vtec wont work?

We may earn a small commission from affiliate links and paid advertisements. Terms

9

95silverprelude

New Member
Hey i have a 95 prelude with a 5th gen jdm vtec swap. The harness on the car is from a 4 th gen. Vtec is wired directly into the ecu, which is a p 28. The older harnesses temp senser is located in a different spot than that of the motor. Vtec will not hit. I can hear a small difference but a friend told me it is not hitting that it was butterflying? Would the different location of the temp scensor make v tec not hit. if not any ideas thanks also the other day on the high way i was going fast and the motor was revving at like 6000 rpms where vtec was supposed to hit (that is where it is chipped to hit) and the check engine light came on. i know this has somthing to do with the problem but dont know what it is
 
also remember that vtec won't kick in until the engine is at normal operating temp. so if you have a low temp thermostat in it, that may be affecting it as well.
 
I took the thermestat apart so that it circulates constantly because it was stuck closed. I cut the spring and left the outer rim so that i could use the bleeder in there. would that make it not work. Also I just cleaned the screen and changed the oil and that didnt work.
 
i don't think it would "not" make it work, so long as the engine is running at least 160+ degrees. does the engine get warm?
 
ok the temp senser is fixed, I cleaned the oil screen for vtec, and i changed the oil. I was wondering if anyone knows if it sounds like the electrical components are working, because i can hear the sound of the motor change when i get into the rpm. Sounds to me that the problem is mechanical but dont know what else to check. i know the wires are right except the 2 that get wired into vtec. I have tried switching these and it poped the check engine light.
 
well the sound is probably the secondaries opening, if you are not feeling anything. sounds like the vtec soloniod is not functuning.
 
havent got a new vtec solinoid but had somthing intersting happen yesterday. My car was overheating at a stop. i knew it must be the fans so i popped the hood. I noticed the vtec plug was not on (the one that is circular) i plugged it in and the fans worked. Is this supposed to be like this or is the wires messed up.
 
sounds like your wiring is jacked. the temp switch and the vtec solenoid use the same plug style. the vtec plug is green while the temp switch is grey (at least thats the way it is on my 4th gen).

You also said the CEL came out, what code are you throwing?
 
ner had time to read the codes plus everytime you shut the car it clears the code. what colors are the wires for your vtec plug and the colors of the wires for the temp plug, because both of mine plugs are green
 
ok i was out there lookin at things again, i went on the web. the vtec solinoid is wired right. but he took the wire that he wired from the ecu for the vtec oil pressure sensor he grounded. So i took the wire and atached it to the plug for vtec oil switch. the other wire black i grounded. vtec still doesnt work. with all this wired how it says on the net there are 2 extra wires. these wires when they are touched together make the fan turn. if they arent together the fan will not work. HELP i dont know why these wires are here this isnt a vtec harness.
 
ok i as back out there again i was looking at some ecu diagrams and i think the guy cut the wrong wires. i am going to try to add a pick Should you have to cut anything for vtec or just insert pins. The one hole is open but the other has a red wire in it.
 
The green wire witht the yellow stripe goes to the vtec solenoid. The sky blue wire went to a ground on the motor. I know know this goes to the vtec oil pressure switch. I need to know if the wires that are spliced into are right? The green wire is 2 in from the end. the sky blue one is 3 from the end. Both two are on the row closer to the top of the ecu faceing the camera. Are these locations way. On the bottom pic the blue wire with the red stripe and the black is what make the fan turn? dont know why. So here are the pics HELP thanks
bestviewofecu.jpg
soloidandpressureswitch.jpg
 
it looks like its right.

A4 is the solenoid, and D6 is the pressure switch...if thats how he has it wired then its right.
 

Attachments

  • bestviewofecuedited.jpg
    bestviewofecuedited.jpg
    126.5 KB · Views: 628
how do i know where a4 and d6 are i have looked at diagrams and i dont know for sure if it is right. If i look at the ecu from where the wires go in and have the side with the d, that i have writen on it, up are a4 and d6 on the bottom or on the top. because the wires that are there are on the top. I could be getting confused but it looks like from one diagram that i saw they are suposed to be on the bottom row. Also did you look at the other pic, do you know what the blue and black wires are that are wired to the plug, sorry to be a pain suck at wiring though
 
Yes, D is where the letter D is.

Think of your ECU as being upside down (cause...well...it kind of is).

A is at the top D is at the bottom.

1 is at the floor board and 2 is towards the passenger.
 
ok good then it is wired right i just fliped the ecu to take the picture. I took the wire, that was supposed to go to the oil pressure switch, that he had grounded and just let it hang. no the check engine light is on. Any ideas what the other two wires are
 
im really confused...why did he have that grounded?

the D6 wire should run to the red and blue wire on your engine. it should not be grounded.

the A4 pin should run to the yellow and green wire in your engine. it should not be grounded.
 
You must log in or register to reply here.
Back
Top