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

Originally Posted by PhilipA

I wonder if it is one or more crook injectors.
Regards Philip A

This is what I was thinking when I checked the spark plugs. I would presume a crook injector would mean unburnt fuel, giving the slightly rich reading, but all spark plugs looked dry and a nice burnt grey colour. Maybe I should change injectors from side to side and see what happens...

Originally Posted by jskerm

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.

Ah, yes, I'd assumed that you soldered the AU harness plugs to some chopped off D2 sensor connectors. I made (crimped) adaptors this way so the OEM D2 wiring remained untouched and could use stock O2 sensors at any stage in the future.

Anyway, if the heater current is insufficient to bring the sensor up to operating temps quick smart, the sensor will output but at a lower voltage than optimal. A too cool sensor may also get some voltage leak across from the heater winding, old sensors can get quite bad in this respect. Moisture from the initial fuel burn may condense inside the sensor until it gets up to the correct temp. In the meanwhile the ECU has logged a fault and disregards the sensor.

So I got the missus to drive the car into town today. 120 km round trip. I cleared all codes before she left and reset the adaptations. Upon her return she said it ran very well...

It had re logged the signal missing fault for the LH bank, but also a o2 sensor heater minimum value not reached fault for both sides.......

In the live data the RH bank was still operating perfectly, whilst the other side just sat at .475 V.

Does anyone know a way I can test the earth for the heater circuit and sensor output earth? These are earthed in the ecm but does that mean they are also earthed to the vehicle chassis. Just wondering whether I can check continuity between the chassis and the earth wires at the sensor to prove earth side is ok.

It boggles me to think that it might be a vaccuum leak or injector, as it is reading too rich when it does change. It just won't "flip flop" like it should.

Seems you can get into a low km GX 200 series for around 40K now....

Yeah I think you're into something with the ground theory, 0.45 (or so) is the "cross over" point between rich and lean, and also the default state in the case of signal or earth failure.

Can't help much locating the correct earth, maybe RAVE will help?

Victory!
Wasn't an obvious one though. Checked the earth from the left hand sensor and found it was grounded to the chassis. Checked the RH one and no earth. Checked the wire right back to the ecu and still no earth. The pin for the rh earth in the ecu was grounded, the left one not grounded.
After pulling the Ecu apart and following that circuit i found a point where the ground came back again on the circuit board, luckily it was near a solder joint, put a dab of solder on it and bingo, earth back at the pin.
Anyway, after putting it all back together both sensors now work beautifully.

Goes to show theres always a solution to every problem, and if anyone is in the market for two perfectly good o2 sensors that i thought were stuffed, give me a pm!

Thanks everyone for your help.

Good news!

For those that are interested, repairing the o2 sensors has given me an extra 100 km per tank. Worth the hassle.

Well done.

What sort of mileage are you getting?