O2 sensor testing... AGAIN! (1 Viewer)

[pie eater]

Hi guys, looking for a bit of advice on a 1996 1FZ, uk spec so no OBD. I am experiencing high fuel consumption and have been looking at testing my oxygen sensor. The car has only one pre cat sensor. From the manual it says check at the diagnostics plug. My first question is the link it says to put between TE1 and E1, is this just a short, or is it something else. The manual refers to a part with a Toyota part number. I have measured the voltage between the signal wire and earth directly at the sensor and get switching between 0.2 and 0.8 volts which I think is out of spec, but I want to measure it at VF1 and E1 at the diagnostics plug.

Furthermore I have read that engine coolant sensors can be the problem. If this was the case, would the temperature gauge still work? (mine does). Also, how do I know that the fuelling system is operating in closed loop and not open loop?

Any help would be most appreciated.

Dave

 

[thestunts]

Here is a pic of the "short" locations. Use a paperclip. Then put key in ignition and turn to on, but do NOT turn on. Then count the CEL blinks.

Trouble Codes
OBD1 Codes

1 Normal Condition.
2 Air Flow Meter signal.
3 Ignition signal.
4 Engine Coolant Temperature Sensor signal.
5 Oxygen Sensor.
6 RPM signal (Crank Angle Pulse).
7 Throttle Position Sensor signal.
8 Intake Air Temperature Sensor signal.
9 Vehicle Speed Sensor signal.
10 Starter signal.
11 Switch signal.
11 ECU/ECM.
12 Knock Control Sensor signal.
12 RPM signal.
13 Knock Control CPU (ECM).
13 RPM signal.
14 Turbocharger Pressure.
14 Ignition signal.
21 Oxygen Sensor.
22 Engine Coolant Temperature Sensor signal.
23 Intake Air Temperature Sensor signal.
24 Intake Air Temperature Sensor signal.
25 Air-Fuel Ratio Lean.
26 Air-Fuel Ratio Rich.
27 Sub Oxygen Sensor signal.
28 No. 2 Oxygen Sensor signal.
31 Air Flow Meter signal (Vacuum Sensor signal).
32 Air Flow Meter signal.
34 Turbocharger Pressure signal.
35 Turbocharger Pressure Sensor signal.
35 HAC Sensor signal.
41 Throttle Position Sensor signal.
42 Vehicle Speed Sensor signal.
43 Starter signal.
51 Switch signal.
52 Knock Sensor signal.
53 Knock Sensor signal.
54 Inter-cooler ECM signal.
71 EGR System.
72 Fuel Cut Solenoid signal.
78 Fuel Pump Control signal.
81 TCM Communication.
83 TCM Communication.
84 TCM Communication.
85 TCM Communication.

 

[pie eater]

Great, thanks for that. I'll give it a try and see what happens!

 

[pie eater]

Ok checked obd using paper clip method and got continual flashing. I assume this is no code. I checked the voltage between VF1 and battery negative and got 2.2V constantly at all rpm. How can this be? Is this indicative of a wiring problem somewhere? Still reading good voltage and correct fluctuation directly at the sensor. I assume VF1 is directly representative of the voltage feedback from the sensor?

 

[pie eater]

Measured voltage at OX1 at diagnostics plug, and that follows the output from the O2 sensor. VF1 voltage sits constant at 2.2V. According to the test procedure a constant voltage is a failed sensor, yet it is cycling correctly?

 

[Eicca]

Measured voltage at OX1 at diagnostics plug, and that follows the output from the O2 sensor. VF1 voltage sits constant at 2.2V. According to the test procedure a constant voltage is a failed sensor, yet it is cycling correctly?

Did you rev the engine up to 2,500 and test there as well? Voltage from the O2 sensors should go up with engine revs if they're working correctly.

If this 2.2v is constant across the tach, then yup, time to replace them sensors. They're not completely dead yet but definitely getting there and hurting your gas mileage along the way.

 

[pie eater]

Yeah Taylor. Think its time for a new sensor. I've heard oem only for these, not cheap then!

 

[Eicca]

Yeah Taylor. Think its time for a new sensor. I've heard oem only for these, not cheap then!

Ehhhh... I went with Densos... Got them from sparkplugs.com for $150 for both... They've been working fine for almost a year, but we'll see...

 

[landboozer1]

Here is a pic of the "short" locations. Use a paperclip. Then put key in ignition and turn to on, but do NOT turn on. Then count the CEL blinks.

Trouble Codes
OBD1 Codes

1 Normal Condition.
2 Air Flow Meter signal.
3 Ignition signal.
4 Engine Coolant Temperature Sensor signal.
5 Oxygen Sensor.
6 RPM signal (Crank Angle Pulse).
7 Throttle Position Sensor signal.
8 Intake Air Temperature Sensor signal.
9 Vehicle Speed Sensor signal.
10 Starter signal.
11 Switch signal.
11 ECU/ECM.
12 Knock Control Sensor signal.
12 RPM signal.
13 Knock Control CPU (ECM).
13 RPM signal.
14 Turbocharger Pressure.
14 Ignition signal.
21 Oxygen Sensor.
22 Engine Coolant Temperature Sensor signal.
23 Intake Air Temperature Sensor signal.
24 Intake Air Temperature Sensor signal.
25 Air-Fuel Ratio Lean.
26 Air-Fuel Ratio Rich.
27 Sub Oxygen Sensor signal.
28 No. 2 Oxygen Sensor signal.
31 Air Flow Meter signal (Vacuum Sensor signal).
32 Air Flow Meter signal.
34 Turbocharger Pressure signal.
35 Turbocharger Pressure Sensor signal.
35 HAC Sensor signal.
41 Throttle Position Sensor signal.
42 Vehicle Speed Sensor signal.
43 Starter signal.
51 Switch signal.
52 Knock Sensor signal.
53 Knock Sensor signal.
54 Inter-cooler ECM signal.
71 EGR System.
72 Fuel Cut Solenoid signal.
78 Fuel Pump Control signal.
81 TCM Communication.
83 TCM Communication.
84 TCM Communication.
85 TCM Communication.

^^^^^^^^^^ So i have read numerous times on this form to not turn your car on when one has shorted TE1-E1. Why is it so import to not do this? I ask bec this seems conflicting with what the FSM I have for my 1994 FZJ80 (with 2 o2 sensors pre cat) says when checking the O2 sensor voltages. (i would post pics but cant yet im new to the form!)

basically under the heated o2 sensor section the manual says

(1) disconnect o2 sensors and check resistance is ~5ohms
(2) warm up engine to normal operating temp
(3) monitor feedback voltages with a voltmeter on the diagnostic plug between terminals VF1-E1 and VF2-E1 and perform tests:
-warm up o2 sensors with engine at 2500rpm for 2min.
-using sst 09843-18020 (paper clip) connect terminals TE1-E1
-Monitor voltmeter fluctuations in 10 seconds -> 8 or more is normal
-lots more steps if its less than 8 fluctuations or 0 times (ill post picture latter)

Any thoughts about this? sst 09843-18020 is just a wire right?