Help Please!! check engine light on don't know why

[philyphreak2127]

Okay so I just swapped my motor. I had the d16y7 in my car when I bought it but I threw a rod and found a decent deal on a d16y8 with the ecu. I have yet to put the ecu in because I planned on buying the wiring harness for the y8 rather than running my y7 harness. I got the car back yesterday and decided to go driving. I drove for about 2 hours and the check engine light came on....I'm confused. So I checked all the easy stuff to check. I made sure the mass air flow sensor was correctly in my cai, I checked the vaccum lines, checked all the fluids, checked the sensors on the intake manifold and can't find anything wrong. any ideas?

 

[BrutalB83]

Did you figure out which code it's throwing? That would probably be the best thing to do. Also, are you using a VTEC controller or are you just running with no VTEC for now?

Oh, one more thing, are the harnesses really that different? I can't believe they would be. I would have thought you would be able to just use the Y7 harness and add in the VTEC wiring and that's it. Am I wrong?

 

[philyphreak2127]

the vtec wiring is all that is different. that is what I meant I'm not going to change out the ecu til I have the wire to wire up vtec. and as for the ecu codes, how do I check the code it is throwing? sorry to sound like a dumbass but I learned how to work on old cars

 

[BrutalB83]

There's an article on how to check ECU codes in the reference section here. Let me see if I can find it...

EDIT: Found it, here it is: https://hondaswap.com/reference-materials/88-ecu-error-codes-29109/

Just follow the directions in the first part of that write-up and figure out which code(s) you're throwing. Then, reference them on the list in that article and you might able to figure out what's causing the problem.

You can also just take the car to Autozone; they'll plug in a scan tool and pull the codes for you for free. Don't take it to the dealership unless you want to spend $50-$100 just to find out what's wrong with your car.

 

[philyphreak2127]

thanks man. you are a big help. I was freaking out...the y8 motor I bought had like 90,000 miles on it when I bought it. I was like shit this motor isn't any good which could still be the case.

 

[93civicracer]

it's probably just a bad sensor

 

[philyphreak2127]

thats what I am hoping for.

 

[RDY2RACMY]

this may sound really stupi but did you check the gas cap?... no really, i forgot to put it on one time and the check engine light came on!!! i was on a 700 mile road trip... so i took it to a shop and they read it, it was a cheap $7 fix.... check it out..^_^

 

[philyphreak2127]

I did check that lol. I always try to fix my issues with my car easiest solution to hardest. I checked the gas cap, then the oil cap, radiator cap just in case, checked to see if the vaccum lines were connected, the mass air flow sensor on my cai, the vaccum line running from the back of the valve cover to the intake, all the little things first. Could running a non-vtec ecu with a vtec motor do it?

 

[RDY2RACMY]

ya that could set it off, but... if it were you would really feel it in the top end of the car... it would make the new engine feel about the same as your other one.... so the best thing to do is have the code read.... it will tell you for sure

 

[philyphreak2127]

I planned on it today but it snowed. bald tires + lowered ride = 2700 lb sled

 

[Koop]

great thread!!!

 

[ek9jdmguy]

i can tell you right now your non vtec ecu is throwing out a code due to it not being to identify where the vtec is even comin from....just swap the ecu and check to see if it still comes on.....

 

[93civicracer]

Well first off the EASIEST way to check what's wrong is grab a paperclip and jump the ecu that'll tell you right away. It's most likely the IACV that'd be my very first guess. That's the ONLY code I have left since my swap and the funny thing is my car idle's perfectly fine even tho I still have that code showing up.