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?

 

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

 

does it smell like rotten eggs?

 

what brand O2 sensor are you using??

 

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?

 

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."?

 

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!!!!

 

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.

 

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

 

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...

 

Doesn't the secondary sensor belong after the cat?

 

<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

 

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

 

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?

 

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..