B Dap

Alright so i jsut got my swap in

94 dx hatch
b20b bottom - stock
p72 gsr head - stock
p72 ECU - stock - will be chipped soon

Run's fine without the vtec hooked up and when we hook up the vtec it runs like crap. It barely revs up, runs really rough. I had a similar problem with my b16a and thats why i swapped it out. I'm driving it around without the vtec. Also im going to be sending my ecu out to me chipped. I will be having the knock sensor removed. But the thing is...its not even throwing the knock sensor code!

Also when all of the vtec stuff is hooked up the check engine light stays on. Even when we try to jump the ecu. the SRS light will flash and the check engine light stays on.

It cant be the wiring harness because we hard-wired the vtec lines right to the ecu. Previous owner of the motor said vtec worked fine. I traded him the b16a for this b20b and he has no problems with vtec.

Only codes im throwing are: #21

Honda guru's help me out!

low_n_loud_civic

See what happens after you get it chipped.

B Dap

Thats what i was praying for lol. It just seems like someone doesn't want me to have vtec

xxstuntin4life

it sounds like a wiring problem in ur harness.. if ur jumping to check ur codes and ur srs light is flashing not ur check engine then u def. have a harness problem somewhere

xxstuntin4life

btw u wont ever hit vtec if ur throwing a code 21(vtec solenoid) def. check ur wiring and make sure u have it hard wired right

mrharmonic

yea i agree i have the same set up but im fully built but i have a 95 dx hatch and it runs great also, has to be the harness.

B Dap

Ok but heres the thing. When the vitec wires arent hooked up it runs fine. When we hook them up it runs like complete as. We just ran new wire for the Vtec wires. re-sodered them...all that. When its hooked up it runs but when i try to give it any throttle it just dies, and thats when i cant jump the codes. When we unhook the vtec we can jump it just like normal. I have a 92-95 ex/si harness, but that shouldn't matter anyways because it runs fine without vtec. Its when we hook it up that things dont work. So by getting this ECU im hoping that everything will work out accordingly. If not a new wiring harness will be the next purchase.

xxstuntin4life

well its either ur hooking up the vtec wrong.. are u sure ur running them to the right pin out? or u have a messed up ecu.. wat pin's are u running vtec to?

B Dap

Off the top of my head i believe its A4 and D6. It did the same thing with both ecus and i know forsure its not that because the p28 was out of a perfectly running car...

mooeys racing

x2.... i had a ls vtec set up and when it was one the stock ecu it didnt do any of that, i had a ecu chipped for my set up by pro function and the car runs great...

B Dap

Why would it only do that when Vtec is hooked up tho? I can check the codes when its not hooked up. The vtec wires are completely seperate from the wiring harness in this situation. We hard wired them. The knock sensor isn't hook up...and the b20b is an obd2 block if im correct. Could it make it run that badly to not even jump the codes? Doesn't really make sense but figured i'd ask.

But even so if the knock sensor isnt hooked up wouldnt it throw the code even if vtec wasn't hooked up?

B Dap

Up

mooeys racing

do you know that your EUC is good??

B Dap

I used my stock p72 and my buddies P28 that i know works and it did the same exact thing. Except the p28 made my car idle at 2500 rpms.

HondaPartsHero

can you take a picture of where you are hooking up the VTEC wiring both at the sensors and at the ECU?

B Dap

Yea i can do that for you. As far as the ECU part do you mean the Pins? Because its A4 and D6... i guess im unclear on what you want but i can just snap a pic of both for you.

ja20_eg

hey bro i think its ur wiring on ur pin on to ur ecu..that motor was HITTING VTEC when it was in my car...if anything u can give me a pm on ht here...ill try to help u out what i know..yep still got ur swap on my stand...swap not in my car yet..TOO COLD!!!!lol...just waitting til spring n save some cash..too TURBO it...hit me up anytime bro...

Jimster480

I think that you are connecting VTEC to the wrong pins, or you read the diagram wrong. Because it sounds like your causing a short in the ECU when you plug in VTEC. You can test the solenoid by giving it 12 Volts and ground on the top sensor wire (not VTEC Oil Pressure Sensor). But it doesnt sound like a solenoid issue.

B Dap

We tried the pins both ways just to make sure. I have a ground comng off of the solenoid aswell....I gotta get those pics for HondaPartsHero to.

bar'dh22

something in the wiring is messed up or when you do the jumper trick the srs light wouldnt blink maybe your main harness is messed up

Jimster480

the SRS light blinking means there is an error in the SRS system. It has nothing to do with the motor.

B Dap

I think he misread what i said. The SRS light blinks like normal everytime. Its just when i hook vtec up that the CHECK ENGINE stays solid. When unhooked it reads perfectly fine.

HondaPartsHero

I just wanted the pic of your ECU because when I first started doing swaps back in the day, 2001 my first swap I pinned it according to a diagram but was looking at the ECU plug from the "female" side and was pinning it backwards, on yours it should look like this if it is your wiring on the ECU side should be good

B Dap

Well i will deff. look into that! im hoping its some stupid mistake i made like pinning it wrong! ill let you know. Those subharnesses look sweet to! I might pick one of those up from you once i get some extra cash. I guess i should ask to. Does it matter what gauge wire im running for the vtec wires? i think its like a 18 or 16 gauge(dont quote me on that).