h22ek9forme

I have a h22 in a 96 ek hatch

so I bought the car about 3 weeks ago with vtec not working,
the car was on a p13, but the car had no knock sensor. so no vtec
I also had chipped p30, with uberdata,then tried crome, then I bought a phearable chip.
all of them had the knock sensor disabled still no vtec, no CELs what so ever, just no vtec.
so I wired a test light on the solenoid wire from the computer, and when vtec is supposed to engage it lit up. so that was confirmed, then I wired the solenoid directly to power with a switch in it, drove it and flipped the switch.... still no vtec. (the solenoid was clicking like it should), so I am thinking oil pressure, ****.
I decide to say screw all the BS, and bought a knock sensor so I could run the p13.
I went and bought a new map sensor,VSS, and coolant temp sensor.
got the knock sensor in, wired it up, went for a drive,
and now instead of nothing, right when vtec is to engage the car completely shuts down, wont accept anythrottle or anything. so after waiting 10-15 mins, it would start back up again.
that problem lead me to the coolant temp sensor, bc I read that if you try to engage vtec when the car is not at opperating temp it will do exactly like mine did.
now the temp sensor on the thermostat housing was unplugged, w/ no plug in sight.
then I read about having to convert the plug style, and saw my square plug that needs to be a round plug, changed the plug, hook it all up, go for a drive,
and it fckin dies again when vtec is supposed to engage. before all this when I had no symptoms besides just not having vtec I was realy thinking oil pressure, but if the oil pressure was not how it should be, that should trip the vtec pressure switch and throw a CEL right? I got no cels at all.
I have been trying to figure this out for a week now, and I was completely lost before,
but now with this problem I feel I have something to diagnose.


HOPEFULLY some one in all of honda-tech would know why it shuts off when vtec is supposed to engage.

please help!!!!!

h22ek9forme

....................

H22 TREX

h22ek9forme,

Sounds like you have already performed some good preliminary checks, like verifying the VTEC engagement voltage is reaching the VTEC 1P connector. The ECU shutting down when the VTEC should engage is symptomatic of the ECU feeling a short circuit/ground.

I recommend you unplug the VTEC solenoid and drive the car past 6000 RPM and see if the car shuts down again. This will help isolate the problem to the VTEC circuit.

The VTEC solenoid has a big loop of wire inside whose resistance should read between 14-30 OHMS, measured between the gray 1P connector and body ground. The solenoid wire insulation may be breaking down, measuring good when cold, then short to ground when hot, or when it actuates. I would check the resistance of the solenoid when cold and hot. If the solenoid reads outside of the designated parameters, remove and replace.

The solenoid could also be malfunctioning internally. You may hear the click, but the mechanics might fail to operate properly. An internal moving part may be striking the solenoid wiring and shorting it to ground, temporarily sending the ground (0 OHM) signal back to the ECU, causing a temporary shutdown. When the VTEC voltage is removed, the mechanics would return to a static state and the ground would go away. So it's possible the VTEC solenoid is shorting out to ground (0 OHMS) when it engages, but measures normal (14-30 OHMS) when off.

With VTEC, the ECU is set up to drive a 14 OHM load which would use about 1 amp of current at 13.8 VDC. If it grounds out to 0 OHMS, you are now drawing BIG amps, shutting down the ECU. You could use a clamp on current meter to see how many amps the VTEC solenoid draws when engaged; this would tell you how many OHMS the coil reads under load. If the solenoid draws over 1 amp, remove and replace.

I would try and avoid the ECU shutdown situation as much as possible to prevent possible permanent $$$ failure.

Good Luck.

Later

h22ek9forme

I will do that.

thank you for your help