I posted this before. I was going to bump it but couldn't find it. My VTEC stops kicking in after 15-20 mins of driving.

First we thought it was the wiring and we rewired the entire thing. We took the solenoid out and checked if there was anything blocking the filter, it was fine

I thought maybe my oil cooler went bad or something and it was making the oil thin, but i have a defi oil pressure gauge and the pressure is fine. even when the vtec doesn't kick in, it is at 80-85psi. I have oil in the car.

We checked the AEM when it was on the dyno. AEM is showing VTEC "ON" even if it doesn't kick in so basically it sends the signal.

Anyone have any idea what it might be? I don't think the solenoid is bad because I have VTEC for the first 15 mins but it looks like something gets hot and causes the VTEC not to work

 

I'd probably replace the solenoid and start with that. Just because the AEM says its turned on doesnt mean the solenoid actually activated.

 

yea but if the solenoid is bad, shouldn't i have no VTEC at all?

 

VTEC solenoid is an electromechanical valve. THe ECU can only tell when the electrical signal is being sent to the coil of the solenoid. The mechanical side is unknown to the ECU. The valve may not be opening (sticking) even though it is being told to open.

 

yea but what i'm saying is, why doesn't it do it right away? i have VTEC when I first start the car. But if i drive for like 15 20 mins, i won't work. if i stop the car, wait 20 mins, then i again get VTEC, then of course i lose it after a bit...

 

heat?

 

try unplugging the vtec controller from the beginning, when its cold. see if it does the same thing as when it gets hot. Then try a continuity test of the lines... try running a voltimeter to the wire (run the wire into the cabin) drive around, and then when it starts doing it, see if there is the same voltage going to the solenoid. There might be a grounding issue where it gets hot and increases the resistance on the lines.


My friend has the same issue, Ill PM you his screen name and maybe you guys can shoot questions off each other!

Problem solving with my friends, we thought it might have something to do with the head... Maybe a sticking vtec pin? have you pulled the cams and had a look at the pins to see if any get stuck etc? I know you said the oil pressure is still good with the oil cooler, bu what if you disconnected the lines and tested it again?

 

Exactly what I'm thinking. The solenoid could be sticking only when it's hot.

 

Thanks Jon, I'm having a simialr issue with my car as well. Car will make no power and hit what feels like a rev limiter after a couple mins of driving. Car will pull strong to redline when cold but as soon as its warmed up or after the first pull it will hit what feels like a wall at 7-8k. I've had this issue from day one of the turbo install, 6 months and counting.

We believe we've narrowed it down to something in the head . I've replaced almost every sensor in the motor, minus the knock sensor with no results. Seams like its directly related to heat.

Batikan, I sent you a pm but figured I'd add the info to this thread as well.

 

even though I have no VTEC, mine doesn't feel like it is hitting redline. I can still rev it up to 9K but it accelerates really slow and runs crazy rich becayse the injectors are dumping all the fuel as if the car is making more power with VTEC where it does not