Thread: Calling all Fuel Injection Experts!! D2A V8 O2 Sensors

Make a test rig with a spare O2 sensor, see that the 14V heater voltage is present at the sensor with it plugged in and drawing current. Your adaptor cable may have a dodgy joint. They should never be soldered. I use special small uninsulated crimps then heat shrink the joints.

I know it is pretty basic, but have you checked the continuity of the circuit between the ECU and the LH O2 sensor.
I take it you have crimped the leads if they are Falcon O2 sensors as the stainless stuff is hard to solder.
So my advice is to just check the continuity.
The other possibility is that the earth return for the O2 sensor is poor on the left bank. If they are 2 wire sensors the earth return is via the exhaust pipe presumable to the head . This may be poor on the LH bank so maybe run an earth wire from the manifold to the head.
Regards Philip A

Originally Posted by bee utey

Make a test rig with a spare O2 sensor, see that the 14V heater voltage is present at the sensor with it plugged in and drawing current. Your adaptor cable may have a dodgy joint. They should never be soldered. I use special small uninsulated crimps then heat shrink the joints.

I purchased a tail from the AU falcon harness with the sensors. This means the wires are solderable which I have done. There is no cutting into the original sensor harness as it plugs into the new AU style plug. In saying this, I will check it at the sensor itself like you say.
The fact that the sensor registers a voltage soon after starting indicates that the heater is working, but seems to want to log a fault.. Just like if the sensor is returning a voltage that varies between .45 and .69 volts, there must be some sort of signal returning from the sensor... It just won't register it and make the fuel changes..

Originally Posted by PhilipA

I know it is pretty basic, but have you checked the continuity of the circuit between the ECU and the LH O2 sensor.
I take it you have crimped the leads if they are Falcon O2 sensors as the stainless stuff is hard to solder.
So my advice is to just check the continuity.
The other possibility is that the earth return for the O2 sensor is poor on the left bank. If they are 2 wire sensors the earth return is via the exhaust pipe presumable to the head . This may be poor on the LH bank so maybe run an earth wire from the manifold to the head.
Regards Philip A

The wires were soldered into a replacement AU harness tail. The sensor wires themselves have not been cut and are in their original connector. I have checked continuity from the new plug, to the ECU plug. All good and wired correctly.

They are a 4 wire sensor so the earth is through the wiring harness. This has been checked for continuity to the ECU plug as well. I have the black wire from the sensor attached to the signal wire to the ECU (blue or orange depending on which side) and the grey wire attached to the red/black earth wire. Is there a way of testing the earth into the ECU? I have checked the continuity but only to the plug into the ECU

Its generally considered bad practice to solder o2 sensor connections.
I would buy new ones with the connector attached if I were you. I got mine from Amazon for $45 each.

Your symptom of one bank showing no activity is exactly what I struck with mine.

I had;
P1000 = LAMBDA SENSOR UPSTREAM
CATALYST BANK 2 DRIVE CYCLE C
OCCURED 7 TIMES
SIGNAL INVALID
FAULT IS CURRENTLY PRESENT
FAULT DETERMINED AS INTERMITTENT
FAULT DOES NOT CAUSE THE
MIL LAMP ACTIVATION

---
P0175 = MIXTURE ADAPTION FACTOR
FRA BANK 2 DRIVE CYCLE C
OCCURED 1 TIMES
SIGNAL TOO HIGH
FAULT IS CURRENTLY PRESENT
FAULT DETERMINED AS PERSISTENT
FAULT DOES NOT CAUSE THE
MIL LAMP ACTIVATION

I replaced o2 sensors, MAF, checked wiring etc.
It turned out to be caused by an air leak at the inlet manifold joint, probably injector o-rings too.
Sorted all that, no more issues.

Originally Posted by ashhhhh

Its generally considered bad practice to solder o2 sensor connections.
I would buy new ones with the connector attached if I were you. I got mine from Amazon for $45 each.

Your symptom of one bank showing no activity is exactly what I struck with mine.

I had;
P1000 = LAMBDA SENSOR UPSTREAM
CATALYST BANK 2 DRIVE CYCLE C
OCCURED 7 TIMES
SIGNAL INVALID
FAULT IS CURRENTLY PRESENT
FAULT DETERMINED AS INTERMITTENT
FAULT DOES NOT CAUSE THE
MIL LAMP ACTIVATION

---
P0175 = MIXTURE ADAPTION FACTOR
FRA BANK 2 DRIVE CYCLE C
OCCURED 1 TIMES
SIGNAL TOO HIGH
FAULT IS CURRENTLY PRESENT
FAULT DETERMINED AS PERSISTENT
FAULT DOES NOT CAUSE THE
MIL LAMP ACTIVATION

I replaced o2 sensors, MAF, checked wiring etc.
It turned out to be caused by an air leak at the inlet manifold joint, probably injector o-rings too.
Sorted all that, no more issues.

When this happened to you Ashhhhh, was it reading a voltage like mine? or was it either to high or too low? the thing that confuses me is if it is an air leak or similar, wouldn't the voltage be reading right down low indicating its too lean on that bank?? Mine is varying between .45 and .69 V

Originally Posted by ashhhhh

Its generally considered bad practice to solder o2 sensor connections.

PS, I have only soldered the AU plugs into the land rover engine harness. All wiring for o2 sensors has not been touched from new, as in they came with AU plugs installed.

I dont recall actual voltages but the symptom was that one bank fluctuated a lot and the other was very low and basically static. (like 0.15 low)

So yeah, your right - lean in my case.

Do you have any P codes to go with those descriptions?