imported_slowandfurious

:cry:
so i failed the etest today, my no ppm was 1000+ and woundering why? Suppose to be under 500ppm. Its a 1996 y7 motor, put a header, and cat back. Woundering if the second O2 sensor might be the problem as i put it before the cat instead of after like the original y7. It has new cap,rotor, plugs, wires, even a new cat. Does not smell of fuel behind the exhaust so its not over fueling, and theres no yellow on the dash. Anyone have any thoughts.

thanx

Tyson09

iTrader: (1)

second o2 sensor shud be behind cat...

chris_si98

how about posting your results so we can tell you if it sounds like an o2 sensor. And why did u change the position of your secondary o2?

bbarbulo

iTrader: (2)

NOx failure is usually a lean running condition or bad EGR.... but a Y7 doesn't use an EGR system as far as I know.

either way, if you have an EL with a Y7 engine... what ECU do you have. if it's the original EL ECU then the maps are meant for 185 cc injectors, and the Y7 comes with 170 cc injectors and that would be the cause of your failure. as for not having a CEL... does the CEL light up when you turn the ignition key to the ON position??? it wouldn't be the first time someone removed the bulb from the cluster.

imported_slowandfurious

sorry been busy for the reply but the y7 is in my civic hatch. I installed a aftermarket headder which had 2 o2 bungs inside it. One was in a primary and the other was in the bottom flange. I just looked at the o2 sensor today and the wires got burnt up but did not throw a code and no light on the dash.(still intact) I have now gotten a bung installed behind the cat and will try the hydrate fluid i read it helps somewhere. The motor is mostly original with original computer. Hopefully putting the o2 behind the cat like the original y7 mani will work. The paper with the reading from the e test i left in the car but everything else passed. Well see if it works
thanx everyone

imported_slowandfurious

So i tested my civic with its y7 again, this time different cat and new O2 wiring set up. Again i failed
HC Limit 75 >Reading 19 Pass
CO% Limit 0.42>Reading 0.01 Pass
NO ppm Limit 576 >Reading 1182 FAIL<<<<<<<<<

So after thinking it threw bbarbulo i think your right. I'll check for fuel and maybe timing cause everything else is o.k. but what a headache. MAybe the new aftermarket header, intake and cat back is starving or scavaging to much and the motor is running lean. I'll try retarding timing and putting on my fuel pressure regulator and see what happens. Also i'll try the methanol, didnt get a chance to run it but will give it a try since its my third time now

Tyson09

iTrader: (1)

please correct me if im wrong but i thought ecu's can somewhat balance if its gettin to much of somethin or not enough.

u did a tune up...maybe check the gap on ur plugs to be correct?

i just passed mine with high numbers, not as high as yours but for me it was my o2 sensor throwin me off but yea give that stuff a go i used kleen flo 2000 somethin...i dunno i guess it helped me

bbarbulo

iTrader: (2)

yeah there are fuel enrichment tables the ECUs go to for extended injector pulsewidth when the O2s detect lean condition... but it's hard for that to be any good when you've modified your air flow capabilities with an intake or exhaust system. also if the ECU thinks your injectors are bigger than they are...

also I was wrong about the injector size, it's actually 180 cc for the Y7 and 240 cc for the Y8.

imported_slowandfurious

Anyone think if i put y8 injectors on the y7 motor will it fix the problem? Will i have problems with over fueling and will the computer be able to compinsate?

imported_bananax

Hey hold on 1 sec

so an EL 1.6 SOHC VTEC motor comes with larger injectors? and the one from an SI comes with a smaller set? what would happen if you used an SI ECU with an EL motor? I'm getting pretty ****ty milage on my SI currently and I have an El motor with an SI ECU, no CEL light though. unless the last owner yanked the bulb

imported_slowandfurious

Well the EL and si both use y8 motors, the only difference which i have heard and dont know if its true is that the el and civic use different cam profiles. Other than that they are both the same motor's, and probibly the same computers.

bbarbulo

iTrader: (2)

no, the LX, DX, CX, SE models come with the small injectors...

bbarbulo

iTrader: (2)

the injectors and the ECU have to match. Y8 ECU, then Y8 injectors... Y7 ECU, then Y7 injectors. unfortunately, i don't think there is an easy way to tell the injectors apart. I have both sets, and at first glance I don't think I can tell them apart.

chris_si98

No

It's the same motor, cam's are the same

Tyson09

iTrader: (1)

your temp gauge reading normal?