vtec malfunction

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sniezek66

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I recently did a swap on a 90 honda accord with a h22a vtec engine. Car runs great except the vtec is not engaging. From the wiring diagrams i got off hear it's pretty sure i have them pinned right to the ecu. What i'm getting is a constant ground from all three sensors even when the vtec is supposed to engage. What i was wondering is what sensors are supposed to send a positive signal to engage the vtec. The car is also throwing a check engine light , but i'm unsure of the code. I did not hook up the IAB, just ran a straight vaccum line. The black wire coming off the vtec solenoid is also grounded correctly. I have tried three different ecus with all the same results so i know the ecu is not the problem. Thanks for any help.
 
sniezek66 @ Apr 28 2006 said:
Quoted post[/post]]
I recently did a swap on a 90 honda accord with a h22a vtec engine. Car runs great except the vtec is not engaging. From the wiring diagrams i got off hear it's pretty sure i have them pinned right to the ecu. What i'm getting is a constant ground from all three sensors even when the vtec is supposed to engage. What i was wondering is what sensors are supposed to send a positive signal to engage the vtec. The car is also throwing a check engine light , but i'm unsure of the code. I did not hook up the IAB, just ran a straight vaccum line. The black wire coming off the vtec solenoid is also grounded correctly. I have tried three different ecus with all the same results so i know the ecu is not the problem. Thanks for any help.
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Wha ecus are you using. A 90 is a obd0 car And you would at least need a obd1 ecu to run vtec. Also a jumper harness.
 
also you might wanna check your CEL....not really sure how you do that on an OBD0 Accord, but definitely need to know what that code is.
 
Yes the ecu is obd1 Also i did not use a jumper harness i just pinned the ecu for the vtec. Tab got the diagrams for me on which ones to pin. Pretty sure i have it right. Does the vtec oil pressure switch always feed a positive signal or negative??
 
good question...i always forget that one.
 
test your oil pressure, then look at other things. I'd double check your wiring, and make sure all of your connections are made properly. VTEC wiring will kick a CEL if you hit VTEC range without engagement. Read that code.

I looked in the manual, but it didn't say what was positive, or negative. However, I'm willing to bet that most things are grounded negative. So the ECU probably just reads resistance, ground, or no ground. I doubt if you will have any positive voltage to read on the VTEC wiring, except for the solenoid.
 
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