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  #13  
Old 09-29-2013, 02:21 PM
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Re: O2 sensor: Location and testing

Frango100 is right on, but I'll add a little to his comments. If the engine was stone cold when you started both videos, the 2/1 and 2/2 sensors are behaving properly. The delay in startup is because the sensors haven't heated up yet. Both front and rear sensors should take a little time to begin sampling.....should take less than ~40 seconds. The 2/1 sensor appears to be a little slower on the heat up, but once sampling, it seems to be OK. That would not cause an economy hit though. They (the rears) will go low or to zero sometimes, when the RPM is low (like idle or slightly off idle)......usually below ~800-1000 RPM. This is also normal. The fronts appear to be fairly normal too.

Next question, does your Torque divice allow you to monitor long term fuel trim? I'd like to see how that looks, before passing final judgement on the effectiveness of the fronts.
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Old 09-29-2013, 05:30 PM
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Quote:
Originally Posted by jeepgcoman View Post
Frango100 is right on, but I'll add a little to his comments. If the engine was stone cold when you started both videos, the 2/1 and 2/2 sensors are behaving properly. The delay in startup is because the sensors haven't heated up yet. Both front and rear sensors should take a little time to begin sampling.....should take less than ~40 seconds. The 2/1 sensor appears to be a little slower on the heat up, but once sampling, it seems to be OK. That would not cause an economy hit though. They (the rears) will go low or to zero sometimes, when the RPM is low (like idle or slightly off idle)......usually below ~800-1000 RPM. This is also normal. The fronts appear to be fairly normal too.

Next question, does your Torque divice allow you to monitor long term fuel trim? I'd like to see how that looks, before passing final judgement on the effectiveness of the fronts.
Yes it does have fuel trim, 2 banks 4 sensors each, short term and long term. I'll try to get those readings this week. Hey thanks for the help.

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Old 10-01-2013, 12:56 AM
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Re: O2 sensor: Location and testing

Quote:
Originally Posted by jeepgcoman View Post
Frango100 is right on, but I'll add a little to his comments. If the engine was stone cold when you started both videos, the 2/1 and 2/2 sensors are behaving properly. The delay in startup is because the sensors haven't heated up yet. Both front and rear sensors should take a little time to begin sampling.....should take less than ~40 seconds. The 2/1 sensor appears to be a little slower on the heat up, but once sampling, it seems to be OK. That would not cause an economy hit though. They (the rears) will go low or to zero sometimes, when the RPM is low (like idle or slightly off idle)......usually below ~800-1000 RPM. This is also normal. The fronts appear to be fairly normal too.

Next question, does your Torque divice allow you to monitor long term fuel trim? I'd like to see how that looks, before passing final judgement on the effectiveness of the fronts.
Verry interesting. Thanks to all
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Old 10-03-2013, 02:23 PM
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Re: O2 sensor: Location and testing

Quote:
Originally Posted by jeepgcoman View Post
Frango100 is right on, but I'll add a little to his comments. If the engine was stone cold when you started both videos, the 2/1 and 2/2 sensors are behaving properly.
I can't remember on the first video I think it had been driven maybe half hour prior. The second video was shot after being off about 10 minutes.

Here are the fuel trim videos, the first is while driving the second is while parked a revving engine. Not sure if that makes a difference.

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Old 10-03-2013, 06:21 PM
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Re: O2 sensor: Location and testing

I'd start by changing the front sensors.....and probably the MAP Sensor too. These videos indicate your LT fuel trim is indicating a double digit rich condition much of the time, and probably pretty close to setting a DTC. With good sensors (and no exhaust/vacuum leaks) the LTFT (both banks) should indicate near zero, or almost always on the lean (-) side, when cruising, or at idle. When cold, and not up to complete operating temperature, is about the only time the sensor should signal a little on the rich side. You can see, when you're revving it from idle, it goes quite rich (+21%) as soon as you let off the throttle. There will always be a fair amount of movement in the STFT (rich/lean/rich), but the numbers on either side of zero should be in single digit numbers (the closer to zero the better), as they should also be for the LTFT. If your sensors have become lazy or are failing, they tend to become biased toward the rich side. A MAP Sensor that is sending bogus info. to the PCM, can also influence fuel trim signals and the PCM's ability to set the proper fuel mixture.

Edit: Before you change the sensors, reset the adaptives (disconnect the battery for ~5-10 minutes), and monitor your STFT and LTFT to see if it starts reading correctly. If not, then change the sensors. Also, after sensor replacements, reset the adaptives.
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Old 10-03-2013, 07:17 PM
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Great I'll try that, I'm pretty sure I've already put a new map sensor in but I'll check. Just the front 2 O2 sensors right?

