p0300 AHHHHHH
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Joined: Jun 2010
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From: South Carolina
I had recently done some work to my wifes car after it threw a code for the EGR valve.Turns out the valve wasn't the problem.It was the return passage under the manifold.It had got jammed full of carbon and was affecting the EGR valve function.The OBD picked it up as a EGR valve problem and gave the code for that but it was fine.I took the manifold apart,cleaned the passage with throttle/choke cleaner,gave the throttle body a good bath in it and put it all back together.Light went away and has not returned.Point is,some cars throw codes for problems as a default.Obviously it can't give me a code for a blocked EGR passage so it reverted to something it could give me a code for related to the problem.Lazy O2 sensors are not always a full failure so they may not throw a code,which is I believe what happened to me.Since they just take their good ol' time about sending out their message,the OBD has no choice but to react,usually in a negative random way.Just my $.02 worth 
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Joined: Jun 2010
Posts: 78
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From: South Carolina
no, disconnecting an o2 Sensor will cause the truck to run on the Open Loop fuel & spark tables, and if it doesn't like the results it gets from other sensors (MAP, IAT, etc.) it may change to Limp mode which causes misfires and bad performance, because it will add fuel.
So lets explain open loop for you. Open loop is a set of tables that are setup to bypass sensors in the event of failures and also to read from under WOT or aggressive acceleration that only allows additives up to a certain level and in set increments, which is why knocking must be tuned out of the Open Loop tables to effectively increase horsepower.
Closed Loop is a set of equations in which determines fuel, ignition timing and other running factors depending on engine & head configurations, which is all based upon MAP, IAT, Oxygen, and other sensor variables in order to determine instantaneous running conditions. If you would really like to get into Dodge Specific running equations, You will have to have an intermediate to advanced understanding of fluid mechanics, thermodynamics, and physics for starters, as well as a good foundation in mathematics so we can run through the derivatives and integration required in some calculations.
Removing one or more of the variables required to run in Closed Loop will cause erroneous values to be calculated and thus the computer will execute Open Loop in order to run somewhat correctly, and it will run checks on the system that is having problems in order to determine if Closed Loop can be used.
Now from what the OP has described we have narrowed things down to Plugs and O2 Sensor. The reason we think O2 sensors may be the issue is even though the computer is not indicating a DTC for the sensor all the time the sensor may still be reporting incorrect A/F readings in which causes the computer to either pull or add fuel incorrectly thus causing a misfire.
We also stated that if the new sensor and plugs do not solve the problem the injectors may be the problem, so we have covered that base as well. The bottom line is there is a problem with misfiring, which is caused by one of the following; Bad Air/Fuel Mixture, bad ignition, bad compression, and/or incorrect fuel octane. (there are more but those are the most common)
So in short yes you can run a truck without an o2 Sensor but it will cause poor performance, including but not limited to misfires.
Also, When did I ask for help? This isn't my thread buddy.
Before you go spouting false information why don't you read through the last 7 pages of troubleshooting we've done with the OP.
Otherwise, go increase your post count somewhere else, I don't have the patience today...
So lets explain open loop for you. Open loop is a set of tables that are setup to bypass sensors in the event of failures and also to read from under WOT or aggressive acceleration that only allows additives up to a certain level and in set increments, which is why knocking must be tuned out of the Open Loop tables to effectively increase horsepower.
Closed Loop is a set of equations in which determines fuel, ignition timing and other running factors depending on engine & head configurations, which is all based upon MAP, IAT, Oxygen, and other sensor variables in order to determine instantaneous running conditions. If you would really like to get into Dodge Specific running equations, You will have to have an intermediate to advanced understanding of fluid mechanics, thermodynamics, and physics for starters, as well as a good foundation in mathematics so we can run through the derivatives and integration required in some calculations.
Removing one or more of the variables required to run in Closed Loop will cause erroneous values to be calculated and thus the computer will execute Open Loop in order to run somewhat correctly, and it will run checks on the system that is having problems in order to determine if Closed Loop can be used.
Now from what the OP has described we have narrowed things down to Plugs and O2 Sensor. The reason we think O2 sensors may be the issue is even though the computer is not indicating a DTC for the sensor all the time the sensor may still be reporting incorrect A/F readings in which causes the computer to either pull or add fuel incorrectly thus causing a misfire.
