I failed emissions today and am trying to figure out not only why but what else is going on with the vehicle.
Specs: 93 hatch
b16 stock block, SIR II headcrower 401's, vafc, p30ecu, greddy sp2

I think the main problem is the cat is just worn out, its not rattling around or anything, but the body has damn near 150k on it and i don't know how long that cat has been on there...
The next question is about the 02 sensor and wiring. While idling the sensor read 350mV constant, with a WOT blip going to a max of 500mV....seems wierd that its not varying at idle and going rich at WOT...can anyone maybe provide me with some insight to this. Also if anyone knows where i can find some info on the 02 wiring...on the 02 section of the harness there is a white, green and 2 black wires...and on the chassis part of the harness there is a black, white, green and yellow wires. In most vehicles the 2 black wires are for the 02 sensor heater and are power and ground...not here.....

 

bump

 

I am presuming that you are measuring the O2 voltage when it is warm and that you are tapping into the wire at the O2 sensor (although using streaming data from a scan tool is ok but you can't eliminate the wiring running to the computer as being faulty).

Your O2 sensor is just plain dead. It should be swinging from about .2 volts to .8 volts when the engine is held at about 2500 rpm (roughly). If you womp on it the voltage should immediately jump up to .8 - .9 volts.

Replace the O2 first and then you can see if the cat is working or not because the cat is not going to work properly if the O2 sensor is dead.

-Scott Tucker

 

thanks man....i figured it may be the o2 and am currently looking for one...not sure what year/model to order it from though....and yes we were probing at the o2 with a bed of nails on the meter...

 

Cool, let me know how it turns out and if you need more help.

 

haven't replaced it yet, but something i was thinking about that i thought was wierd was if the 02 was giving out a lean condition (due to bad o2 or not) that would command more fuel...but the plugs show that i am way lean, yet the emissions readout is rich

 

Don't rely on reading plugs they only tell extremes. The base fuel map on your car is probably pretty close anyway. Do you have the CO, CO2, HC, 02, AND NOx readings from the printout?


Modified by AutoEng2002Si at 4:34 PM 1/5/2006

 

Please post your emissions readings.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hazw8st &raquo;</TD></TR><TR><TD CLASS="quote">Please post your emissions readings.</TD></TR></TABLE>

I second that

 

first test...went there vehicle cold on a one mile trip and got right on
test/ limit
CO: 1.28/1.10
HC: 273/275
NO: 2830/3600


second test after some hard laps around the industrial park...thought it would've gotten better

CO: 1.42/1.10
HC: 320/275
NO: 4142/3600

 

I don't see why you couldn't use any primary 4-wire ECU Honda employs. Sure, new is best, but it never hurts to try an old one if you have one lying around.
B

 

i would definetly try if i had a spare one lyin around

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by new2novas &raquo;</TD></TR><TR><TD CLASS="quote">first test...went there vehicle cold on a one mile trip and got right on
test/ limit
CO: 1.28/1.10
HC: 273/275
NO: 2830/3600


second test after some hard laps around the industrial park...thought it would've gotten better

CO: 1.42/1.10
HC: 320/275
NO: 4142/3600</TD></TR></TABLE>

You're running too rich. If the fuel mixture is leaned (more correctly brought closer to the stoichiometrically correct mixture, most cars for emissions run stoich at 14.5:1 not 14.7:1) out I believe all the readings will come down and into spec (unless you have a bad cat). The hard part is figuring out what is causing it. O2 sensor is definately a prime suspect and you can test it with a digital volt meter (like you did, good job) or just replace it. You don't say whay RPM and if this is a loaded test when you gave the specs, can you clarify that?

 

yeah it was on a dyno, 15mph at around 2200rpm...we came to the same conclusions you did about possible bad cat or o2, still haven't gotten a definite on what year/model to get an o2 from...thanks guys

 

O2 sensor and catalytic.

 

thanks guys...still need more info though on getting the correct o2 sensor

 

Have you check 2 see if your O2 sensor is responding?

 

yup...check my first post

 

Yup, just reread it. If you have any CA smog/registration related questions, email me.

 

thanks guys...a new magnaflow high flow and new o2 later and it passed with flyin colors

 

Congratulations! Glad we could help.