Bank X running rich

[AlphaCrow]

Hi all!

2015 Ram, 1500, v6 3.8L, 2wd, Lonestar pkg.

About 4 months ago, had a misfire code at about 100k miles on car, so I changed spark plugs, coil packs, and fuel injectors, and did my best to clean it up in there.

A little over a month ago, I started getting "Bank 1" running rich code. I'd clear it and then later get a "Bank 3" running rich. I keep getting the codes, alternating between different banks (1 and 3 is all I've noticed).

Took it to dealer to diagnose, came back as Engine Coolant Temp Sensor being bad and causing injectors to be rich. I changed out the sensor.

Codes clear for a few days, then the "running rich in Bank (1 or 3)" is back again.

I'm at a loss! If it was consistent, I'd say a bad injector that needs replacing, but with the change... I just don't know what is the next step. Could it be the thermostat valve? I read somewhere that this part goes out and causes temp problems that then cause idling issues.

For the record, the code "running rich in bank X" comes up within a minute of starting up. Once in a while, it will clear itself but then come back.

I'd appreciate any help! The dealership was adamant that only the ECT sensor was the problem, but now I'll have to take it back to them in exchange for my life savings, lol. (P.S. they wanted $550 to change the ECT sensor).

[Stealthee]

It definitely sounds like an ECT. Did you change the right sensor? There are usually two. One for the gauge and one for the ECU.

If you did change the right one, depending on what brand you used you could have gotten a dud.

[AlphaCrow]

Well... I'm not sure where the other sensor is, lol. I looked up the sensor that is on the engine block near the rear, driver side cylinder.

I also changed the thermostat, but that did not fix the problem either.


So after changing the sensors and thermostat, I've noticed that I get no code until I drive for a while and then sit idling (fast-food drive thru, etc.).

It could be a bad new sensor, but I wonder if there isn't another more likely cause. I'll try to get the old sensor out of the garbage and check it with a multimeter to see if it was functioning correctly, perhaps its a wiring issue.

If not, I may have to pay the dealership again and probably get told the same thing again.