEC pressure switch). I reset the computer
or whatever it is and it didn't return the code again nor did the check engine light come on as it did once
and a while.

Ojas · 4 February 2003

VTEC transition is less noticable in NSX than other Hondas.

check the FAQs

Quote from this page:

[JM] How to tell when VTEC is kicking in? Here's a nice indirect way I learned at NSXPO. Watch your oil pressure gauge as you rev up through 5800 RPM. The VTEC system consumes a significant amount of oil flow when it is activated, and you can watch your needle FALL a couple of notches as the revs climb through that point.

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ojaspatel.com/nsx

m3power222 · 5 February 2003

I saw that article, but I don't see my oil jump up to 6. People have said on this forum they are around 6 when the VTEC kicks in.

Larry Bastanza · 5 February 2003

m3,
The oil pressure will DROP once the VTEC activates

. If you see no pressure drop about 5800rpm up, then they may not be activating. There can be a few causes for that. Fill us in again on exactly what happens if you take the car, let's say in second gear and go from 3K - redline. What's the oil pressure gauge doing??

HTH,
LarryB

Andrie Hartanto · 6 February 2003

If your rear VTEC switch is faulty, you will not have VTEC. What's the rev limiter kicks in at? When my swicth fails, My rev limiter is around 7K rpm.

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Larry Bastanza · 6 February 2003

Andrie,

Wasn't there another thread recently with someone talking about limiting rev at 7K?? Maybe in the FI forum?

Thanks,
LarryB

Andrie Hartanto · 6 February 2003

Hi Larry,

I'm not aware on the thread you mentioned. Maybe you can provide a link?

Thanks,

nsxhk · 6 February 2003

Correct me if I'm wrong, but wouldn't the engine check light comes on if vtec doesn't kick in after 6k?

m3power222 · 6 February 2003

I redline at 8K. The engine light was on before, but I reset it and it hasn't come on. But when I check the service code it did come up with 52 that points to the VTEC Pressure Switch.

As I go up the RPM range, I don't see any movement in oil pressure. It stays at 4.

Shouldn't I hear a pretty different sound from the engine after VTEC kicks on? Also shouldn't I feel a boost? I don't get any of those right now. This is the only NSX I have ever had or driven so I have nothing to compare it too.....

Ojas · 6 February 2003

There is not much of a difference in sound when in the VTEC range... I think the transition is very subtle, hardly noticable. Just look at the torque curve of a stock engine (notice how much more linear it is than that of a GS-R or B16 motor):

So, if you're coming for the 4 cylinder Honda world, I can understand why you'd ask about the VTEC.

However, I think if for some reason your VTEC was NOT working... You'd really notice it: Engine would starting running out of breathe before you even get to 8000 rpm. No?

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[This message has been edited by Ojas (edited 05 February 2003).]

[This message has been edited by Ojas (edited 05 February 2003).]

m3power222 · 6 February 2003

I do think I noticed the "out of breath" once. I punched it and at 7000 rpm it was like I hit a limiter. That was only one time. Everytime I take it to 8000 it has no problem.

Don't get me wrong the car is fast. Maybe I'm just comparing it to 4 banger VTEC's.

Does anyone else on here have any experience with this?

m3power222 · 6 February 2003

Just now my check engine light turned on and it redlines at 7K.

I turned off the car and restarted it, the light was off and I am able to redline at 8K.

My guess is VTEC pressure switch is going bad and sometimes works and sometimes don't.

MiamieNeSeX · 6 February 2003

Originally posted by Larry Bastanza:
Andrie,

Wasn't there another thread recently with someone talking about limiting rev at 7K?? Maybe in the FI forum?

Thanks,
LarryB

That was me, I replaced the Speed Sensor and it fixed the problem

nsxhk · 6 February 2003

So I guess I'm correct.... the check engine light will come on.

DanO · 7 February 2003

Originally posted by Larry Bastanza:
Andrie,

Wasn't there another thread recently with someone talking about limiting rev at 7K?? Maybe in the FI forum?

Thanks,
LarryB

If you look at Service Manual page 5-7 you will read the flow chart that shows all the variables that need to be satisfied for the valve timing change to occur. These variables are: Engine RPM between 5,800-6,000 RPM, vehicle speed 3 MPH or faster and water temperature 140oF or higher. If one or more of these conditions is not met, then the “changeover” (e.g. what we some call VTEC) will not occur and the engine RPM will be limited (probably around 7k).

Compared to an Integra type R, the NSX VTEC changeover is much smoother, less noticeable and less dramatic. I expect if something is wrong with your VTEC system, a check engine light would come on indicating a problem with the spool valves since these are what control the oil pressure to the VTEC rocker arm changeover pins.

DanO

D'Ecosse · 7 February 2003

Originally posted by m3power222:
... As I go up the RPM range, I don't see any movement in oil pressure.
It stays at 4 ....

My O.P. gauge is at 7+ @>3K rpm

[This message has been edited by D'Ecosse (edited 06 February 2003).]

nsxhk · 7 February 2003

My oil pressure stays at 6+ as long as I'm accelerating regardless of inside or outside vtec range. At 7k or 8k rpm, my oil pressure stays high above 6+ without dropping a bit.

m3power222 · 7 February 2003

As long as I have had it, it has never been past 4. I've only owned it for 3 weeks. So maybe the VTEC has been going out on it for a while. The VTEC pressure switch anyways.

DanO · 7 February 2003

Here’s a similar topic and some good pictures and descriptions of the NSX VTEC and VVIS system…
www.nsxprime.com/ubb/Forum1/HTML/003969.html

NSXnBRLA · 7 February 2003

I started noticing the difference in sound at VTEC, when I installed a cold air intake on my car. Its very evident when you hit 5800 RPMS now.

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BostonNSX · 12 February 2003

you mean rev at neutral or actually run the car at 8k? I cant rev the car over 7.2k at neutral I think

NSXnBRLA · 12 February 2003

Originally posted by BostonNSX:
you mean rev at neutral or actually run the car at 8k? I cant rev the car over 7.2k at neutral I think

Why on earth would you wanna rev that high in neutral?

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VTEC Forums- The newest online discussion center, for Honda performance.

BostonNSX · 13 February 2003

By mistake.

I've been trying out my car today
it tries to climb to 6-7 on oil but when rev hit around 6k . it dropped somewhat under 4 k..

Originally posted by NSXnBRLA:
Why on earth would you wanna rev that high in neutral?

nsx_parts · 14 February 2003

M3Power222:

I live in Portland, Or. You can drive my car as a comparison. Private me.

Did you buy Eddie's car?

Bryan

m3power222 · 14 February 2003

I'm pretty sure it's working now. Looks like it was a funky connection at the VTEC pressure switch. I just disconnected it and reconnected it.

Thanks for the offer for letting drive your car.

Who is Eddie? I got the car from Ron Tonkin Grand Turismo.

How can you tell VTEC is working????

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