Still having vtec problems

Smoakie976 · #1 08-25-2003, 04:56 PM

I think that I need a new speed sensor...does anyone know if i can put an sohc speed sensor on a dohc? Same with the vtec solenoid!

kevin808 · #2 08-27-2003, 03:03 PM

Hi,

I read your earlier post about not having your VTech engage, I have a 95 ex, the power is not great, and you got me thinking... "How do I know if mine is really working?" So I was just wondering how you know. Is there a massive power drop off like other cars without VTech? for example... I have a VDub 1.8t also, and it kicks you in the pants between 3000 and 5500, but after that the power goes flat. It continues to accelerate but not compoundly like a VTech car.

Have you compared it to a non-VTech engine?
Does your power fall flat after 6500?

Just wondering..

K808

Smoakie976 · #3 08-27-2003, 07:49 PM

I know because there is a significant change when the vtec kicks in and you can also hear it (on the dohc motors). My speedo is also not working and that will stop the vtec from working...so i was told! I still have power through the whole rev range, but not like it would be if it was working!

B16EJ1 · #4 08-27-2003, 07:53 PM

I am not sure but I am pretty sure that VTEC engagement has nothing to do with the speed sensor. If so the how is it possible to hit VTEC in neutral at a dead stop?

Smoakie976 · #5 09-03-2003, 06:48 PM

That is true, but what if the speedo is not working at all...I was told that it would effect the vtec from working, but it works sometime...like it worked all day yesterday and then it just quit again today, but while it was working I wanted to see if my vtec was working, but it still did not engage.

Also how do you clean out the vtec solenoid? if it is dirty will this keep my vtec from engaging?

I have been dealing with this for a few months now and I am trying to get all the info that I can...I would just take it to honda, but I am shoort on moola! Thanks!

AciDriveHB · #6 09-06-2003, 11:18 AM

As I was told by the person I bought my car off of, my VTECT for my 94 Civic EX 1.6 liter engine kicks in at 4,000 RPMs. Plus doing some reading that makes more sense that it sounds that VTEC is more of a mechanical engage/disengage rather than something electrical. But I could be wrong; I'm still fully trying to understand how VTEC works inside the engine.

Just a thought...
~AciD

track_assassin · #7 09-06-2003, 01:40 PM

have u check the oil level. i got a sohc vtec and sometimes i do hear it kick in. u can hear it better on a dohc. but yea the oil level will affect the actavation of the vtec. i dont think vtec would have anything to do with speedo. my cuz's vtec dont kick in either, and u can tell thats its not kicking cause its a gsr in a hatch and i can keep up with it.

AciDriveHB · #8 09-13-2003, 11:27 AM

Quote:

Originally Posted by track_assassin

have u check the oil level. i got a sohc vtec and sometimes i do hear it kick in. u can hear it better on a dohc. but yea the oil level will affect the actavation of the vtec. i dont think vtec would have anything to do with speedo. my cuz's vtec dont kick in either, and u can tell thats its not kicking cause its a gsr in a hatch and i can keep up with it.

What do you mean "but yea the oil level will affect the actavation of the vtec" I understand what you are saying, but WHY is my question on it? I'm just trying to understand the logic behind it.

And since the mention of oil came up, has anyone else noticed that if you are at higher RPMs (like racing around and what not) that you seem to burn a little oil? Does anyone know why, or how to fix that?

Just wondering...
~AciD

track_assassin · #9 09-14-2003, 02:52 PM

i was talking about something else that is why i used the phrase "but yea" refering to "but anyways".

Jmunk · #10 09-14-2003, 11:18 PM

Wrong, wrong, worng. Activation of VTEC depends on a few thigns. It is dependent on oil pressure. If the oil level is there you may not have the required oil pressure that is nescssary to activate VTEC. Vtec activation also depends on speed. I believe that it is around 11mph for a manual and like 13 or so for an auto for the car to kick in VTEc. I don't know if a VSS (Vehicle Speed Senor) will work off a B series. I would say that your best bet is to get a VSS out of a 92 + civic with a D-series.

Jmunk · #11 09-14-2003, 11:19 PM

Oh if you want to fix the oil burning at high RPM's that you need new valve seals.

B16EJ1 · #12 09-15-2003, 01:49 AM

Quote:

Originally Posted by Jmunk

Vtec activation also depends on speed. I believe that it is around 11mph for a manual and like 13 or so for an auto for the car to kick in VTEc. I don't know if a VSS (Vehicle Speed Senor) will work off a B series. I would say that your best bet is to get a VSS out of a 92 + civic with a D-series.

So you still have not answered why if you're in neutral and rev past the cross-over VTEC is still engaged if it is speed dependent. Don't say that VTEC does not because it's sound is distinct and my VAFC says so. I as well as anyone with a DOHC VTEC who has rev'd in neutral know that VTEC engagement is not dependent on speed.

B16EJ1 · #13 09-15-2003, 01:55 AM

Read up because many people need to really know what VTEC is.........

http://www.leecao.com/honda/vtec/whatsvtec.html

clubcav_com · #14 09-16-2003, 12:04 PM

www.speedstash.com/apexi_vafc.html

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hydrokracker · #15 09-16-2003, 12:39 PM

First of all it is VTEC (Variable Timing and lift Electronic Control) not Vtech. The Vtec solonoid on a SOHC will not fit on a DOHC, or vice versa. The DOHC solonoid is in the middle of the 2 cams, and on the intake side on the SOHC. Vtec is engaged by the ECU when you pass a certain RPM not speed. if it is not engaging then it may be an oil pressure problem (since the system is hydrolic using the lubricating oil of the engine) or the solonoid is bad or if you own an OBDII car a knock sensor problem. if it is oil pressure it can be a few things. 1 not enough oil, 2 car is not warmed up and oil is still thick. if is the solonoid than you need to test the solonoid. put +12v to the solonoid with the engine running and it should make a difference the in the idling of the car if not then you need a new one. if it is the knock sensor then you need to determnie the cause of the knock, may have too far advanced ignition timing, may be overheating, may be running poo gas. if you're knocking you have bigger fish to fry then vtec.
One more thing. When VTEC does engage it should not "kick you in the pants". The ideal engagement point is the crossover of the 2 cam lobes power curves. meaning the high lobe should take over where the low lobe drops off. If your vtec "kicks you in the pants" the engagement is too late and you're losing power. If it is to early the car will bog when it engages. therfore VTEC should not kick you in the pants but if should be a smooth engagement. although you definitely will hear the difference in the engine sound and feel and increase of acceleration, its not like hitting the nitrous button.
By the way I am a honda mechanic. I work on these cars everyday of my life. and I love them more everyday

[92 civic Vx]
If you only knew what it had.........

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