90 civic wagon. bone stock b20vtec. 2.5 exhaust. ran for a year. head gasket is fresh no leaks.

for about 1.5 weeks now my vtec suddenly just doesnt kick anymore. my cross over is really loud and when it does kick (@5200rpm) your head really jerks back. all my friends know this. so it doesnt cross over anymore and no more sunked seat feeling. ive tried driving slow 1st / 2nd and let the rpm get up to vtec and to 5500 still no cross over.

changed oil with new filter
removed vtec line and cleared it all out with the fittings
removed ecu to see any kinked wires, none.
ecu doesnt smell like it fried or anything.
vtec pressure switch is bypassed on jumper (a4 to d6) (solenoid also has no switch)
replaced whole vtec solenoid setup with my other known working one with new upper and lower gasket.

today, my vtec still isnt working but when i drove to the bank today, (with traffic and idiots brake checking) i switched lanes and smashed in 3rd to hear/feel my vtec again. after that, it doesnt do it anymore..im out of ideas. anyone with information or possibly know what wrong in this situation, please let me know. tia.

 

are you running a oem oil filter or pos filter???

it could be that the oil pressure isnt building up maybe pressure switch isnt working you gotta troubleshoot....also do you have any cels???

 

ive ran the filters from jiffy lube for years. i just changed the oil again too with them. (pennzoil filters i think) there is no pressure switch on the solenoid. its bypassed on then jumper harness and the switch isnt even on the solenoid, just a allen headed screw.

only check engine light is the iat sensor thats it.

 

a cel will make it not work i had a cel for vss and my vtec didnt work untill i fixed it or i bypassed it by using a vafc2 .....also i recomend you using honda oem filters beacuse they are meant to keep the oil pressure up.. other filters arent and its been proven....


also its kinda ghetto that your oil pressure switch for vtec is by passed imo i wouldnt do that at all its there for a reason....

 

but your cel is for vss. that affects vtec. mines been iat since i put the motor into the car and for a fact that doesnt affect my vtec since its been running fine for a year. you bypassed by using vafc2 so thats just in your cause. im obd1 and would like it stay based off the ecu.

the vtec pressure switch was bypassed on the ecu jumper year and half ago. also was done based of phearable.net website since i didnt have the vtec pressure switch on the solenoid anyways.

and as i mentioned ive used the same filters for years. i dont understand really how it would loose pressure

 

im obd1 too i had to bypass it if not it wouldnt work ..

the vtec pressure switch is there for a reason bro.. to engage vtec you need to have 7 psi if not something is causing the clog or your oil pump is bad....vtec work with dowel pins that work with oil pressure....thats why there is an oil pressure switch at the vtec solenoid....

imo i would get rid of the by passing on the jumper, check your wiring, check oil pressure, check valve train, and check your solenoid.....if anything download the honda manual or go buy a manual and trouble shoot it

 

FYI, some JDM Bseries engines came with no vtec pressure switch.

tried another ecu? bad soldering can happen.

 

i will try to find another ecu. the solder looks consistent and no burnt smell. ecu/chip kit/jumper was bought from phearable.net already installed.

 

Id check to make sure the solenoid is working.
test it by applying + - current to the solenoid.
should be able to hear a "click"

Make sure temperature is at normal before trying to engage vtec.

check oil pressure
make sure there's enough oil in the engine.

try another known working ecu.

Test the continuity of the Vtec wires from the switch all the way back to the ecu using a volt meter. Don't have a volt meter? invest in one. it'll help you in the long run working with Honda's.

 

i always warm up my car to operating temp before i even move my car. i made sure my oil was a little under the second dot on the dip stick (top hole) i will try to test the vtec solenoid tomorrow with the + -. will also try to take it to my friends shop to test continuity because i dont have any money at this moment to invest in a volt meter.

 

How do you connect curent to the Vtec Solenoid?

 

You can use wires and run it straight from the battery.

 

 

where do i find my positive and negative connections on these solenoid?