Agreed unlkely on the MAF, but it is easy to change...

 

I did some research and tried to educate myself on the short term and long term fuel trims.

Then I did a test drive. I changed my ODBII scan tool to get long term also now

After the engine was at operating temperature this is what I got.

Bank 1
Voltage range from .775 to .820. (does not oscillate like bank 2)
Voltage before shutting down engine .805
STFT range -25% to 0.0%
STFT reading before shutting down engine 0.0%
LTFT range -10.9% to -10.9%
LTFT before shutting off engine -10.9%

Bank 2
Voltage range .055 to .830
Voltage reading before shutting off engine .075
STFT range -7.0% to 14.1%
STFT reading before shutting down engine -2.3%
LTFT range 2.3% to 15.6%
LTFT range reading before shutting down engine 3.9%


So if my understanding is correct Bank 1 is running rich. And the computer has compensated for the new normal to be -10.9%. But this does not allow the voltage reading to oscillate in as big as range and then it is throwing the stoichiometric ratio off.

Since it is a negative number it seems there is not a vacuum leak nor a leak in the exhaust before the O2 sensor.

Could be leaky injector. Any other ideas what it could be.

Not to just throw money and parts at a problem but I could get 4 new injectors for about $200 from Island 4x4. In the grand scheme $200 to compete the fix is not too bad.

Thanks again for the help,

Thoughts...

 

I took out the left bank spark plugs today.

1,3 and 7 all have the same look.

5 looks different than the others.

 

Have you checked anything else ? Like smoke test on intake and exhaust ? Have you tried plugging your purge valve at intake ? Like I suggested
when I had these issues my o2 readings were all over the place until I fixed the cause and the symptoms went away.

 

Looks like Cyl #5 is rich. Yes you are correct regarding the fuel trims. Let's recap just to be sure we understand,swapping sensors left to right, the problem does not follow the sensor. You are not getting a misfire code, only an oxygen sensor code.

Increasingly looking like a leaking injector in cyl number 5, you could easily pop the upper intake off and move that injector to the other bank for a test.

 

Redwhitecat, no I have not done a smoke test yet. I'm thinking because the long term fuel trim is negative and only one bank is affected it is not a vacuum leak. I did see your post when you had a similar issue. I did pinch close the purge valve intake. The engine did not like this at all. After a couple of miles I had to pull over and un-pinch it. Engine was running very rough and threw some mis-fire codes.

Extinct,

Yes swapping sensors did not do anything and issue did not follow sensors.

I do have 2 O2 sensor wire extenders. I have used one at a time to plug the left bank sensor into the right bank wiring and the opposite but I never did it with both and ran the engine. When I did this the bad reading would follow the wiring not the O2 sensor.

I like the idea of a leaky injector. Seems this issue would make sense of when I swapped the input wires to the ECU.

I'm thinking about just replacing the fuel injector for cylinder 5 vs. swapping one from another cylinder based on the time and effort it takes to get all the way to pulling the rail line. I'd rather risk spending $60 from Island 4x4 and install a new one and after everything is back together the job would be done.

I also like the idea that maybe my original issue was a leaky injector and I misdiagnosed the code to a bad O2 sensor and then my O2 sensor wires broke and after replacing the wire harness I'm still getting the original code.

 

I have pulled the injectors and cranked engine while watching injectors to diagnose spray. You may be able to see the leaking injector if you jumper the fuel pump relay so that it runs continuously.

 

And the winner is........bad ECU

So to review this entire work.

Purchased the D2 from a salvage auction. For this reason I never had any historical knowledge.

Upon putting in a new battery I got 2 codes.
Misfire cylinder #4
P0130 Left Front bank stoichiometric ratio out of operating band


New spark plug for cylinder #4 solved the misfire issue

Tried a new O2 sensor but that did not work and afterward was getting P0134 (open circuit)

That is when I noticed the wires had broken off at the connection for the O2 sensor.

Replaced the engine wiring harness (quick tip here, if you need to do it check the product number on the white tag where one of the connections plugs into the ECU. There are multiple versions)

Afterward I started getting P0134

The long term trim on left was showing rich so I replaced the fuel injector on #5 and spark plug due to the spark plug having a much different look compared to the other spark plugs on that side of the engine. (interesting thing here was there was no O-ring on the top of that fuel injector. I had the fuel rail lifted enough so I could see where it seats and there was no O-Ring)

Put everything back together and now I was getting code P0132

This is when I changed the ECU with a matching BCU

Turned the engine on and for the first time I was seeing voltage readings that oscillate on bank 1 sensor 1.

I now have 100 miles on it so I'm feeling good about this fix.

Interesting note for the conspiracy theory of Oxygen sensors and which ones are best. Although my ECU was broken and not reading the voltage correctly. The Original that I had moved over from the right bank for trial and a new Bosch sensor gave similar readings but were different from the new Walker sensor I purchased. The Walker sensor always showed a higher voltage reading.

I ended up using the Bosch.

Now I have the 3 Amigos, so now it's on to that project with Option B.


Hope this summery may help someone else in the future.

 

I have been fighting with this same issue... except that 5 new sensors all show zero volts (3 Walkers and 2 Bosch). With all your troubles did you ever have that? I am currently working on checking continuity. I am getting the correct readings on the correct pins at the connector while its running. Do you have any tips? This is driving me insane.

 

Replacement engine ECU solved my issue.

I was unable to synch the replacement engine ECU with my BCU using a Nanocom. I ended up using a paired BCU and ECU from a salvage yard and then turning off the blinking milage on the instrument panel with the Nanocom. This was the actual milage of the vehicle shows on the instrument panel regardless what the milage was on the BCU out of the salvage yard