02 sensor reading constant 3.8v?!

Pstl_Pete · Post by **Pstl_Pete** » Wed Apr 16, 2008 5:57 pm

Im stumped...why on earth does my 02 sensor read a constant 3.8V at idle on the dash?

Shouldnt it be a 0-1v output? Is this a simulated wideband reading? if so how do i turn it off?

Oh once the car is warmed up and moving the voltage varies but still above 1v so Im confused how this is possible???

Post by **Spunkster** » Thu Apr 17, 2008 9:24 am

Impossible to say without more specific details.

http://www.hondata.net/forum/viewtopic.php?t=3772

Pstl_Pete · Post by **Pstl_Pete** » Thu Apr 17, 2008 10:22 am

Engine is an OBDI JDM H22A with stock fuel system in a 95 Honda Accord, P30 ECU with S300, brand new 02 sensor just installed

Post by **Spunkster** » Thu Apr 17, 2008 10:41 am

Do you have a wideband installed?

Pstl_Pete · Post by **Pstl_Pete** » Thu Apr 17, 2008 11:56 am

Yes I have an AEM but it is not hooked up to the Hondata. A/F is around 14.4-15.0 at idle and crusing.

PS - Thanks for the help!

Post by **Spunkster** » Thu Apr 17, 2008 12:15 pm

You need to enable the o2 heater for the stock o2 sensor.

Pstl_Pete · Post by **Pstl_Pete** » Thu Apr 17, 2008 12:44 pm

when I do that it throws a CEL. If I leave closed loop off no check engine light. So I def shouldnt be reading that high a voltage right? it should be 0-1v.

Pstl_Pete · Post by **Pstl_Pete** » Sat Apr 19, 2008 8:25 am

here is another log with the car driving. The sensor seems to read properly when i the 02 heater is on but i still have the check engine light.

Why is that? Could it be a miswire on the harness? Hasport did my harness conversion but I can double check it if you can provide me what pins to look for.

thanks,
Peter

Post by **Spunkster** » Mon Apr 21, 2008 9:49 am

http://www.hondata.com/techwiringgsr.html

gee031 · Post by **gee031** » Mon Apr 28, 2008 7:01 am

I am having what sounds like a similar problem using smanager 1.3.1 The car is a 91 civic VTEC from the UK.

Using a stock new 0-1V O2 sensor, closed loop either engaged or not, it outputs 3.8V all the time in the sensors window, but using a PLX wideband and the O2 heater turned off it reads spot on to the PLX display. We would like to use the stock o2 sensor and closed loop eventually.

Post by **Spunkster** » Mon Apr 28, 2008 4:53 pm

What do you mean by a stock 02 sensor? A 91 CRX would have had a 1 wire o2 sensor and does not have the wiring for a 4 wire heated o2 sensor.

graham031 · Post by **graham031** » Tue Apr 29, 2008 12:24 am

Sorry, had to change my username to log in at work,

Sorry for the confusion, i didnt give the most information i could, its a 4-wire o2 sensor, the car has an obd0-1 conversion harness to run the s300.

I think i answered my own querstion anyway by looking at smanager in more detail than when i was rushing a little on saturday. Would i be right in thinking that in sensors & parameters it is only the wideband input that you are monitoring & setting up respectively? You never actually monitor the 0-1V narrowband input, it just takes care of itself when in closed loop.

Its ok, the guy is going to get a PLX now, and from using mine in the car we know that works, so it should be fine.