lvlistchif

sorry for the long message, not as confusing as it looks



ok well i have a turbo kit on my d16y8 with a obd2a to obd1 wiring harness and a p28 ecu, all this is in my 96 civic ex. I was throwing code 21(vtec spool code) as soon as i put my kit on, so i did some reading and saw people did a kinda like 1 wire vtec. So i tapped the wire on my vtec pressure sensor and tapped it into my vtec solenoid wire and when i did i started to also throw code 22. so now im throwing 2 codes instead of 1. The whole problem started after i put my turbo kit on my vtec wouldnt engage for some reason which ended up being because of code 21. so i tryed to bypass the code and wire it directly and now this is happening. it sounds like vtec is kicking in now but im not 100% sure. i hooked it up then did a pull on the road then unhooked and did another pull and i did that like 2 or 3 times. it did feel different between the 2 pulls but im not 100% sure because i cant hear anything over the turbo spool and BOV but it seemd like it pulled a little harder. is there a way to check while driving to see if vtec was actually hitting or not. also is this 2nd code supposed to appear after the rewire? i can see how it would but i figured it would either fix the 1 code or make 2. is this 2nd code ok? also the way i wired it was i kinda just T'd off the power wire from each vtec point at the ecu (solenoid and pressure sensor) and connected them together and i left the ground wire how it was, seeing how it was already grounded.

lvlistchif

anyone?

joelmatt89

I think i had the same problem, when you have a 21 i don't think it will show the 22 then when you wire up the vtec solenoid it will trigger the 22. Which from what i remember is oil pressure at the vtec solenoid... i think. Check your wiring again. Also the best way to tell if vtec is engaging for sure you can tap the wire coming off the ecu for the vtec solenoid, then hook it up to a multimeter. When your driving you should see voltage as soon as vtec engages that's what i would do.

lvlistchif

ok ill give it a try anyone else have any other ideas?

lvlistchif

ok so i took a little small L.E.D light and hooked it up to where my vtec wires meet at by the ecu. and i drove and when i shoulda hit vtec the light didnt come on. now this is very weird because its hooked up where the solenoid is at also so im not getting power to the solenoid or the pressure sensor? does this sound right? i traced the wires from the ecu to the plug and its in the right pin. i didnt have a volt meter on hand so i used the light. is there not enough voltage going through the wire to trigger the light? it was a tiny light and i hooked it up to my battery and it triggered instantly. could this be a deeper problem than just my wiring? im thinking of what wouldnt cause the vtec to engage? i cleaned the fliter on my vtec switch and everything and i took a positive 12 volt and hooked it to my vtec solenoid and it clicked.... anyone help please

lvlistchif

just hooked up my stock p72 ecu and revd it to 4500 then watched the codes and only got i got was 41. no 21 or 22 but could this be because i didnt drive it?

joelmatt89

the light should have turned on if vtec was engaging i think it's a 12v but it is quite possibly a 5v signal if you want to test if it should turn on with 5v your tps sensor among others has a 5v power wire. However if you got a code 22 vtec will not engage. Think of it like this when you reach the right rpm the computer checks a few things one of them being oil pressure which is what i the 22 is. It will not engage vtec if your pressure isn't right. I am going to try and find you a link on here someone has a great write up.

The cel will not come on until you reach the vtec engage point for vtec related codes. You need to focus on wiring the oil pressure switch. Here is a picture of what your looking for

EDIT: Here's that link it should answer basically any questions you have, https://honda-tech.com/forums/honda-prelude-4/official-%22why-vtec-doesnt-engage%22-thread-830163/

lvlistchif

i redid all my wiring for the t'd off vtec and now im only throwing code 21 so i have vtec tap'd off each other and now code 22 went away but still no light at vtec. im so lost

joelmatt89

what do you mean by that(bold).... if you are not throwing any codes and you are sure that you are checking the right wire it has to be the ecu. Could you explain what exactly you did to get the code to go away

lvlistchif

i tapped the pressure switch with the solenoid and code 22 went away but im still throwing code 21 with no vtec engaging