Luke G.

Ok, here is the deal, i have a obd1 jdm b18c engine, (the jdm engine does not have oil pressure switch) I have a rywire subharness that wires many things in the car including the oil pressure. My question is do i have to wire in the oil pressure wire to the ecu?

go hard jersey

i know this is old but curiouse to what you did. i have a similar situation except that my 800 dollar harness doesnt have the oil pressure wired into the millspec and it should because why would i ever want to have to add to a harness i paid so much for. my situation is a 97 ex w/ a jdm b16. the engine is obd1 an the solenoid has the switch. the harness goes from obd1 to obd2a back to a jumper harness so i can use a p28 and still go to inspection useing a p72. chase did not wire the harness with a plug for the pressure switch. from what i hear i can paperclip d6 to a4.hence completing a path. OR the way i would do i guess(its very complex if u want to keep it looking all the same),is call chase and make him send me the matching lume an heatwrap an a couple millspec pins an a couple ecu pins. from the switch i would take 2 wires and add female pins then secure them into a plug.2) the ground wire i would use the tightest lume for the lenght of the wire(i would ground at the thermostat)and run the power next to it. both wires(1 lumed an 1 not)i would incert into more lume.the end closest to the switch would get heat wrapped.run the same path as the vtec wire. when near the thermostat i would heat wrap again and add a ground,an heatwrap that. the power wire would continue on with the harness (you heat wrapped where the negative went to the thermostat because its a point of stress an thats how he does it,& anytime 2 lumed wires split)continue on untill you get to the millspec,whereas you would add the millspec pin. you would start a new wired pin on the oppisite side of firewall.continue on with lume & heat wrap) untill you reach the obd2a ecu clip(locate whatever the obd2a pin for d6 would meet the obd1 ecu jumper wire)add the ecu pin and heat wrap. tada wired correctly. i know this is like talking another language.those familiar with extensive wiring will understand. this way is how it would have to be done to keep the look of the millspec harness. OR if not concerned about the look. simply at the vtec pressure switch add 2 wires. 1 goes to any ground and the other string it into the fire wall and connect it to pin d6 done.OR LASTLY YOU CAN HAVE SOMEONE THAT CHIPS P28'S INTERNALLY ELIMINATE THE FUNCTION OF VTEC OIL PRESSURE FROM WITHIN THE ECU. ALSO YOU MAY T IN AT D6 RUN A WIRE INTO THE T FROM D6 INTO A4.but if you have nothing comming from the switch to begin with i dont see this working. what did you do? hope this helps someone. this situation sucks for me. if i send it back to chase i might not get it back for 3 months.

Dekorum

If the OP didn't do anything yet: either get a USDM B series vtec solenoid which has a pressure switch on it, and swap solenoids, or keep your solenoid, don't plug in the oil pressure switch from the harness and turn off the function in your ecu when you tune it, which I'm sure you will be doing. Hondata, Krome, Neptune.. you can turn it off with either.

Luke G.

well it turned out that when i did not wire the vtec oil pressure wire into the ecu, i drove it around and had a code. Checked the code when i got back and it was for vtec oil pressure. Even though i was told the jdm motors dont have it. So i wired it to the ecu and i then had no codes, and vtec was engaging.