My car is equiped with the single wire oxygen sensor. The problem I am having is the Diacom reading at idle and up to about block learn cell 6. What happens at idle is the block learn slowly works its way ip to 160. Once it reaches that # it starts idleing rough.(it sounds like its loading up and occasionally the IAC starts jumping up and down and makes it surge like a fueler) The O2 sensor reads as low as 13mv and pretty much stays below 100. I pull the plugs, and they are fairly brown. The block learn stays fairly high untill cell 6 where everything settles to (+-) 128. I checked for intake leaks several times and had "profesionals" check and scan also. I am running TPIS ceramic headers (with air pump) high flow cat and aftermarket mufflers.
TPIS also burned the stage V chip.

At first I was scared to drive it, but after seeing the dark plugs, I drive it everyday. I'm starting to thing the O2 sensor isn't staying hot enough at low RPM's. It doesn't always have the extreme low O2 sensor readings. Sometimes its perfecly normal, but eventually it gets to 160. Once there the intergrator normalizes to around 130. It feels rich.

The question is (finally) what happens to the O2 sensor when it isn't hot enough? I was under the impression that it would not kick on and leave the ECM in open loop.

Should I go to a wideband and how do I wire it?

Could it be the chip? I want to have it reburned by one of you guys cause I think TPIS's burn is to conservative.(I eventually want to learn to burn myself) I also thought that the chip was just to lean down low hence the 160, but there seems to be plenty of pulse left in the injector to compensate.

I wanted to post this many times but haven't had the chance. Any thoughts or ideas or if you just want to pick on me (like my car is doing to me) please do.
The car runs pretty awesome otherwise. Needs some slight tweeking for "normal" driving and reads really rich at WOT with not alot of timing and rarely a knock count.

I have talked to a number of "profesionals" and always get conflicting info.
Please help. :crazy:

 

If the O2 doesn't reach 600F, it isn't supposed to send any mV signal to the ECM. However, I have noticed that while the engine is in open loop during its warm-up period that my DIACOM program continues to record O2 values that slowly ocillate within a narrow 5 mV range until the system goes into closed loop. Of course, I need to point out that I have stock exhausts and the O2 sensor cannot avoid being heated as soon as the engine is running.

You didn't say whether or not you observed that the engine was running in closed loop with your DIACOM. I'm guessing that it was. If so, your O2 sensor is shot and should be replaced. Normally my '89's O2 sensor varies between 137 and 892 mV. You should be seeing a much greater variation in your O2 readings.

Check out the Tech section on the Forum. There is a Tech tip on how to wire a heater O2 sensor. The new O2 sensor should solve your problem and having a heated sensor doesn't hurt either.

Hope this helps!

 

What's the difference between a wideband and the reg O2 sensor? Why is it prefered?

 

I noticed in your sig you have headers and my guess id your O2 sensor is located on the colector and is proably not getting hot enough as you indicated. To resolve this you can get a heated O2 sensor you need to maintain at least 600 degres to stay in close loop properly and you may be swithing between open and closed loop I forgot to check but if you have a prety free flowing exhaust and headers you relay mite want to think about going to the Heated sensor.

 

You dont need a wide band sensor. A wide band sensor is very expensive and is used to fine tune you A/F ratio. The above post has a good point. You may have to go to a heated sensor. I went with the heated sensor on mine to be on the safe side.

This link will explain the wide band/O2 sensor better than i did
http://www.sficc.net/features/feature4.html

 

Thanks guys! Guess I'll be installing the heated O2 over the weekend. :thumbs:

 

There is a great tech on heated O2 sensor with part #'s.