Just happened tonight for the first time. In second and third gear as i enter vtec the engine seemed to stutter. This did not happen in first gear. I filled up gas today and i am suspicious that i may have gotten a bad tank. Would i recognize the sound if it was detonating? I think i will go buy some octane booster tomorrow. How should i go about diagnosing this safely?? Any help would be much appreciated.

 

detonation you can hear little pings and knocking noises

 

bump

 

are u starting like on the freeway, going from low 3rd and just gasing it till it hits vtec? or are u shifting thru 1st,2nd, then 3rd lags out ?

 

i dumped in some octane boostet today and that seemed to help, but didn't eliminate the problem. I'll pull the plugs tonight and take some pics.

 

i pulled the plugs and they look alright... gap seems ok and they have some reddish brown residue but no white or black spots. i'm leaning more towards injector/fuel pump at this point.

 

5 things are needed for VTEC to function:

-Temperature: The engine must have reached normal operating temperature.

-Throttle Position: The throttle must be open far enough to allow for increased airflow in VTEC.

-Vehicle Speed: The car must be in motion (wheels spinning).

-RPM: Engine must spin to it's target value.

-Oil Pressure: The engine must be operating with normal and safe levels of oil pressure determined by the VTEC pressure switch.


If you aren't getting VTEC to engage, one or more of those things is not working properly.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by TheGSRGuy &raquo;</TD></TR><TR><TD CLASS="quote">-Oil Pressure: The engine must be operating with normal and safe levels of oil pressure determined by the VTEC pressure switch.</TD></TR></TABLE>
The VTEC pressure switch does not determine whether or not vtec engages. The vtec rockers are operated by oil pressure, and if the engine oil pressure isn't high enough when the vtec solenoid opens, the rockers will not engage. It is a mechanical issue. When the solenoid opens and the pressure is high enough to operate the vtec rockers, this pressure also opens the vtec pressure switch, opening the VTM circuit, which verifies for the ecu that vtec successfully engaged. If the ecu powers the vtec solenoid and the pressure switch does not open, this activates the CEL and the ecu stores the vtec malfunction code.

 

oh snap i forgot to mention that it's not throwing a cel

 

well... 4 new platinum ngks and a new rotor seem to have taken care of the problem.

 

could have told you that!

 

^^ a little late! haha

 

yo, i have a h22 vtec motor, my vtec isn't working properly i dont think. you seem to know alot. so i'll throw this one at you. i've been having trouble, im hitting a rev limiter at about 6500 rpms, that's no good, and vtec isn't working. i haven't had a CEL at all, so yesterday i got it up to 105 and the light came on, i checked it and its code 21, (vtec pressure switch) i believe that is good, kuz i've had it off and cleaned it, solenoid works also. i believe there isn't enough oil pressure. do you have any suggestions what could cause that. i appreciate ANYTHING MAN I NEED HELP THANKS.

 

I would suggest replacing the pressure switch first and seeing if the problem goes away. Bad oil pressure could be a nightmare.

In the mean time, don't beat on your car too much.

 

well goin back to the original problem he had thats almost the same problem i have right now.... no CEL car is at operating temperature wheels are moving its at the right rpm and all that good stuff and vtec was poping but die'ing out and now it doesnt pop at all and the ecu is giving out voltage to the vtec solenoid and its a h22a motor as well i dont know whats goin on

 

 

fix the codes - egr and oxygen sensor

 

 

if the a/f mix is wrong it effects whole engine operation