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  #19  
Old 10-03-2013, 09:39 PM
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Re: O2 sensor: Location and testing

If you're absolutely sure you don't have any exhaust or vacuum leaks, at this point you don't really need to replace the rears, as they have no effect on the fuel trim. Your 2/1 and 2/2 O2 Sensors seem to be working mostly as they should, once the sensors and cats. are warmed up. At this point the MAP Sensor is not that critical either, unless you suspect it to be an issue. It is just another part to the puzzle that could cause fuel economy issues. Another thing I didn't mention is the EGR Valve. If there is any unprogrammed leakage past the pintle in the Valve, that could cause similar indications to a vacuum leak. Has that been changed at any time? A couple other things, what year is your Hemi? If it's an 05, spark plug wires may also be an issue (high resistance), and any year, the type/style spark plugs (should be copper core) you use and how many miles on them can cause issues.

Normally, if the LTFT is indicating rich (like yours is most of the time) your STFT would show more (and higher) negative numbers in an effort to bring both closer to zero. This is where yours doesn't seem to be responding in a normal way......both STFT and LTFT are plus numbers much of the time. This is my rationale for changing the fronts first. Then let's see what kind of reading you're getting.....both O2's and STFT and LTFT. I would highly recommend NTK Sensors all the way around too. I had trouble with the Bosch ones, and NTK's are what came on the Hemi's (at least mine) from the factory.

I guess this is why, back in the beginning of the thread, I said if the O2's hadn't been changed in a long time, bite the bullet and change them. This could very possibly eliminate a whole lot of gymnastics in the troubleshooting department. I do commend you though for your persistence and eagerness to figure out, specifically, what is causing the problem(s). It also helps us all learn a little about all the different types of issues that can be caused by various components. I would probably do the same, but it certainly isn't the quickest way to hopefully fix a problem. Keep on tinkering.
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Old 10-04-2013, 06:53 AM
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Re: O2 sensor: Location and testing

LOL, I do LOVE to tinker. I know I did PCV with the catch can install, the EGR looks familiar so pretty sure I did that one, the MAP sensor I'm foggy on. Torque has mass air flow and intake manifold pressure readouts also so I'm gonna take a look at those today. It's an '07 and I doubt they have been changed so I will go ahead and swap out the O2 sensors.

EDIT: found my MAP sensor install, a year ago, one of the first things I did when I bought it.
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Old 10-04-2013, 08:27 AM
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Re: O2 sensor: Location and testing

Good that you've changed some of the more common troublesome components. When's the last time you changed the plugs? What type did you install, if changed?

Chrysler vehicles use the Speed Density type fuel injection systems, so they do not have Mass Airflow Sensors. Our systems rely on RPM, manifold vacuum (MAP) readings and other engine sensor inputs to calculate airflow requirements and then use (along with the O2 inputs) preprogrammed fuel "lookup" tables to arrive at the correct mixtures. The O2's then "fine tune" the settings. Things you'd want to look at are IAT and ambient temp. inputs, TPS and coolant temp. None of these will provide you much info. with regard to fuel consumption but, once you are familiar with some of the "normal" readings, you'll be able to recognize anything that may be "out of order". I have screens set up for most all of the engine sensors.....i.e. oil press. IAT, batt. voltage, ambient temp. TPS, MAP, load, coolant temp., O2 Sensors, Cat. temps., fuel gph, fuel status, RPM, EGR settings/error, etc.
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Old 10-04-2013, 09:42 AM
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I changed plugs when I got it then had stalling issues. After 4 trips to dealer they replaced plugs fcm and coil packs on one side, has not stalled in about 5 months. Yeah the MAP sensor did not register. I'm ordering O2 sensors from summit racing, NTK not NGK, $40 each plus shipping.

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Old 10-15-2013, 11:55 AM
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Re: O2 sensor: Location and testing

Ok so I got the driver side changed, thought I was pretty clever when I discovered it was easier to re-attach the wire through the wheel well. Now I'm on the pax side and really don't see how I can detach the wire let alone re-attach it, is there something I'm missing? My hands are too big to get up between the trans and the frame. If I pulled the trans it would be a snap LOL.
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Old 10-15-2013, 01:55 PM
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Re: O2 sensor: Location and testing

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Originally Posted by phottomatt View Post
Ok so I got the driver side changed, thought I was pretty clever when I discovered it was easier to re-attach the wire through the wheel well. Now I'm on the pax side and really don't see how I can detach the wire let alone re-attach it, is there something I'm missing? My hands are too big to get up between the trans and the frame. If I pulled the trans it would be a snap LOL.
Edit: You can see the clip (circled) behind the trans dipstick tube (arrow) and it seems to be attached to the trans because I can not move it.
IMG_20131015_025134[1].jpg
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