Good Morning!

I am going to drop a post on here to see if any of you folks have ideas.

I have a 2001 Dodge Ram 1500 5.9L V8 Gas. In the past I had an issue with the Engine, Intake Plenum and Wiring Harness. I ended up having to set this truck aside as a project, unfortunate. Long story short, I ended up getting free time and some disposable income to try and fix this beauty.

In the past, which i posted about on here. I had the catalytic converter get too hot when trying to take it in to a shop. I ended up straight piping it. I found time to start on it again, It ran really well, and constantly backfired out of the tailpipe. And not to long after I had an issue with the PCM, I got a new one programmed and installed (I don't remember exactly what the issue was or the testing that I did to narrow it down to the PCM, but i'm certain that I did.) When it arrived to get the PCM installed and programmed, the technician working on it said that they were unable to replicate the issue that I was having and proceeded to drive the vehicle around for 20-25 minutes and said that it ran and drove flawlessly. The night that it was released from programming, it drove home perfectly, no issues at all. The next morning, i fired it up and it ran like absolute crap. It's now back to backfiring out of the tailpipe under any kind of load, but when it idles, it does so without issue.

When i replaced the O2 Sensors, i found that there was a burnt wire, cut and recrimped it. But the truck is still throwing a code for it.

Everything that has been replaced so far:
Spark Plugs and Wires (haven't routed them per the TSB yet)
Cam Position sensor (Mopar Sensor)
Timing Chain and Gears (Double Roller as suggested by HeyYou)
Throttle Position Sensor (Mopar Sensor)
IAC Valve (Mopar Sensor)
Upstream and Downstream O2's (NTK)
Wiring Harness (OEM)
Evap Canisters (OEM)
Fuel Pump (Aftermarket from O'Reillys)

I am trying to figure out why this truck is backfiring as soon as you step on the gas but runs perfectly at idle. There is a code for an O2 sensor, I will pull it off the vehicle and throw it in the thread a little later today. I have tried to include as much information as I could. If there are any questions or tidbits of information that may be pertinent that I missed please let me know!

Thank you for the time!

 

Verify your firing order, may also wanna re-route the plug wires while you are at it.... cross talk isn't uncommon. (and is the whole reason for the TSB....)

If you have a scanner, see what fuel trims look like, and if there are any pending codes. (especially misfire codes.....)

 

Code Read by my Autel Maxi
P0132 - 1/1 O2 Sensor short to voltage

While Live Data shows 1/1 Oxygen Sensor Voltage is between 3.9 and 4 with a goal of .49.

I am not showing any pending codes.

Fuel Trim:
1/1 Short Term = 0
1/1 Long Term = 0

Other Info:
Fuel System Status - Open Loop DTC

 

Disconnect the O2 sensor. See if it runs any better.

 

O2 Sensor Disconnected, it still starts to bog around 1200 RPMs but the live data is still showing a fluctuating voltage to both O2’s…

 

Short to voltage is likely something in the wiring harness, not the O2 sensor itself. The measured voltage range makes me think there is 5V sensor supply getting into the O2 signal wires. What do the working O2 sensors read, and what intake air and engine temperature does the PCM read ?

 

You should have soldered it and used heat shrink. Water will get into crimp connectors and eventually cause issues(poor or no connection). A P0132 is a high return voltage not a short.
P0132 O2 Sensor 1/1 Circuit Voltage High
I would monitor the return voltage from start up to closed loop and see what the voltages are.

 

This morning I reset the battery. The engine coolant started at 40 degrees working up to 180 where it is now hovering.
Intake air started around the same and climbed to 125 where it is hovering.
O2 sensor 1 remained at a constant 4v the entire time.
O2 sensor 2 fluctuates between 0.04 and 0.10

 

I would have soldered it, if I had that available to me. I used a Marine grade butt connector and heat shrinked over the top of it. It was simply the best I had available.

As far as the code being for Voltage High versus low. I simply put word for word what the scanner said I apologize.

From start to closed loop:
O2 sensor 1 remained at 4V with no fluctuation.
O2 sensor 2 fluctuated between 0.04 and 0.10.

Once the engine hit 180 degrees the fuel system switched from Open Loop to Unknown and set DTC P0132 Confirmed with P0135 Pending.
O2 Sensor 1 is between 4.1 and 4.2
O2 Sensor 2 is between 0.90 and 0.95

 

O2 sensor return voltage should really be between .1, and 1 volt. You can ignore sensor 2 if you aren't getting any codes for it.

Unplug the front O2 sensor, see if the PCM still sees 4volts on the return signal. If it does, you have a short there to the 5 volt supply circuit. Need to find that, and fix it. Of course, this is the sensor where the connector is up on top of the trans...... Yeah, that was nice of Dodge.