code 172 and 136 with strong rich smell when starting!

[huntman58]

Okay I have searched and I also have had this as a running problem for a time (over 3 years now and I still can not get it fixed!
Here is a link to my thread back in 2009 about it
http://www.explorerforum.com/forums/showthread.php?t=243082&highlight=bad+O2+sensors+dose

it now is showing codes 136 and 172 meaning both Right and left O@'s are saying lean so the PCM is enriching the motor as much as it can.

Okay after that post I have in the last year changed the lower and upper intake gaskets. Went back to a stock coil. Plugs are now only 1,000 miles old same with the wires. I did change out both O2 sensors again so they have been changed an average of every 40,000 miles but in reality in the last 40,000 they have been changed 3 times once because a shop damaged the wires when they did the tranny rebuild. I have a vac gage also in the truck and it is now reading about 14 inches most of the time but every now and then on a slight up grade such as an over pass it will drop to below 5 or 6 inches and then hang at around 12 for 20 to 30 miles.
Once again I have gone over the vac lines and can not find any leaks this includes the vac tee as I did take it off and clean it and check it out after reading a post on her thank you for that info who ever posted it!

So my questions are

1) can an over rich mixture make a motor run hot like this now and then but not all the time or do I most likely have a stat going out? (It was replaced also about a year ago with the intake gaskets.)

2) What is the likely hood that I may have a bad or going out PCM?
I know if it was only one O2 sensor I could by it went bad but both and left and right its hard to think they went out together but then again maybe they went out close to each other and not at the same time any one here of something like this?

3) At what kind of miles do the rings and or heads (valves) normally wear out on these motors?

4) Last any one know of a good way to hide the bald spot from pulling out your hair trying to fix an Explorer?

I would like to keep this thing as I have owned it from about 1996 and later have plans to do a SAS with a SOA lift and make it a toy from the DD it is now but at this point I have to keep it as a DD but the MPG is killing me not that it would ever get great MPG just that it no longer gets any thing worth talking about as a 1/4 tank gets me only about 50 miles and that is no good by any ones book for a stock motor.

Any and all help is welcomed and thanks for all I have learned from this sight also and as soon as a job is found I plan to become an elite member.

 

[BrooklynBay]

Check the coolant sensor with an Ohmmeter to see if it's out of spec. Check the vacuum line going into the fuel pressure regulator for signs of leaking fuel.

 

[huntman58]

BrooklynBay I did check the FPR vac line and have changed out the FPR and line (Vac) as the one on it was bad. Not leaking but also not working as in stuck in the no vac setting for full pressure.

Now the coolant sensor. Thanks for that reminder as even thou its not that old I know how things can be. So I went and checked it and sadly it’s with in spec darn it as that would be an easy fix and cheap to boot
.
Well it’s cooler today and my body is feeling it (I am disabled so it’s not always easy to work on it when I need to or want to as no car port shade or garage here just a dirt lot. Grrr. so today I am going to go under it and take a look at the O2's just for the heck of it and see how they look. I do know when I smoged it this year again it just passed. every thing was great and low but the low speed idle test in that as always the NOX was almost at the limit but then again its a fed 49 state truck trying to pass Calif smog with no EGR system not always easy here and only the cats take care of the NOX when you do not have a EGR so the motor better run good and clean but I have almost 2 years before I face it again . any way will post what I find if any thing so thanks for now.

 

[BrooklynBay]

Did you check the fuel pressure with a gauge? Does the gauge suddenly drop as soon as you turn off the engine? You might have a bad injector.

 

[huntman58]

BrooklynBay fuel pressure is fine. With vac and with out plus the holding and as you said the drop at start up it was almost no drop at all but for maybe 5 pounds. Right now I have to O2's out of it to run some tested on the wires and them also as in bench testing them. I plan to also rerun the temp sensor also as I discovered my battery in my DVM was weak and started to miss read so I am redoing my test to make sure about them . Will be off line tell 7/ 19 or 20 so I will let ya know what I find then. I will say when I pulled the O2's they were covered in soot near the base but not the tip at the openings there. they also were a rust brown color first time I have seen that color on any from working on this thing and many other autos so that has me wondering a bit if I did not get some really bad gas some wear . As a side not would a to large of a mass air flow housing make a motor run lean? I had a 70 mm on it again and it seemed to be okay but it was very shortly after that that this started up again so it’s really got me wondering about it also. May go back to stock once I know the O2's and ETC are okay just to see. So tell the 19th or 20 thanks for now.
Marty

 

[huntman58]

Okay reran my test on the EYC and IAT
ETC at 86 Degs F. = 24.27 on the charts and at 100 = 16.15 and 212 = 2.07
I got at temp 100 so ECT was before warm up - 16.08 and at normal temp warm motor = 2.9
IAT at 14.5 air temp 100F

So my thinking is ETC is close enough to say Good at operating temp Am I wrong?
IAT same thing

Now the O2's they tested okay (sorry did not wrte the numbers down and forgot them now) as both raised and lowered as I heated them up on the bench.
I did clean a lot of black fluff off at the base of them soaked them in gas , sprayed them with Seafoam and then MAF cleaner and let them dry. retested after this and got the same results but of coarse this dose not let you know if there changing fast enough or if there getting stuck once warmed up after say a few minutes.
this test just shows that they can change voltage but nothing other.

Have checked and also found no vac or air intake leaks at all!

so now what? I am lost, but to say I have lost another set of O2's in less then 20,000 miles and have now gone threw 4 sets in under 40,000 miles!
two set at the start were most likely okay but one changed because of miles on them (over 140,000!) and the next set I had one showing lean all the time and the other some of the time and later found out I had just then started to lose my intake gasket and have now replaced them. as for the over heating found that it is a bad connection on the gage sender again so going to just change that set up period!

