[Big Al]

my D had both upstream & downstream O₂ sensors. 1 in the "Y" pipe and 1 after the cat.

Same here on my 98, one in the Y-pipe, one after the Cat!

Note, although mine was not sold in CA, my build sheet shows it came with the CA emissions package so I guess that's why it has two O₂ sensors instead of just one. Strange thing is, I "know" it came with the standard "Federal" PCM instead of the special CA emissions one as I had to cross reference the PCM's part number when I ordered my Mopar PPCM and it came up as the Federal model (and it's for sure had the Federal model Mopar PPCM it in for the last 6+ years with no problems!)

What's up with that??

 

[IndyDurango]

Well, a couple of interesting things I discovered today:

- this is the only DOC Forum III thread with "P0420" listed in it. P0420 = Catalyst System Efficiency Below Threshold (Bank 1.) I assume Bank1 is the O2 sensor under the hood since my '00D has two O2s, one is also back by the CAT too.

- today at nearly 166,000K my D threw her first code, P0420. Out of the blue, the engine light came on. Driveability was unaffected.

- the on off on off on off key turning works on the '00 D and shows the code in the mileage window. If you turn on and off 4 times, it doesn't work, only 3 times provides the code in the window

- the SuperChips programmer is indeed a multi-tool. It read the single code, P0420 and allowed me to clear the code right there myself. No need for needing extra time to take care of it, or a trip to the autoparts store/dealer for clearing.

- in discussing this with a DOCer this evening, seems even if things are good? we should be changing the O2 sensors at 100K I guess?!? As for me, both my O2s, the TPS & the IAC are all factory originals right out of Newark. Wooo Hoooo, I may get better MPG and HP if I change them to new! or I may foul all my stuff up! Dad always told me, "don't fix it if it ain't broke."

- Drivability is still good so thinking ahead to keep it that way, I bought a can of SeaFoam and poured it into the tank with 16 gallons of gas, 1oz to 1 gallon per the can's instructions. This too is a first for me, I have poured 1/2 a can down the TB once and thought I was killing my D :shock: I think the Sea Foam will clean out anything and I'll go back in with fresh gas and some Lucas. Plus I figured the Sea Foam to probably be just as good or better than all the other gas treatments out there. Those than know me know I've put lots-o-stuff in my fuel over the years, including a long, valuable run at Acetone. I stopped for no real reason, just got away from it.

- knocking on wood!

<u>Update</u>
Two weeks to the day and another P0420 today. Looks like a new O2 sensor is in my future this weekend. Woo Hoo! More performance with new sensors.

IndyD

 

[FSTDANGO3]

I believe you have two 0₂ sensors on that D Indy. I'd change both of them while I was under there.
Don't forget, Mike only recommends OEM replacements! :cheesy:
Steve
DOC Pres

 

[IndyDurango]

I believe you have two 0₂ sensors on that D Indy. I'd change both of them while I was under there.
Don't forget, Mike only recommends OEM replacements! :cheesy:
Steve
DOC Pres

Yes I have two sensors. I'm avoiding the rear one, it looks hard to get to, etc.

IndyD

P.S. Anyone else with suggestions on brands and sources. I know Mike, OEM and not Bosch. Anyone else?

 

[FSTDANGO3]

Cmon, you're an experienced Durango owner now. Get it done!
Steve
DOC Pres

 

[IndyDurango]

P0420 again today. Two months since the last one. I bought a new OEM one from the stealer. Changing it today :| I guess 170,000+ miles isn't so bad on the original.

IndyDurango

 

[IndyDurango]

EDIT: I went out and looked around the D and the sensor doesn't jump right out at me. I went through my archives for a photo or instruction set and have nada.

Anyone know where it is and have any supporting documentation on changing it out?

TIA!

IndyD

 

[grantos]

Aloha Indy,

Easiest way to find it. Find the catalytic converter. Now follow the exhaust upstream from there. It should be screwed into the exhaust somewhere after both the left and right banks of exhaust come together.

Likewise, look downstream of the CC and should find the downstream unit.

The way the O2 sensors are used?The PCM reads the upstream one to make adjustments to the fuel curve. Rich?lean it out. Lean, richen it (all after the engine has warmed up.) The downstream one is used by OBDII to check to make sure the CC (and I guess the upstream one) is doing its job. Essentially, the downstream's O2 signal shouldn't have any variance if the upstream components are working correctly.

Hope that helps,

aloha,
g

EDIT: I went out and looked around the D and the sensor doesn't jump right out at me. I went through my archives for a photo or instruction set and have nada.

Anyone know where it's and have any supporting documentation on changing it out?

TIA!

