1999 dodge ram1500 engine o2 sensor runs better unplugged

[workky]

I can’t remember the codes it pulled, but all are 02 sensor codes. Runs ok when cold, starts running like crap when it warms up. Spark plugs are gas fouled. It cuts out, coughs through intake, you have to press the gas petal repeatedly to clear it up, comes back at extended idle periods.

Unplugging the O2 sensor resolves all of this. I believe the 02 sensor is bad, and have new one on the way, but I just replaced it last year.

Is there anything that can make the upstream 02 sensor go bad prematurely? My concern is plenum gasket, can it do this if it’s bad?

My truck is a ****, the winch cost more than the truck. However, my girls and GF love riding through the woods in it. I keep it alive, it has 267,000 miles on it. It is a woods truck, mud truck ,and has survived 3 years of abuse. I’ve never owned a dodge truck, never really liked them. However this thing is tough as nails, I’m impressed.

First time poster, but have been here reading lots

Thanks

 

[Mister Luck]

It could be timing chain when cold, expands when engine temperature rises or an engine temp sensor is not functioning properly, what type of coolant thermostat does the the truck have ?

Edit:
coolant leaked into the exhaust flow will kill an 02

 

[Mister Luck]

I believe your truck also uses a MAF sensor which if malfunctioning could be upsetting the fuel metering of closed loop operations.

 

[dapepper9]

I believe your truck also uses a MAF sensor which if malfunctioning could be upsetting the fuel metering of closed loop operations.

In short, no. MAP based.

Plenum burns oil and oil kills 02s. Not at all outside of the norm. On my build I run a header evac crankcase ventilation setup (not exactly emissions compliant) but it exits right behind the upstream sensor so I placed my wideband on the driver side collector to keep it away from all that. General recommendation is NTK sensors.

 

[Mister Luck]

In short, no. MAP based.

Plenum burns oil and oil kills 02s. Not at all outside of the norm. On my build I run a header evac crankcase ventilation setup (not exactly emissions compliant) but it exits right behind the upstream sensor so I placed my wideband on the driver side collector to keep it away from all that. General recommendation is NTK sensors.

So 2004 is the change over year I wasn’t sure about that

That’s the fix your going with?
A wideband is necessary with an exhaust vent pipe for blow-by?
Are you using a Krank Vent ?
There are potted O2 sensors that simulate the signal if you kill enough sensors it would probably end up paying for itself .

 

[dapepper9]

So 2004 is the change over year I wasn’t sure about that

That’s the fix your going with?
A wideband is necessary with an exhaust vent pipe for blow-by?
Are you using a Krank Vent ?
There are potted O2 sensors that simulate the signal if you kill enough sensors it would probably end up paying for itself .

No, at least not for trucks. They’re MAP even to this day.

What do you mean fix? A wideband is required for custom tuning which is why I only mentioned it in reference to my build. My PCV valve no longer exists. In its place is an old school header evac system, a hose from the valve cover to the header collector to suck out crankcase gases. It goes to the passenger side collector so I placed the wideband in the driverside to keep it from getting any oil mist on it.

The OP needs to just weld in new bungs on the replacement pipe and screw em in like they would normally be. These trucks are pretty dumb

 

[Mister Luck]

Sorry I thought you were answering fir the OP
I’ve seen other chrysler products in the past have the 2004 as the change over year man thats was messed up when the trucks have had MAP’s this whole time that was a big contension on drivability

if your welding bungs and plugs to tune why not just use a sniffer clip on the tail pipe for tuning ?
oh I see your not using a dyno …

but if the OP has that much blow by maybe he’s got other problems (thanks for the tip on the oil intrusion) I thought oil wouldn’t kill a 02 outright just foul them and the shield cleaning them would put them back in business ???

 

[dapepper9]

Sorry I thought you were answering fir the OP
I’ve seen other chrysler products in the past have the 2004 as the change over year man thats was messed up when the trucks have had MAP’s this whole time that was a big contension on drivability

if your welding bungs and plugs to tune why not just use a sniffer clip on the tail pipe for tuning ?
oh I see your not using a dyno …

but if the OP has that much blow by maybe he’s got other problems (thanks for the tip on the oil intrusion) I thought oil wouldn’t kill a 02 outright just foul them and the shield cleaning them would put them back in business ???

Nothing wrong with speed density, it’s widely used and no it doesn’t have drivability issues.

There’s nothing wrong with email tuning. In fact the vast majority of dyno shops can’t tune nearly as well as email tuners. They can do it quicker because there’s no delay from waiting for emails but that’s about it. Sniffers also aren’t nearly as accurate as a collector 02 and the wideband is something I can monitor when I’m driving it if there’s an issue. It’s not 2003 anymore

Read up on the plenum issue, it’s not blow-by.

 

[Mister Luck]

I think you might have mis-understood me I never said there was a problem with speed density.
It sounds like I need to read up on email tuning.
Depending on what type of rings you are using their tolerances the cylinder finish,
I wouldn’t be ok with oil flushing my exhaust, a rich fuel mixture is OK,… oil not that much.

 

[dapepper9]

I think you might have mis-understood me I never said there was a problem with speed density.
It sounds like I need to read up on email tuning.
Depending on what type of rings you are using their tolerances the cylinder finish,
I wouldn’t be ok with oil flushing my exhaust, a rich fuel mixture is OK,… oil not that much.

It’s. Not. Blow-by. Read up on the plenum gasket. It’s a thing specific to these that happens to ALL of them. I’m not sure why you keep coming back to blow-by when I’ve been very specific that it’s not blow-by.

 

[Mister Luck]

is it fixed by replacing the gaskets ?
or once you replaced them they immediately leak again ?
is there one brand of gaskets… or are there other gasket manufacturers that make them ?

 

[dapepper9]

is it fixed by replacing the gaskets ?
or once you replaced them they immediately leak again ?
is there one brand of gaskets… or are there other gasket manufacturers that make them ?

Stock gasket is crap. Dodge and Felpro both came out with updated gaskets that are steel core rather than felt. Many claim it’s a metallurgical thing but it’s just a poor gasket that swells with lifter valley oil