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02 sensor reading constant 3.8v?!
Posted: Wed Apr 16, 2008 5:57 pm
by Pstl_Pete
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???
Posted: Thu Apr 17, 2008 9:24 am
by Spunkster
Impossible to say without more specific details.
http://www.hondata.net/forum/viewtopic.php?t=3772
Posted: Thu Apr 17, 2008 10:22 am
by Pstl_Pete
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
Posted: Thu Apr 17, 2008 10:41 am
by Spunkster
Do you have a wideband installed?
Posted: Thu Apr 17, 2008 11:56 am
by Pstl_Pete
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!
Posted: Thu Apr 17, 2008 12:15 pm
by Spunkster
You need to enable the o2 heater for the stock o2 sensor.
Posted: Thu Apr 17, 2008 12:44 pm
by Pstl_Pete
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.
Posted: Sat Apr 19, 2008 8:25 am
by Pstl_Pete
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
Posted: Mon Apr 21, 2008 9:49 am
by Spunkster
Posted: Mon Apr 28, 2008 7:01 am
by gee031
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.
Posted: Mon Apr 28, 2008 4:53 pm
by Spunkster
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.
Posted: Tue Apr 29, 2008 12:24 am
by graham031
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.