IndyD

 

[hlackerm]

98 has two O2's, one on the y-pipe, one on the exit side of the cat, I know because I re-did my exhaust.

Helmut

 

[IndyDurango]

P0420 again today. Two months since the last one. I bought a new OEM one from the stealer. Changing it today :| I guess 170,000+ miles isn't so bad on the original.

IndyDurango

Ditto. Same O2 sensor, never changed it. 198,000 on it now. Maybe I'll change it out on Saturday. It's been 1 yr & 9 months since the last P0420. My guess is the change in fuels from summer to winter blend and from winter to summer blend is my trigger. That and age. :cheesy:

IndyDurango

 

[FSTDANGO3]

Just get it done. Stop procrastinating, it can only help performance
Steve
DOC Pres

 

[IndyDurango]

Changed out the front O2 sensor. It was fairly easy. All in all, my son (for his smaller hands when/where needed) and I got the old one out and the new one installed in about 20 minutes.

It wasn't stuck and came right out once we could get a wrench on it. The O2 Sensor socket I bought was useless whereas there was no way to get the ratchet on the socket and then on the sensor. I could get the socket on, but that was it. I ended up using a standard wrench from a different angle and voilá! I guess 197,000 or so miles was just about enough on the original stocker.

From the looks of it, my front-of-the-cat and the behind-the-cat O2 sensors are identical. Our 20 minutes was split by figuring out how to get the large wrench in there and then chasing an invisible christmas tree hole to push the sensor's christmas tree push plug into. On the front sensor area, there doesn't appear to be one and the plug just hangs nicely in place. On the rear O2, there's a metal bracket that the push plug goes into. Had it not been for the cat and mouse time wasted, once the truck is up and in the air, the swap would have been a 5 minute task. We put the D up on all for corners to give us plenty of working room under there just in case. Worked out perfectly.

In my mind, the idle is smoother/quieter. Overhead computer says I picked up 1MPG. I cleared out the P0420 code with my Tuner and lets hope it stays gone from another 150,000+ miles. I'd be at 350,000 by then! :bugeyed:

Maybe I should swap out the TPS, IAC, MAP and rear O2?

IndyDurango

 

[Thrush]

That's funny, I bought the same O2 sensor socket and couldn't use it at all either! :lol:

I did both of mine at the same time, ~85K miles. I believe if the MAP sensor holds vacuum through a suction gun, it's still good. The IAC might be a good idea. I'm going to do mine at 100K just because it's not too spendy, and I don't know how you check it unless it failed.

If you do replace the IAC, let me know if it did anything for idle.

 

[Durangutan]

It wasn't stuck and came right out once we could get a wrench on it.

IndyDurango

With the exhaust hot or not? I've heard you need to have the exhaust nice and hot to aid in releasing the sensor from its' port. On the Festiva it was really very accessible (right in front of the transverse-mounted engine), yet I still needed to heat it up before removal and use a jack handle for additional leverage to break it loose.

The pre-cat sensor and the transmission filter/band adjustment is all I have left to do on D'tan. I hope we have better weather this weekend. I intended to do it yesterday but we got cold weather and 3" of snow in Foristell so laying under the D was the last thing I wanted to do.

OBTW I picked up 2 MPG according to the overhead console thingy since I replaced the belly pan and the broken intake bolt, plus cleaned the TB and the assorted attachments. Last time I was driving it regularly I was seeing 12.5; last two tankfuls have yielded 14.5. Hopefully the O2 sensor will kick in another one.

 

[IndyDurango]

Thrush, will do.

Dtan, cold. It was easy. In fact, I got less than a full turn of the wrench and took it off the rest of the way by hand.

IndyD

 

[IndyDurango]

Another P0420 today. Must be the rear one.

I also had a P1281 soft code (P1281 Engine is Cold Too Long.) With my malfunctioning FAL VSC, and 20 degrees outside? go figure. Rarely heats up and was built to run cool? just not that cool. :wall:

Driveability was unaffected. Cleared the codes with my tuner in 60 seconds and now back to driving.

IndyD :wall:

 

[IndyDurango]

{Echo mode on}

Another P0420 yesterday. Must be the rear one.

Driveability was unaffected. Cleared the codes with my tuner in 60 seconds and now back to driving.

IndyD :wall:

{/Echo mode off}

 

[greendurango]

What's the procedure for cleaning the injectors?

 

[MWeed]

Just run a few tanks of Chevron through the D. You could also take it to your local mechanic and spend about a hundred dollars for him to hook up a device that runs the engine on a high detergent compound while he makes money working on other cars.

 

[jimbo]

Or add a bottle of Techron to your gas tank. It's the same additive package that's in Chevron gas but at a higher concentration.