Germansheperd

Guess I dont understand why you would wire in heated O2’s when the car calls for the basic 1 wire O2 you can get for $12 new on Rock Auto?

Injuneer

With headers, the unheated O2 sensors may not stay hot enough to keep the ECM in closed loop. Very common for 93 owners to make that conversion. From his earlier post, regarding my review of his Scan9495 data log, neither of his O2 sensors were working. He then found out the engine had headers (apparently wasn’t aware of this ‘till he started looking for the O2 sensors), so decided to do the heated O2 sensor conversion.

Unfortunately his earlier posts were tacked on to the multi-page Scan9495 thread, and I just haven't had a chance the move them to a new thread. Now I will, and as a result they will be inserted at the beginning of this thread, probably adding a bit more confusion.

teddie300c

I ordered Bosch 15703 O2 sensors. They would only let me order 1 so I had to have someone get me the other so I got them on separate days. The first one I installed on the driver's side. It's a 4 wire sensor and there are 2 white wires, and a grey and black. I used the two white wires for the heater wires and the black for the signal. I looked this up on Google and it said the grey is a ground so I connected it to ground also. I remember the first read 1.097v but I'll have to scan again for the second. It didn't run bad till I installed the second sensor which I installed the same. I also clipped the grey wires after to see if it would change cuz the shoebox link said it was unused.
Also it through a code for bank 1 O2 sensor lean or something

teddie300c

So the code I was getting was 44. Bank 2 starts out at 1.097 and bank 1 fluctuates in the .900's and eventually works up to 1.097. It then hit closed loop sometime after and starts sputtering.

teddie300c

heres the last scan

Germansheperd

Cancel that order. Bosch are the absolute worst. AC Delco, NGK/NTK, or Denso (AC Delco are repackaged NTK or Denso).

Injuneer

AC Delco O2 sensors are recommended. Many people complain about the Bosch sensors with the LT1. Do you have the wire color diagram for the Bosch sensor? Sounds right based on a typical “universal” sensor. Shoebox’s diagram indicates the signal ground (low reference does not get grounded. The sensor grounds to the pipe.

I'll try to look at the log in the morning.

Injuneer

Quick guess..... O2 sensors are shorted to 12 volts. 1.097 is probably the max scalar value based on an 8-bit field. Sure, goes into closed loop, the ECM starts cutting fuel to pull the O2 sensors down to an average value of 450 mV, but nothing happens, stays at 1.097 volts. Didn’t go all the way to the bottom, but I bet between the STFT's and LTFT's it’s pulling out at least 30% of the required fuel and it’s running extremely lean in closed loop. Explains why it runs bad in closed loop. Do not attempt to drive it in this condition.

teddie300c

So any suggestion on what I should do. I've been looking for an exact wire reference for the O2 but yet to find one. Only one starts out at 1.097v. When I put the first one on it was staying at 1.097v but when I put the unused wire to ground it fluctuates in the .800's from the little I ran it.

Injuneer

Let me look at the log in detail. The left O2 probably simply hot enough to work when you started the engine. The right side was probably slightly below the required minimum temp (~600°F) to operate, and was simply approaching full operation. When it hit the required temp it maxed out just like the other side.

If the sensing element is seeing 12 volts, it could be damaged already. But I need time to look at the log on something less awkward than my iPad.

teddie300c

So the shoebox says that what is a grey wire for the O2 is unused. Another source from Google says that this wire is ground. I hooked it up on the driver side and the reading I was getting fluctuates quite a bit like what I think it should but the passenger side drops and fluctuates but only .100 to 0

teddie300c

You think I should get different O2 sensors being how these aren't working out and have a bad rep I was unaware of. I'm going to look into contacting Bosch in the meantime.

teddie300c

Again I am really appreciative of all the help. I'm usually ok with researching and figuring stuff out but I've been really at it with this thing. So thanks again

teddie300c

Couldn't I take a meter and check the signal wire to ground and read the voltage to see if it's at 12v

Injuneer

In the data log, that is a stored code. It's present before the engine even starts. No way that code can set with the high O2 sensor readings you have. DTC 44 sets when the O2 sensor readings are stuck below 200mV for 50 seconds, and the system is on closed loop. That's something that happened with an earlier configuration of the O2 sensors.