I have an `88 Sentra; E16I dead stock. I've rebuilt the transaxle, wheel bearings, half shafts, etc, etc. I swapped the seized 240,000 mile engine with a 120,000 mile engine from a `87 wagon. Exact duplicate, cept O2 sensor . My car originally had a single wire and a smaller port in the exhaust manifold. I am using the 3 wire that came with the newer engine. I simply am using the center wire connected to the harness. The two outer heater wires are not being used. The single sensor wire doesn't fit in the newer fitting, pipe thread located in exhaust manifold.
In Mode 1, the ECM shows it’s in limp mode, or open-loop. No green LED flashing. Also, no red led glow. No lean/rich activity in Mode 2. Mode 3 shows code 55, no faults detected. At times it may show code 13, coolant temp. However it is properly grounded, ECM wire from temp. sensor shows continuity. Sensor at engine run temp shows somewhere like 172 ohms, which looks good.(It may need to be in closed-loop to address sensor inputs and show other fault codes.) There is no "Check Engine" light on dash. I've left battery disconnected for 25 hours with no change.
1] How do I pursue a fix/trouble shoot open-loop condition of the ECM?
2] Can I force a closed-loop? (to catch any other fault codes and trouble shoot the main issue denying closed-loop status.)
3] Do I need to reset a relay or the ECM to solve? How to reset?
4] Is the 3 wire O2 sensor being used properly? I know, but really? Maybe the center wire is the wrong one for the ECM input? Are the two sensors equal as far as voltage/signal generation at a given oxigen concentration sensing?
Any help will obviously be greatly appreciated. (I fear for the brick wall)
Added edits:
The thermostat was stuck full open, fixed and now heats properly.
The center wire is correct, but while running at normal hot temp, the signal from the O2 sits at 384 mV, no fluctuation, even when I forced a lean condition by pulling a vacuum hose.
Found to my delight that a new O2 sensor was only $20! Far from the ~$100 I thought it would cost.
I'll get a $13 gasket set to swap to the single wire O2 sensor and put out the $20 for a new sensor.
I'll add a further edit to update this thread. Someone in the future may find it helpful.
Do not be afraid to reply with your thought, that's why I joined this forum, for all your experience and wisdom.
Patrick
Linear Mode
