I have a 2001 accord v6 coupe. When the car first gets up to operating temperature, everything works fine and the vtec engages instantly at 3.5k, but after a while of driving, when i need to accelerate the vtec doesn't come on and around 4k the engine sputters a little and then the vtec eventually works. when the sputtering occurs, the check engine light flashes and the code is for misfire, and is happening on all cylinders. Then engine also knocks and had a turbo before i had it, but has been returned to stock. Maybe a mod done to work with the turbo is still there and is messing something up? And since it's only after a while maybe a cooler thermostat would help? I have never heard anything else like this and am wondering if i need to have the engine rebuilt, the vtec solenoid replaced, or if i should just sell it to an older person who won't drive it like that anyway, because it drives perfectly fine under 3.5k. any opinions appreciated.

 

You should never feel the v-tec kick in. I think that it engages at a much lower rpm (~2000 rpm).

If you have the actual code (P and four numbers), post it on here.

 

Vtec goes off of oil pressure, not rpm. If you slam on the gas the oil pressure will build before the rpms get high and vtec will engage. If you slowly let the rpms climb it wont engage until later... If the car used to be turbo'd, there could be many reasons why you are having problems... Does it have the original ecu in it???

 

Vtec is activated by the ECU through the input of several sensors. It doesn't depend on just the oil pressure. EDIT: Oops, made a mistake. I was tired and not thinking when I wrote this. There is a pressure sensor that is on the vtec unit. If you read my last post, the ECU will store an error code when the check engine light turns on. Have the code read and post it on here.

Vtec uses oil pressure to lock the two intake valve rocker arms to a third rocker arm. That third rocker arm allows more lift on the intake valves to get better performance at higher rpm.

 

when i first start driving, it kicks in at 3.5k every time i accelerate hard. after a while it doesn't kick in at all, and it feels like it only has 50hp or so from 4-5k, until i get through it then it takes off again and the check engine light starts blinking. during the time it feels slow i can hear popping sounds. i'm thinking the turbo messed something up, but i'm going to have the vtec solenoid inspected first. my guess is that possibly something in the valve train is messed up and not all the cylinders are getting the vtec rocker arm locked in, so some cylinders are making more power than others.

and i don't know if it's the original ECU but i have never seen an aftermarket ECU for the J30A1, but i could try resetting it. the guy that used to own it was very serious so it's probably tuned, but i've never met him, he had it two owners before me, just heard about this car from a friend that knew the guy

If nobody has any idea what's wrong, i'm thinking i'll just get the top end rebuilt

 

Stop by a parts store and have them read the code(s). Post them on here. It may help to figure out what is wrong with your car.

 

there are actually no codes right now. the check engine light only blinks when the problem is happenign, then goes away. i'm going to take the car to a tuning shop and see if they can find something that was not converted back when the turbo was removed. they have a turbo s2000 project right now they should have experience in that area

 

I have a 99 Honda Accord Vtec My car does the same thing. I finally got it to the shop and got codes. P1259.... They still have NO idea what the prob is... Just that Its the Vtec UGh!! I have tried hella stuff and still dunno whats wrong

 

You don’t need the check engine light on to get the code as the computer stores them. As you were advised go to one of the parts stores that offers the service of retrieving the codes for free such as Autozone.

 

donno if this applys to v6s... when CEL pops vtec wont engauge...