i read this topic.. and my car has been doing the same thing...
https://honda-tech.com/zerothread?id=50727

how can i splice in the 2nd o2 sensor so that it will run open loop and quit hesitating?... right now the 2nd o2 sensor on the header is just sitting there with the wire hanging out. What do i connect it to?. I have a pr3 ecu and its in a 89 civic si hatch. Thanks

 

How about getting your ECU reprogrammed to eliminate the second O2??

 

Wait, your 2nd O2 sensor isn't even plugged in? Won't that throw an error code for the secondary O2?

 

well the thing is in the header, but the wire isnt even hooked up, the shop that did the swap (which is reputaqble) does this to all the ef swaps they do. I thought it was common, i really am anxious to get this thing diangnosed tho. I was told by derek @ hondata that i could get a rom for the ecu to keep teh car in open loop the whole time. But i want the cheapest easiest fix and this seems like it. aside from unplugging both 02 sensors and running with a code the whole time. So how would i splice the one thats not hooked up into the ecu?

I have never done it and would aqppreciate the help . Thanks

 

Find the wire on the ecu pinout that is for the2nd o2 sensor.
2 options:

1, splice that into the wire from the other o2 sensor
2, run that wire to the 2nd o2 sensor.

I usually do these swaps with an aftermarket header so
I splice the two wires together so it thinks both are seeing the same
signal.

 

Hmmm... maybe I'll unplug my 2nd O2 sensor tonight and try that. I'd really like to eliminate the 2-sensor setup; it's so freakin' redundant.

I've also heard of the 2nd O2 sensor elimination reprogram. I'll see if I can find info... give me a couple minutes here.

Nevermind, I can't find it .

P.S. Does anybody know which O2 sensor we would use as a replacement for the primary? They vary between car, correct?


[Modified by raeneshadow, 6:10 PM 7/10/2001]


[Modified by raeneshadow, 6:18 PM 7/10/2001]

 

it would be grea to find that prgram, i looked under my hood and just didnt feel right unplugging my o2 sensor... i might do it this weekend

 

any pics of what it might look like on a pr3 ecu?.. and what kind of wire would i use? thanks

 

Wonder what the O2 sensor wire might look like, you mean? Like... a wire.

Sorry, I couldn't resist. It's the pinout C8. You'll have to use shielded wire, available at any Radio Shack-type place or hardware store to run a wire from the 2nd O2 sensor back to the ECU, but if you're just connecting the two wires at the ECU any type of wire will be fine (as long as it's short).

Here's a picture of the plugs to help you, read A, B, C from left to right (though I don't doubt you already know what the 2nd O2 sensor looks like). Just remember that the white plug is A, the middle plug is B, the right plug is C (they're in order as appearing while plugged into the ECU):

[img][/img]




[Modified by raeneshadow, 8:07 PM 7/10/2001]


[Modified by raeneshadow, 8:08 PM 7/10/2001]


[Modified by raeneshadow, 8:13 PM 7/10/2001]

 

WTF? Rom? ECU shipping? WTF? How about just running the wire to the C8 position on the ecu and wammmmm......fixed.....Free....Fast......

 

perfect... thats exactly the explanation i wanted, thanks guys although raene, is this done on your car? and it stilll hesitates?

 

It's not done on my car, no. I'm running the stock 2-wire setup as intended from the factory .

I just picked up a MAP sensor and fast idle valve today, I'll be installing those tonight... I'll let you know if it helps (and it only cost $25 for both! )

 

I don't understand why peeps don't just keep the 2nd wire as the Honda (Gods) intended. Why risk any problems? I drilled and welded my DC Header to take the two wires....

 

yeah please post that , lets hope this fixes it... if not, ill try the 2 sensor thingie

 

Nothing, nada, no change. If anything the car ran worse, but then the MAP sensor is not 'known-good'. It also threw a code 7 when I first started it up, saying that the throttle angle sensor was blown (resetting the ECU fixed that, though). I'm going to try the known-good MAP sensor from my brother's CRX Si tonight, but I'm starting to seriously doubt that's the problem...

Inlinefour also IMed me to say his turbo'd Prelude was hesitating like mine was under part throttle, and a new fuel pump fixed the problem. Food for thought...

I was going to pull a fuel pump from the junkyard today as a replacement check, but they wanted $75 for it w/ no warranty so I said screw that... I'll just steal my brother's fuel pump over the weekend or something, see if that works. Maybe he won't notice... heh.


[Modified by raeneshadow, 7:12 PM 7/12/2001]