Rep Power: 0

I have a 7thgen Civic SOHC vtec. For 1 week, when I step full throttle the engine doesn't rev smooth. In first gear, it revs slowly to 4500, then suddenly rev much faster like it has just opened vtec. The worst is, in 2nd, 3rd, 4th or 5th gear again with full throttle, it doesn't rev smooth and also it stops reving for 1 second and continues again through 3000 to 6000 rpm.

I have a VAFC2. I used to tune it like +2,-3.. corrections myself just to try it but now there is no tuning. The problems first came after I tune it to change the Vtec point then turn it back. Now the car revs like it cuts of the vtec for some reason but VAFC2 tells that vtec is open when reving.

Could it be a sensor failure? Did anybody have this kind of prob? Please help!

 
Rep Power: 811

its the vafc. it is not recommended to change the vtec engagement point. if you select four stars **** it will be back to stock and run fine. honda already figured out the optimal crossovers and its never the same each time. if you put it back to stock and still have the problem, you messed up your engine. the ecu uses alot of factors to determine vtec crossover, oil pressure, coolant temp, throttle position (floored gas and rpm above 4500), and sensor voltages. by tampering with it manually, vtec will engage even if there is a problem with one of these conditions. you could also have the controler setup wrong. did you perform the initial setup? is vtec = 3 ?

 
Rep Power: 0

Oh no... You'r right, probably I messed up my ecu.. I turned the vtec engage timing back to stock, everything is back to stock. Vtec = 3, but the problem still continues.
Can't they reset the ECU and solve the problem? Please don't tell me that I should purchase a brand new ECU...

 
Rep Power: 811

well no the ecu is fine i never said that. i said the engine is messed up. if you force vtec at too high rpm and run the engine hard, something must've happened. its not made to operate without a vtec which is pretty much what you turned off by setting it too high. and plus all the other factors, if your engine isnt warmed up, your pressure and coolant temp arent up where they should be and you still have working vtec, bye bye motor.

 
Rep Power: 0

Thanks for the info. So what do you suggest? Can they understand the problem with plugging it to the computer in Honda service area? How will I solve this? Unbolt all the engine?

 
Rep Power: 811

hmm i really dont know what could have happened inside. you could just pretend like you dont know what caused it and see if dealer will fix. but take off the vafc first before taking it in. i am not sure, but you could also try unplugging the battery to reset the ecu to see if it relearns the maps.

 
Rep Power: 0

Check your oil level, i had a oil leak i didnt know about and i didnt have enough oil pressure for vtec to kick in properly. It went in and out of vtec like crazy and ran like crap. Now i have some bad rings. Now i check my oil at least once a week.

Good luck man

 
Rep Power: 245

7th gens dont have a real vtec, 2 lobe design. Vtec kicks in at 2500 to 3000 rpms and thats it. So adjusting vtec is pointless seeing its VTEC-E. If you increased the Vtec to later in rpms it would just take longer to get out of 12 valve econo mode. I dont understand why people are doing these vafc2 contollers on the 7th gens. Were ULEV, stop it people!!!!

 
Rep Power: 0

Thank god the problem solved. Puidokas, after I saw your reply, I remembered that I haven't change the oil for 12k miles. I went to check it and guess what, the oil stick didn't even get oiled...
That was definately the low oil level which cut the vtec. Now it's changed and the car runs great again.
civydcex, you'r right. There is no point changing the vtec point on these cars. I only made that to try and see the vtec kick. Even it's not that much, you feel it kickin' if you change it to 4500 rpm. Of course you loose torque up to 4500; that's why you feel a kick
Thanks guys.

 
Rep Power: 245

^^^ Got to check your oil man

 
Rep Power: 313

WRONG!!!

3-Stage VTEC
Honda also introduced a 3-stage VTEC system in select markets, which combines the features of both SOHC VTEC and SOHC VTEC-E. At low speeds, only one intake valve is used. At medium speeds, two are used. At high speeds, the engine switches to a high-speed cam profile as in regular VTEC. Thus, both low-speed economy and high-speed efficiency and power are improved.

We ARE the ones with the 3 lobe cam design!!!

LINK:
http://en.wikipedia.org/wiki/VTEC

PS: Define "real vtec" for me too civy. Because this "real" & "unreal" vtec talk really pushes my buttons.

 
Rep Power: 263

hmmm I think somebody just got p3wned. Where did U get that info from civydcex.

 
Rep Power: 245

Damn so much for a truce. Typo son!!! Real vtec to me would be what vtec should be, low to high cam lobe vtec switch of power around 4500-6600, which 7th gens dont have, right? D17a2 is an economy, ulev vehical with what should be labeled a ULEV VTEC. Real vtec to me as far as d series goes, anything with SOHC VTEC. That is how it started and now vtec is used for economy not power. Not a real performane enhancing part of the motor and really kind of annoying to see VTEC on my motor when who cares about a economy civic with a VTEC-E, i bought the car for the rims, sunroof, ect. they could of put honda on it like the lx. I have a 04 EX and love it, just annoyed to see people switching a2 heads for vtec on their lx's and stuff. They proboably have no idea that its not the same vtec system we all became acustom to, because of the power ban on the d17a2 is good at high rpm (4000 to 6300)no thanks to vtec!! So thats why I say dont promote something you dont have because these kids probably think their getting some crazy higher reving vtec motor when there getting a 12 to 16 valve vtec activation between 2200-2700rpms wich does nothing for performance except make your car run on all 16 valves instead of the fuel saving 12. Sohc vtec has an actuall increase in intake allowed wich yields a better feel of power and a higher rev to the driver wich is why we all wanted vtec. I gaurentee most people thought they had a good old d series sohc vtec till someone on a forum told them they had a vtec-e, and i bet alot still think their vtec motor is the same as old. It is vtec either way because of the variable timing from 12 to 16 valve switch but just stating there is no extra power or higher rpms from it like older vtecs. I should say vtec doesnt matter in 7th gens, not that it isnt real. But thats how i feal, its my opinion, could care less if you feel like it is awsome to have vtec i wanted a civic for the look and reliability not the crap vtec-e system. Dont get so annoyed over a typo, and i know there is a 3 stage vtec bro, you said there wasnt!!! REMEMBER Its like a D16w8 3 stage vtec and its in 7th gens, just not here.


