f_l_g

i have now thrown the 2nd 02 sensor in before the cat. i hooked it up to a datastream monitor and the 02 sometimes won't spike at an idle. my CEL keeps throw a 61 which is a b1s1 slow response code. This has to be something with the wiring. any suggestions on how fix this? it is making my car run real rich and it runs like **** and i can't stand it. I'm running a 99 si with a STOCK b16a in it. Any of you honda masters wanna help a fellow enthusiast out?

Padawan

Can you elaborate a bit on what exactly you've done so far, for those of us who aren't familiar with your issue?

-JSpecEk*9-

does it smell like rotten eggs?

sicones

what brand O2 sensor are you using??

f_l_g

I'm running denso oem type sensors both are brand new before the cat and after. i just replaced the catalytic converter with a magnaflow obd2 carb legal cat within the last 500 miles. I just replaced the wiring harness from a 2000 si. everything is legit and i have spent countless pondering hours about this and i am finally stumped does anybody know how to check the continuity of these wires and what plug they go to?

EE_Chris

Did you have to wire the connectors onto the O2 sensors....or did they come to you with a connector already attached?

This is just a stock 99 Si, right? Why did you replace the entire wire harness from another 99 Si? If you didn't, then what did this mean: "I just replaced the wiring harness from a 2000 si."?

f_l_g

ok the wiring harness i had was hacked all to hell and every wire was but connected right before the ecu, so i bought a 2000 si wiring harness and replaced the current one so i had all the connectors in one piece. its a brand new cat so and it doesn't smell like rotten eggs. if i clear the code the car runs bitchin but as soon as the ecu re-maps itself it kicks the code and just gets worse and worse and i am getting horrible gas mileage. everything is new and the sensors are oem replacements with plugs straight from denso. i have no other clue... HELP!!!!

f_l_g

when the car is hooked up to the datastream on a scanner the o2 voltage bounces back and forth +/- voltage but zeros out every 30 seconds or so. when i lay off the throttle the sensor flattens out for about 3 seconds or so. Is this normal? I am running way too rich and am getting horrible gas mileage.

f_l_g

P0133 Rear Air/Fuel Ratio (A/F) Sensor (Bank 1, Sensor 1) Circuit Slow Response
This is the breakdown of the CEL.

sicones

thats the secondary O2 sensor, are you using a universal O2 (the one you wire with butt connectors)??

I would take out the cat and look through it again just to make sure...

redsled00

Doesn't the secondary sensor belong after the cat?

sicones

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by redsled00 &raquo;</TD></TR><TR><TD CLASS="quote">Doesn't the secondary sensor belong after the cat?</TD></TR></TABLE>

yes

f_l_g

cat looks good, no they are not universal 02 sensors. straight from denso, does anybody know how to check the wiring on these?

crx378

yeah i had to use universal and now i cant get rid of p0131 low voltage code
dont see why your plug and plays are giving that much trbl. just a question though. are you sure you put the right o2's in the right place or does that matter, same part numbers?

geebs

B1/S1 is the upstream sensor.. ie before the cat.. a slow repsone code can be set from exhaust leaks or a faulty sensor.. just because its new doesnt mean it works 100%.. ive seen it happen many times.. im sure there is a wire connector diagram for the o2 sensors somewhere in a helms manual or the honda manual.. or you could also sign up at hondahookup.com and download the honda manual..