I deliver pizzas and am in my car a good amount of time during the day. When I punch it I've noticed that every now and again VTEC doesn't want to engage. This usually happens after driving for 20 minutes or so. VTEC always seems to work right after starting up. So yeah it only seems to be working for 80% of the time.

I make sure my oil is always at the proper level. I even took off the VTEC solenoid and cleaned it out. It was a little dirty but I am still having the issue afterwords. Any ideas? How can I trouble shoot this thing? Motor is a JDM H22A. Thanks

 

Usually intermittent VTEC engagement problems are oil related. What weight are you running?

 

I run Mobil 1 5W-30.

Could it be a heat related issue? I live in the desert heat, and maybe after driving for a while it simply gives out every now and then because its too hot if i keep trying to hit vtec over and over. I donno just a guess.

Temp gauge shows normal temp, and I don't have an engine light or anything.

 

go to higher weight.... you usually use 5w if your in a colder climate, but your in heat you need heavier oil, try 10w30 you should be a lot better or even 15w40

 

I'm actually up for an oil change, I'll be sure to get 10W30 next time. So could my 5W30 be contributing to the problem?

 

doubtful, i don't think your motor can tell the difference. i think we need more details to point you in the right direction. who did the wiring for the JDM H22A? lets start with that

 

A reputable shop here in Vegas did all the work. I've had the car for around 7 months now and haven't had a problem until the last few weeks.

 

i would agree with dagle, its most likely a wiring issue, i doubt the oil would be related, but try it out next oil change just to check. The temp wouldnt dictate vtec engagement either, since vtec will not work if the engine is not warmed up. its most likely a wiring issue, i would take it back to the shop that did the wiring and ask if they could diagnose the problem. if its wiring, it would be hard to help over the internet.

 

Changing to 10W30 will have no effect. Both "warm" weights of the oil are the same: 30; the only difference in those two is during startup and warmup and neither period is when you are in VTEC. The more I think about it, the less likely it's directly an oil problem. For kicks, you could try 5W40 or 10W40 to find out though, but I doubt it will help.

 

check your connections to the vtec solenoid

 

i had same problem my v tec selenoid wire was too short when engine torqed it would sumtimes tighten up too much and seperate the connection.

 

yeah check the solinoid, that would be my guess. try seeing if it is shorting out

 

clean the screen on the solenoid

 

I cleaned it out but was still having the issue. I'm about to install a new gasket and screen, I'll double check the wires while I do it.

 

Check your oil pressure. Since you said it happens 20mins or so later, the oil may be warming up, which means it thins out, hence less pressure. If I remember right you need at least 57psi for it to engage

 

bad grounds can cause intermittent problems
ya everyone said wiring already but the grounds are a good place to start. take them all off and sand down where they connect. then bolt them back on and see what happens.
my temp gauge kept telling me i was overheating and wasnt. too much of a change in too little of time. them a thermometer confirmed it. checked a few grounds and never had the problem again. just am idea

 

this would happen to me on my lude vtec would kick in a few minutes after it was started then like about 15 to 20 into the ride vtec would shut off. all i did was change my oil pan. it had a tiny indention which probably threw off the oil pressure switch.

 

hondas vtec motor will only crossover into VTEC if and only if certain conditions are met.
1. oil level is at operational standard (may be your problem because as the oil gets hot it may not be enough to engage).
2. engine has not reached operational temp. (or in some cases, temp is too high, this helps prevent heavy footed people from burning out their motor.)

the ecu is set to only crossover if these and some other conditions (which i do not know of) are met.

i'm not calling any of the contributors here incorrect because it may be your wiring at the VTEC solenoid but the common problems i have run across in my lude are the two that i posted above.

happy hunting.

 

This is really starting to bug me. VTEC runs fine for a while after startup. After about 10 minutes of driving I'll do four runs up to fourth gear shifting at about 7000. On the fifth time VTEC fails on thrid gear onwards. I'll try again and VTEC will only engage on first gear.

If i turn the car off and let it sit for a little while. VTEC will work fine for another 15 minutes or so. Then will start all over.

I don't get it. Is it overheating? Wouldn't my temp guage show higher than normal if VTEC thinks its too hot to engage?

 

Could it be that I have not had my oil/filter change in a while? Its been close to 5000 miles. Maybe the oil pressure is on the border of VTEC engagement because of this, yet not low enough to trigger a CEL/Oil Pressure Light? I've usually gotten my oil changed between 3000-4000 miles in the past.

I'm gonna get it changed to day to rule out the possibility.