Typo!!!

 
Rep Power: 811

i put the lx wire cover on my ex.

 
Rep Power: 245

Like it should hve been. I realize we have vtec just not what everyone expected in a vtec i am sure!!! Still love my 7th gen

 
Rep Power: 313

Ok first off all is fair in love & war.

Secondly, I don’t believe that was a typo, at all! I believe it was just an ignorant statement that wasn’t too thought out, and I called you out on it.

Third I also believe you contradict your self in so many ways.

Honda never created "vtec" for power! Never ever. It was just an "idea" to push a car with very little power through its own power band. Coincidently it did make power and would later form into "rice".

Also, you assume WAY too much. I never though I was getting the same vtec as my friends B18. Never ever, I personally do my research before I make any big purchases.

If some one want to swap an A2 head on a LX who are you to tell them they are wrong or incorrect for doing so. People will always find something to fill there time with.

Also why don’t we have a power ban at 4000 to 6300 thanks to vtec??? Vtec is the power ban at 4000 to 6300!!! Also FYI its D16Y8 NOT D16w8. And lastly the 16 valve change over occurs roughly at 3200 RPM stock on the "high" lob of the cam.

I understand this is just your opinion. But understand this, in my opinion it was not a typo just an ignorant statement. Ill see you around man! Have a nice day today!

 
Rep Power: 245

Next time read what i wrote!! I think we got our info from different sources. And this one piises me off,"FYI it's a d16y8 not a d16w8", once again read what i wrote. I said it was a 3-stage vtec version of the 7th gens in phillipennes. Tell me im wrong on that to right!! It was a typo believe what you want. I specifically stated D series vtecs not dohc, that is rediculous Canada. I hope you didnt expect your friends b18!! You try real hard to make me look stupid but i know what i know and typos happen seing the 2 and 3 are next to each other, i always typo ****. I could care less what people do to there a1's good luck . Hope you realize i do know a few things, but if you want to waste your time following me through threads and shitin on everything i say go ahead. I may be wrong on the high rpm vtec in 7th gens i admit, but i honestly think i am right!!! I think you need to check this site, go to http://auto.howstuffworks.com/framed...tec/index.html I think it is rediculous you think vtec was made for economy not power. Its purpose was to increase power across the entire rpm range while saving gas and produceing more power at high rpms. That means power to me. Main point vtec-e is different and labeled VTEC-E for a reason economy. Sohc Vtec is labeled vtec for a reason. I guess you bought a ex for the fuel saving vtec right, not the extra power. You mide as well of got a LX they get better gas milage, or you could even swap the head for the fuel saving VTEC-E right I will agree sometimes i get screwed up when typing but the difference in the sohc vtec and vtec-e were all i was stateing that bothered me. My opinion is crap to most and thats fine with me, but you seem to think everthing i say is wrong. You dont win an award for knowing more than me just this Dont know, but i have a feeling me and you need a beer and a good old armwrestling match, winner can have this argument.

 
Rep Power: 313

LoL!

I am reading what you wrote.

You edited some your original post and add in ulev vtec non sence.

But your oppinion is just as important as any one else.

Where are you from?

 
Rep Power: 245

Bro it was an honest to god typo!! I only edited tha 3 to a 2, seriously look at the posts i only changed the number. I am from rochester, ny. No more bikering, its pointless, you know your stuff and i know mine, absolutly no hard feelings. This is how i am. Even if im not 100 percent ill take a risk of getting called out, it makes socializing so much easier. Nice car by the way

 
Rep Power: 313

New York!!!

Phoenix Arizona!!!

Were at other ends of the world!

Nope no hard feeling!

See you in the threads sir!

O' thanks!

 
Rep Power: 0

Homda civic 7th gen cuts out at 4000rpm
totally agree.
my engine management light came on and the car wouldn’t rev past 4000 without surging.
figured out all along the it was just low oil pressure.
when this type off issue happens people start festering into all sorts of issues and they forget it could be just a simple fix.
the vtec does use oil pressure to work correctly if the oil is low the vtec won’t kick in correctly therefore your eco reads a problem and on comes your light.
these engines are bullet proof I drove one for 35000 miles once with no oil and the engine still runs perfect.
keep the fluid levels correct and they will run for ever.

 
Rep Power: 125

This thread hasn’t been touched in 16 years.

 
Rep Power: 366

hunhhhh, he actually tried to add info, so i don't mind.
but would prefer a date check to happen

 
Rep Power: 132

Neither has his engine oil!