jonshonda

hello all, i have a question for you that i hope you can answer. I have a 94 Civic Ex with the stock d16 motor with i/h/e. I have noticed that when the car is warm and i approach the stop light and stop, the engine idles down to 1000 rpm , then it jumps up to about 1200, then back down to 1000, and back up to 1200. It does this about 5 times until it finally settles back at about 900.(This usually occurs with my lights and heater on, if that maks a difference) I have a check engine light on and when i tested it code 41 came up. O2 heater. Please help

mwieczorek43

When I had a code 41, I had to replace the whole o2 sensor.
I don't think there's a way to replace just the heater-part. Either go oem (cost alot!) or go aftermarket. Bosche, Denso, Walker etc etc. I personally went with an NGK o2 b/c they make alot of the oem senors for stock cars. And I've been running there spark-plugs for years and years.

jonshonda

I already have an aftermarket o2 sensor and i was told by a honda tech that sometimes they don't work bcuz the impedence of the wires may be different do to the size of the wire itself

B18C5-EH2

It's impossible to trouble shoot an idle problem if you have a defective oxygen sensor, because the sensor itself can cause an idle issue. I'm not guaranteeing the sensor itself will fix the idle, but since it can affect it you need to fix it first since you know it's bad due to the CEL you have for it.

Do yourself a favor and buy a direct-fit NTK or Denso First Time fit oxygennsensor - they are the most like OE, and they plug right in.

Universal sensors suck, and even Bosch plug-in sensors suck for Hondas.

After fixing the 02 problem see if the idle is fixed. If not then there are numerous other problems that can make your idle suck, such as:

1. Low on coolant

2. Bad mechanical fast idle valve or improperly adjusted disc in the fast idle valve

3. throttle body in need of cleaning and idle mixture screw carbon'd up

Numbers 1 and 2 are the most common. If you can't fix the idle after dropping in a good new o2 sensor, post a new topic about your idle problem and IM me when you do so - I'll try to help as best I can via the PC here. I can go into details if need be.

mwieczorek43

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by B18C5-EH2 &raquo;</TD></TR><TR><TD CLASS="quote">Do yourself a favor and buy a direct-fit NTK or Denso First Time fit oxygennsensor - they are the most like OE, and they plug right in.</TD></TR></TABLE>

Yeah ntk is what I purchased, and it worked great. My bad for telling you ngk.... ngk is the spark-plug division, and ntk is the sensor division (i think). At least thats the way it appeared on the box.

B18C5-EH2

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mwieczorek43 &raquo;</TD></TR><TR><TD CLASS="quote">

Yeah ntk is what I purchased, and it worked great. My bad for telling you ngk.... ngk is the spark-plug division, and ntk is the sensor division (i think). At least thats the way it appeared on the box.</TD></TR></TABLE>

You are correct.

jonshonda

Thanks for the help guys. I am puzzled by the idle problem because code 41 is only the code for the heater element on the 02 and should have nothing to do with the idle problem when warm. I am currently looking for the stock exhaust mani with oem o2 sensor. Once i get that figured out i will see how it goes