And all the possible sources for over fueling are?
 

I'm still trying to track down my over-fueling issue. Some quick background info for anyone that wants to go beyond my question and solve my issue.

-i've got codes: P0134 & P0154 (front o2's "no activity")
-i'm getting between 6-8 mpg, and you can smell the raw fuel when the truck is running
-i've gone through 3 new sets of front o2 sensors from AB
-i've had this overfueling issue before and after I got new universal cats installed
-i've watched the latest new set of front o2's function properly upon install with live data. Then days later the familiar 0134 and 0154 (no activity) codes for both front o2's and rich rich fuel smell back again.
-i've heard the ECU controls the heater element and CAN be malfunctioning and leaving the heater element on until burnt out
-i've heard from numerous LR tech's and master tech's and indy shops that they've never seen the ECU been the problem, and have only replaced a handful and all of those were for security system reasons
-i've heard a little oil or coolant in the connector can kill the sensor
-i've thoroughly cleaned out the connectors before installing the latest set
-i've heard that the ground wire behind the engine (or in back of) is often the cause for a "bad" o2 sensor, but rarely for both front o2's at the same time
-i've heard many that have had issues with AB's o2 sensors
-I have a hard time believing 3 sets (6 new sensors) were all bad after short use
-i've confirmed that the sensors are receiving power properly
-i've confirmed that the other 3 wires between the connectors and the ECM have continuity and function properly

I'm hoping to get the truck hooked up to a Testbook (or equivalent) this next week and see what all is going on and what's the source of my frustration.
However, I'd like to test and check as many things as I can myself, first.

So, please help guide me with checking any and every possible cause for over-fueling or killing o2 sensors.

Thanks, DIIB

So, how do you know you are over fueling, what code numbers are you getting, have you confirmed with a scanner that you are in closed loop and how many miles on your truck?

Codes: P0134, P0154 (bank1 sensor 1 no activity, bank 2 sensor 1 no activity)

How do I know I am over fueling: 6-8 mpg's and you can smell the rich raw fuel when running, or just driving with the windows down and coming to a stop.

Question 3: Yes, and no. I used a live data scanner to confirm that the new front o2 sensors were functioning properly and that the truck would go into closed loop after warmed up. Watched it do this twice. A matter of a day or two later, the 2 codes are back and the truck is in the default setting and staying in open loop.

I'm trying to figure out my chicken or the egg conundrum: are my O2 sensor heater elements getting fried and then leaving the truck in open loop and over fueling so much. Or is something else over fueling the truck which then kills my sensor and leaves it in open loop.

Is there any chance that you have leaky injectors, dumping too much fuel? Before you get the no activity codes, do you ever get any other codes, like for too rich?

No other codes for the last several months. Bought the truck and had 13 codes at one point, most of them taken care of with head gasket job and MAF sensor.
But to answer your question, sure, I'm sure I could have leaky injectors. I don't know how to check those. But will check fuel pressure asap.

Other recent work done for reference: (within last year)
all gaskets and seals except for crank seals and oil pan gasket
green coolant swapped in
new pulleys and serp belt
major service done except brake fluid
new bosch+4 plugs
new magnecor 8mm's
newer style upper radiator hose
new alt (reman) from Advance auto
new battery
new t-stat from AB
new gaskets for both ends of manifolds
new universal cats
new central muffler
new o2 sensors (all four) from AB
new MAF sensor Bosch from BPofUtah

So it would be nice to get this thing running properly to say the least.

I 2nd the check for leaky injectors - one of mine failed open, and I saw the o2 inactive codes. (as well as smelling the rich running)

My quick check was to check fuel pressure - it went down to nothing almost immediately after shutting the engine off (I just pushed on the schraeder valve to release pressure).

Matt

You list mentioned a new MAF sensor. Did you get the Bosch/LR one, or aftermarket?

Try putting less gas in it next time. :cool: HA!

That is a mighty extensive (or do I mean expensive??) list you have thar Florida Boy! Two things fer ya ta konsider...

Have you considered that the fuel pressure regulator back at the fuel pump is DOA? leaky injectors are a strong candidate too.

Lose the Bosch +4's ... what do they look like? sooty, wet, ...?

hey, who let you out of the D1 or RRC sections? I got a case of your snooty beer that says you can't come over and fix it!

Beer on Sucka!... I may have time this weekend... Sun is out with Easter and all but Sat might be cool? If you drag that "Disco" with no swivel balls up to my part of our little sandbar I'll let you drive the Series around the golf course again! :D Shoot... I'll even set up the tent in the front drive soz you don't get sunburnt.

And by the way, ain't nothin' snooty about anything coming out of Comstock, Michigan. (Right Spike) Just Damn good brew.

:cool: