Like the title says I'm in Arizona and my B16a1 failed emissions with a CO level of 2.78.
I've got one shop saying that the problems are probably with ecu and wiring. One of my o2 sensors is disconnected with a jumper at the ecu. My idle is really lopey and my gas mileage is in the 22mpg range.
The shop that did the swap is saying its probably the cat and I should just replace that. Does anyone have diagnostic suggestions?
Does either theory sound more likely?
I need to pass emissions because I already got one ticket and I don't want more. Please help!!!!!!!!!!!!!!!


Also what do you guys think of the jumpered o2 sensor what is the point of that? why not just wire up the second o2 sensor?


Modified by 89EF_Sleeper Si at 3:48 PM 10/7/2005

 

what ecu are you using right now?

 

Good question my car is at the shop and I actually haven't checked. Is there a big difference, and how might different ecus effect performance?

 

Please anyone!?!!! I know I may sound like a noob and maybe I shouldn't even have my car at a shop but I am really busy! I run a custom computer buisness as well as being a double major in csc and math and I need help working this out!
Any ideas would be helpful!
Thank you ahead of time for any ideas you may have!

 

Wire up the O2's properly...thats a given.

 

I'd replace the cat before messing with any wiring. Anybody i have ever known thats failed emissions has replaced the cat and passed no problem. A high flow cat can be had for less than $100, a stock one probably even cheaper. Try that first and if it doesnt work then look at the wiring. Good luck

 

most definetly try a new cat.. i failed emissions with ALL the numbers high really really high, if i find my slip i'll post it.. the shop told me i needed so much **** done and i told them no.. i went and got a new cat made them put it on and i pased with no problems... Gutted cat= failed immisions instant

 

ure lucky, 2.78 CO... Mine was 10.8, getting 11 mpg, sucks major ***. good luck though. try the cat, sounds reasonable, ill try it too.

 

Thanks everyone! The cat sounds like a good start! Man I'm glad my mileage isn't as bad as yours fernruffryders. I have an appt. with the shop that did my swap for a new cat, is there anything else I should replace as a precaution? I'll also wire up the secondary o2 sensor since its not much of an effort anyway!
I really appreciate the ideas!!!!!!!!!!!!!!!!!

 

like was said above, a new cat will almost guarantee you to pass.

Take of the old one, gut it. Put a new one on for the test. Go back home and put back on the gutted one. Save the new one until you're due for emissions again. That's what I did.

I would still fix the wiring though..

 

make sure both o2's are wired up, and going to the correct pins on the ecu.



this will increase gas milage and help with emmisions, and make the car run properly at WOT especially between 3,000 and 5,000 rpm. just do a search here on the crx section for "bogging" if you want to see what you're in for if you try to cheat.

you should then have no check engine lights for any sensors. you should make sure your vaccum lines are all hooked up to OEM spec so the units on the firewall are all hooked up.

basically any corner cutting or little horsepower tricks are going to hurt you here if you trying to be 100% legit with this.

you could replace: the cat, both o2's and even the fuel filter....

you could LIGHTLY seafoam the engine and blow a lot of the carbon buildup out of the exhaust.

if all else fails find someone who likes to get creative if you know what i mean. if you dont, forget that last sentance or ill have to kill you.

seriously tho, good luck to you.

 

Thanks doublethink I'll hook up both o2 sensors. There are no codes however because the shop that did the swap split the line from one o2 into both recieving spots on the ecu. Vacuum lines sound like a likely cause for the lopeing idle so I'll go over those as well.

 

i wonder if that would work if you used a diode, so there was no interference. the ecu would think you had 2 o2s?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ham &raquo;</TD></TR><TR><TD CLASS="quote">i wonder if that would work if you used a diode, so there was no interference. the ecu would think you had 2 o2s?</TD></TR></TABLE>

PRE OBD b16a ecus (pr3 and pw0) require two seperate o2 sensor signals. one collects cylinders 1 and 3, the other does 2 and 4.

you really cant fake it, its best to do what the ecu wants to ensure a clean running engine.

 

thank god i dont ahve emissions or any registrations to worry about after a motor swap!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 89HatchSI &raquo;</TD></TR><TR><TD CLASS="quote">thank god i dont ahve emissions or any registrations to worry about after a motor swap! </TD></TR></TABLE>

word. im happy but at the same time im pissed when i get smoked out by 80s caravan that burns more oil than gas.

 

Holy crap....

Don't listen to anyone who tries to tell you it's the cat. I passed emissions WITHOUT cat at 0.42 co.
Clean running engine and decent gas is the key.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SETI20 &raquo;</TD></TR><TR><TD CLASS="quote">Holy crap....

Don't listen to anyone who tries to tell you it's the cat. I passed emissions WITHOUT cat at 0.42 co.
Clean running engine and decent gas is the key.</TD></TR></TABLE>

yes i agree, it seems like he is just running rich. The cat does help control HC, co2 and nox but its not going to work if you are running too rich.

 

Hey ham just for your reference you wouldn't use a diode you would use a resistor to trick the ecu. It absolutely works I did it with an obdII d16 and passed emissions no prob. The ecu just looks for a specific range of resistance coming from the o2 sensor so a resistor that falls within that range looks exactly the same to the ecu.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 89EF_Sleeper Si &raquo;</TD></TR><TR><TD CLASS="quote">Hey ham just for your reference you wouldn't use a diode you would use a resistor to trick the ecu. It absolutely works I did it with an obdII d16 and passed emissions no prob. The ecu just looks for a specific range of resistance coming from the o2 sensor so a resistor that falls within that range looks exactly the same to the ecu.</TD></TR></TABLE>

the ecu looks for voltage not resistance, you gave it a trick voltage. good idea for a cheap loop hole!

my idea with the diode was to provide two mV signals to the ECU with one o2 sensor. The ECU would think it was receiving the 2 signals. The purpose of the diode is to possibly help with interference, it would only let the current flow the forward direction. so one o2 to c8, then a diode from c8 to c16.

 

You're absolutly right ham, I had a couples beers last night and my brain subsequently farted. What I meant was the o2 sensor creates different amounts of resistance based on the composition of the exhaust gasses. If anything is wrong the ECU reads a voltage that is outside of the "safe" voltage range and throws a code just like you said. All I meant was that the desired resistance that produces the proper voltage reading was not there so the ecu doesn't "see" the desired result. You're right the ecu doesn't look for resistance there's no need for it to, its implied.

You're idea about a diode is a great one I'm going out to the electronics store right now to buy one. The shop that did my swap just put a jumper wire between c8 and c16 and a diode would be an easy way to keep that setup safe untill I have time to wire up the second o2. My car is a testament that your idea works.

 

On the subject of my car problems I cleaned the IACV following the instructions here
http://www.g2ic.com/forums/sho...35534

Then I set the Idle to factory specs and she runs beautifully. To diagnose my idle problem I used this page
http://www.ef-honda.com/ben/ under the tech section.

I'll take her to smog testing tomorrow and see if that cleared it up or if I should still try a new cat.

 

good luck