VTEC not engaging

[Mike1357]

I recently completed the auto to manual conversion in my car and, since completion, VTEC has not engaged. At first I thought it was because the speed sensor wasn't working, but I had fixed that earlier today with the same result. I am running a p13 ecu and still using an automatic engine harness. Any ideas?

[dj_ender]

Are you still running the auto P13? Any CELs?

[Mike1357]

Yes, p13. I could be wrong but I think p13's are only auto (anyone know for sure? ).

Alright, 5 codes.
12 - EGR
17 - Vehicle speed sensor
21 - VTEC spool solenoid valve
23 - Knock sensor
36 - traction control (apparently a JDM ECU thing)

The EGR is no longer installed, I replaced the VSS today so that may be an old code, I accidentally unplugged the VTEC wire so that may be an old code, no idea about the knock sensor and traction control (apparently).

[kratemertyl]

If u think those are old codes reset the ecu by disconnecting the negative cable and pulling the ecu fuse. Let it sit for about 5 min. The p13 is available in both auto and manual but that's about all I know in regards to the ecu.
The vtec works off of a hydraulic system and a electrical system. Unless u have heavy sludge build up in the motor or very low oil pressure it will be an electrical thing. Luckily the ecu codes will point u in the right direction. Clear the codes and go from there

[dj_ender]

Most people leave the egr plugged in, but tucked out of the way. 3 of those codes will prevent VTEC. And I would suggest getting a USDM manual ECU.

[jdm_inspired]

I have a JDM P13 and no theres manual ECUs. You may need a USDM if you have emission laws where youre from. I may not need my P13 but I'll let you know within the next few days.

[Mike1357]

Did the reset. 12, 23, and 36 are the current codes. VTEC still is not engaging. The knock sensor is tripping most likely because I have ESP mounts. I'm going to try a friend's p28 and see if it makes a difference tonight. Until I get my own I'm still wondering what is causing the issue.

[wagon-r]

Alright, 5 codes.
12 - EGR
17 - Vehicle speed sensor
21 - VTEC spool solenoid valve
23 - Knock sensor
36 - traction control (apparently a JDM ECU thing)

A VTEC spool solenoid valve code will cause the ECU to disable VTEC engagement.

EGG, VSS, and traction control codes will not. Re VSS, VTEC engages based upon engine rpm and load, not vehicle speed.

I'm not sure about the knock sensor. I'd be surprised if a knock sensor code would disable VTEC, but it might be possible.

[dj_ender]

Pretty sure the ECU needs to see a speed reference for VTEC to engage.

[Mike1357]

Like I said earlier, the only current codes are 12 (EGR), 23 (knock), and 36 (traction). This still doesn't explain why it's not engaging.

[4GAccordH22]

I'm pretty sure that a knock sensor code will disable VTEC. Knock sensor is an engine safety device. EGR will NOT disable VTEC. I drove mine for a few hundred miles with the EGR code and VTEC still worked fine.

[Mike1357]

I think it has something to do with the 36 code. It's been my experience that knock plays with timing. I tried a chipped P28 last night; it doesn't throw any codes and VTEC engages like it should, so its not a mechanical or electrical issue, it has to be something in the ECU itself. I'm just wondering if there's a way to jump a signal or make a jumper to get that traction control code out of the system.

[4GAccordH22]

You do realize that the D16Z6, which uses the P28 does not have a knock sensor, don't you? So when you swap in the P28 you are bypassing the knock sensor. Did you check the wiring to the knock sensor? Fix the KS problem and I would bet that VTEC will start working. You should try to clear codes as a first step in troubleshooting anyway.

[Mike1357]

I wasn't sure if it was either deleted from the ECU or the ECU didn't have it. I'll have to check the wiring tomorrow. Happen to know the pin location on the ECU for the knock signal? And I had already cleared the codes once. I know far more about OBD2 diagnostics than I do the older stuff. At least in the cars I work on, variable timing isn't disabled when the knock sensor starts going wonky so my mind didn't go to that first.

[dj_ender]