JTB

the setup is a 1st gen b16 in a 1990 crx si. the prob is a code 2 and it is very slugish at less that 50% throttle if you give more throttle then is is ok. the code code 2 is a o2 sensor. i have tried 3 o2 sensors but no luck the way i have is wired is only using 1 o2 sensor b/c of the jdm dc2 dc sports header only has i bung.so at the ecu i just branched it off to both pin locations and i am pretty sure this should work b/c i know of a few that are done like this. the cel comes one every few days or so and 90% of the time when i get on the highway. anyone ever heard of this prob? (vtecvillan)?

KMaxwell

i have a similar prob with the same motor but i kept the two o2 sensors, i through code 1 only after driving on the highway. keep me posted if you figure anything out

Newman

Since you have a DC header, you can weld on a nut onto the primaries of the DC header, drill a hole, and paint some high temp engine paint to make it look stock, and screw in the 2nd O2 sensor there. That's what I did a few years ago.... actually welded 2 nuts for the 2 O2 sensors, while I used the original O2 bung on the downpipe for the A/F meter (or I would've just plugged it with a bolt). You want the O2 sensors up higher, at the primaries because the PR3/PW0 ECUs look for the O2 sensors to be warm. If you plug it down by the cat on the downpipe, it takes awhile to warm the O2 sensor up and the car runs like **** & very sluggish until it warms up. When you run a wire from the O2 sensor, run a single, shielded wire directly to the ECU for the best signal.

JTB

thanks Newman! it dosent really run bad when it is cold it actually seems worse when it is warm i ve tried 3 o2 sensors i work at the honda dealership here in wi and we had alot of problems with the ef o2 sensors always being sluggish. i did not run a shielded wire i could not find any shielded wire anywhere and at work we cant even order it through honda. the impression i had for the sheilded is to cut down on engine noise. before i hack up my new dc header that has a perfect coating on it do you think i should still do this since it dosent do it cold? i have done lots or swaps this is the first ef swap i ve done though.

VTECVillain

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Wideopenthrottle+abottle &raquo;</TD></TR><TR><TD CLASS="quote">i did not run a shielded wire i could not find any shielded wire anywhere and at work we cant even order it through honda. the impression i had for the sheilded is to cut down on engine noise. before i hack up my new dc header that has a perfect coating on it do you think i should still do this since it dosent do it cold? i have done lots or swaps this is the first ef swap i ve done though.</TD></TR></TABLE>

You should use shielded wire, that's the OEM way. You need to run the wires to the proper pinouts for both individual O2 sensors. Splicing together one circuit will not work as you've found out. Since it's not right, you basically make it function as if it weren't hooked up at all. Not to mention it could possibly damage the ECU.
Do what Newman mentioned by making a mounting hole for the 2nd O2. You could get away with having the second one on the exhaust piping before the cat if you don't want to mod your header. The main thing is: 2 O2 sensors each with individual wiring going to the proper ECU pinouts.

JTB

cool, thanks alot ill give it a shot!