We also stated that if the new sensor and plugs do not solve the problem the injectors may be the problem, so we have covered that base as well. The bottom line is there is a problem with misfiring, which is caused by one of the following; Bad Air/Fuel Mixture, bad ignition, bad compression, and/or incorrect fuel octane. (there are more but those are the most common)
So in short yes you can run a truck without an o2 Sensor but it will cause poor performance, including but not limited to misfires.
Also, When did I ask for help? This isn't my thread buddy.
Before you go spouting false information why don't you read through the last 7 pages of troubleshooting we've done with the OP.
Otherwise, go increase your post count somewhere else, I don't have the patience today...
Dang Izero.......here I am tryin' to explain to you about the B1S1 thing.....little did I know
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Joined: Jun 2010
Posts: 78
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From: South Carolina
How do I go about doin' it? I usually just unhook the neg. cable whenever I do any kind of work on the truck.I don't if know that does anything to the PCM or not.I know it will delete codes but as far as a reset completely I ain't sure about.
Champion
Joined: Aug 2006
Posts: 4,489
Likes: 4
From: New Jersey
Remove the negative, NEVER remove the positive.
Current flows FROM positive TO Negative, so you don't want to give the electrical system a jolt when you reconnect the positive cable, which is why you remove the negative, which halt's current flow and is MUCH less stressful on the electrical systems when you're hooking it back up. That is why you see the sparks and whatnot when hooking the positive back up but you don't see it when hooking the negative back up after doing work. Only Pre-1995 Cars, I've actually seen airbags deploy upon hooking the positive cable up, as well as computers and aftermarket stereo systems get completely wiped out/fried.
I have seen people fry ECUs by doing this, Granted it was on older vehicles that didn't have diodes and fuses to protect against power surge, but anything is possible.
This info is coming from an MECP certified technician so take it from me, always remove the NEGATIVE, unless you're overseas where there is a Positive Ground (really uncommon in the US)
Anyways... This problem still isn't fixed???
Current flows FROM positive TO Negative, so you don't want to give the electrical system a jolt when you reconnect the positive cable, which is why you remove the negative, which halt's current flow and is MUCH less stressful on the electrical systems when you're hooking it back up. That is why you see the sparks and whatnot when hooking the positive back up but you don't see it when hooking the negative back up after doing work. Only Pre-1995 Cars, I've actually seen airbags deploy upon hooking the positive cable up, as well as computers and aftermarket stereo systems get completely wiped out/fried.
I have seen people fry ECUs by doing this, Granted it was on older vehicles that didn't have diodes and fuses to protect against power surge, but anything is possible.
This info is coming from an MECP certified technician so take it from me, always remove the NEGATIVE, unless you're overseas where there is a Positive Ground (really uncommon in the US)
Anyways... This problem still isn't fixed???
Last edited by Izero; Nov 2, 2012 at 01:48 PM.
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Joined: Jun 2010
Posts: 78
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From: South Carolina
Well the new upstream in B1S1 did help some.I can feel and hear the difference.I'm gonna pull the old plugs and put in the new Champ Coppers this w/end.I got my feeler gauge out when I got the new plugs and it's a good thing I checked the gaps.They were pre gapped at .044 like it said but on one of the plugs,the ground electrode was pretty much mashed down against the other electrode so it obviously had no gap or very little gap.If new plugs don't make much more difference,I may take it to the dealer and let them check my injectors.I can do the small repairs (I'm used to working on older cars that don't have all these new fangled sensors and stuff) but that fuel rail and its components I think I'll leave alone and let someone with the skills and tools tackle it.It kinda scares me too mess with stuff that delicate.The dealer will do a diagnosis on the fuel system for 85 bucks so that isn't too bad.I'll let ya'll kow how it goes.
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Joined: Jun 2010
Posts: 78
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From: South Carolina
OK so job done.........I pulled the old plugs and put the new plugs in.Now I just have to wait and see what happens.My wife reminded me of somethin though.The last plug change that was done was by my mechanic and not me..(I know I know.....I had a brain fart is all) Hes a good guy/mechanic though.He's got 20+ years as a Honda tech and he's very honest.I had done the wires and he did the plugs for me.He did use the Champion Coppers with the right OEM number.What he did different from me though,is he used (what I'm assuming was) dielectric grease on the connection end of the electrodes.I didn't use any.Will this make any difference down the road? The truck seems to run fine right now w/out the grease on the electrodes.All in all though,the old plugs didn't look to be in too bad of shape.None had any signs of fouling,fuel or anti freeze on them,which I was glad to see.They had the basic carbon build up and even that was moderate.I'm gonna check the gaps later tonite after I relax for a few hours.From what I see right now though,I don't expect the gaps to be excessive but you never know.If I ain't said so already,I really do appreciate everybodys help and patience while I try to get this figured out.Ya'll are first class without a doubt Thoughts,opinions?
Hes a good guy/mechanic though.He's got 20+ years as a Honda tech and he's very honest.I had done the wires and he did the plugs for me.He did use the Champion Coppers with the right OEM number.What he did different from me though,is he used (what I'm assuming was) dielectric grease on the connection end of the electrodes.I didn't use any.Will this make any difference down the road? The truck seems to run fine right now w/out the grease on the electrodes.All in all though,the old plugs didn't look to be in too bad of shape.None had any signs of fouling,fuel or anti freeze on them,which I was glad to see.They had the basic carbon build up and even that was moderate.I'm gonna check the gaps later tonite after I relax for a few hours.From what I see right now though,I don't expect the gaps to be excessive but you never know.If I ain't said so already,I really do appreciate everybodys help and patience while I try to get this figured out.Ya'll are first class without a doubt Thoughts,opinions?
Last edited by SC_Ram; Nov 3, 2012 at 05:36 PM.
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Joined: Aug 2006
Posts: 4,489
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From: New Jersey
the dielectric grease shouldn't make too much of a difference, it's designed to help current flow, but in excessive amounts it can hinder it.
If all of that doesn't fix the problem then you have something else going on that you might need an ECU logger to continue troubleshooting.
You will need to log each cylinder's misfire count, as well as calculated Load, MAP, Timing, Feedback Knock Correction, RPM, IAT, Injector Pulse Width, Fuel Pump Load, and all Upstream Oxygen Sensor Reading (Air to Fuel), might as well throw alternator voltage on there too for good measure.
Then we can graph the living hell out of all of those values and find exactly what is going on.
by the way... How old is your battery?
Might as well invest in a superchips tuner as your OEM tune might be causing the issue, because of the much higher flow exhaust system. (needs some timing adjustment)
If all of that doesn't fix the problem then you have something else going on that you might need an ECU logger to continue troubleshooting.
You will need to log each cylinder's misfire count, as well as calculated Load, MAP, Timing, Feedback Knock Correction, RPM, IAT, Injector Pulse Width, Fuel Pump Load, and all Upstream Oxygen Sensor Reading (Air to Fuel), might as well throw alternator voltage on there too for good measure.
Then we can graph the living hell out of all of those values and find exactly what is going on.
by the way... How old is your battery?
Might as well invest in a superchips tuner as your OEM tune might be causing the issue, because of the much higher flow exhaust system. (needs some timing adjustment)
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Joined: Jun 2010
Posts: 78
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From: South Carolina
I just put a new batt in on 8-2-12 so it's brand new.The dielectric that was on some of the plugs I thought was excessive so I agree that may be contributing to my troubles as well.I reset the computer this morning so its basically back to spec as far as thats concerned.I'd have to say though,it's running much better for now.Since this misfire is such an intermitten problem,it may be awhile before I know if all this helped or not.My immediate future plans are to go ahead and put a new B2S1 sensor in.I'm think the ones on the truck are originals.The truck has 70K and some change on it so they need to go any how.I'm also going to check and see if my coil packs are up to snuff.I'll loosen the bolts,fire the engine up and one by one,lift the pack off for a second or 2 and see if my idle drops any.I won't leave it out long since I don't want too much unspent fuel going thru my cat. converter.I could have done that yesterday when I had them out but my hands were so beat up and my ribs are/were gettin' to aching from leaning over the rad and hood.I just didn't have the energy.I just wanted to get the plugs done and chill out for a little.I was out there for 5 hours doin those plugs.I was taking my time with it but still 5 hours under the hood is killer.What I did also is as I took the old plugs out and when I opened a new one,I put the old one in the box and marked the box with a Sharpie so I know what cyl. it came off of and if it was from the coil pack or the wire plug.That way I can check the gaps,get a good look at the plug and if I see anything suspicious,I'll know exactly where it came from on the engine.I did a prelim. check yesterday and nothin' jumped out at me.When the service writer told me 85 for a diagnosis,I forgot to ask if that was an ECU log test or exactly what I would get for my money.I can always call 'em back but I think for right now I'll change out that sensor.Then I'm gonna let it do it's thing and see how it goes before I shell out the cash.Thanks again fellas!!!
Last edited by SC_Ram; Nov 4, 2012 at 04:30 PM.