Also just in case down the line how would one find a single bad injector if the plugs all look the same as in burning?
( Ps sorry for my bad writing skills more of a wrench then a writer.)

 

[Tbars4]

..When was the last time the MAF was replaced?..That, a fuel pump/pressure problem, and /or an EGR problem would be my guess as they are common issues as well as the vacuum leaks and bad o2 wires/sensors are..

..These are all things that the computer expects to be in good working order..If they are not, a sensor will throw a code..

..This might help with the 172..
http://www.explorerforum.com/forums/showthread.php?t=239481&highlight=172

..But I'm leaning toward this one...Get it?..Leaning...

Seriously though, the MAF has been a real issue on the first Gens since day one..
http://www.explorerforum.com/forums/showthread.php?t=106175&highlight=172

..For the 136 I would look at this..
http://www.explorerforum.com/forums/showthread.php?t=249502&highlight=136


..With both your codes..
http://www.explorerforum.com/forums/showthread.php?t=198338&highlight=136

 

[mehedgec]

Maf

 

[huntman58]

T bars and mehedgec thanks for the input! the MAF has about 3,000 miles on it I stole it from my Nefs truck when he blew it up and it became a parts truck for me tell it was junked LOL I did clean it as one of the first things this go around as I learned that one after not cleaning a K and N filter right and getting some oil on it. Talk about one ruff running thing! Makes one think ya blew it up for a bit LMAO!

The fuel pump and pressures are fine with out any real big drop off as in a leaking injector but they do fall a bit as I have a bad check vale in the pump. Will recheck it again as no harms in doing it and I have the time and some one to help me now. Will report back what I find if any thing. It is the OE pump by the way but I have a habit of never running below 1/4 tank. learned that on the hard way years ago on a bike when I switched it to reserve some how and had a long walk / push never want that again and this thing it a lot heaver!

as for an EGR well being I do not have one I would say its not working at all LOL no I have a 49 state 93 so no EGR one of the reasons I bought it along with the manual transfer case.

As for your links will be going back and reading or rereading them as I have spent a bit of time researching this and as I said am at a loss any more but slowly I will find this gremlin and boot it!
Again thanks as any and all info or help is welcomed and I hope to find this devil at the same time I got some cash to fix it once and for all!
So tell I recheck some things again and reread or read all the links (thanks Tbars) and check back in have a good one guys!

 

[huntman58]

Okay I do after reading have a new Question.

On the link Tbars gave about the code 172 the talk went to a pinched O2 wire between the motor and bell housing that had shorted out the ECM!

Well that got me thinking as some years back and yes about the time I started fighting this O2 problem and before I joined here, a shop had rebuilt
(I say that sarcastically by the way as 4 month later I had to have it done again under warranty and then 5 months later again only that time I had a new shop do the work and now a few years later its still running like new . the tranny that is)
Any way putting it back in the too had pinched my O2 wire to were I had to cut it to replace that O2. Never gave it any thought after that as I was still stuck with knowledge of the old cars and motors not these new fangled smog filled computer run jobs! Any way could be I have a bad computer as that side has as far as I can recall given me this problem from that first tranny rebuild on! Same with just passing smog every two years were before it passed easily.

Both codes are only KOER by the way never KOEO! Also never threw a CEL also but every now and then and only after a long hot stop and go run or down hill off the gas coast.

So any way to test just that part of the ECM that runs the O2S?
Also in the AM I plan to run it with out the MAF hooked up and see what happens besides a CEL!

Wow reading back I have been fighting this from at lest 2009 here but I know I was also before I came here too. I had mentioned about the pinched wire and thanks to MrShorty for some other great info as going back and rereading then thanks to T bars links gives me a bigger picture on this it a major problem for me and its a long running one that needs to be fixed . But its leading me more and more thinking a bad ECM more then any thing other but I still plan to do as much testing as I can with what I have to make sure before I throw any parts at it. May run to the pick and pull to get some O2s just to see if the codes go away r change more as a test then any thing!

 

[huntman58]

Lesson learned!

Okay want to know how to feel Dumb? Do what I did, OUT THINK YOUR SELF and forget about doing the basics!
I thought it was O2 sensors or more but as of today no codes.

what did I do?

Changed the MAF back to a stock one from the 70MM one with stock sensor.
Did the above thanks to Tbars4 suggestion!
I was shocked my K & N flat filter was plugged with dirt! Reason I was shocked I thought I had cleaned it only a month or so ago (less then 400 miles and no dirt only Hwy driving!) = never count on your memory as time gets warped!

So I cleaned the air filter besides changing the MAF then reset ECM by pulling its 30 amp fuse and relays! (Hate resetting my radio! and this works for me. I also turn the motor over a few seconds with the key just to make sure I drain the keep alive and learned parameters also)

Ran truck about 26 miles then pulled codes KOEO = pass code! KOEO = pass code again! Yippy this is a first for me in years!

Okay so now why no O2 codes and for years always seamed to have at lest one? Luck maybe but I did clean the Sensors as had nothing to lose ( cleaning see above post for what I did) A note on cleaning not really recommended but faced with replacing felt nothing to lose . Also when re installing them always make sure you use anti seize as doing so I have yet to fight the removal of one besides its location being a PITA!

So end results.
Even an old wench can over look a simple thing! so double check and when someone ask you something on here do not think there not believing you as they may be reminding you of something you over looked! Tbars4 did this for me with out knowing it as to replace the MAF I had to remove the air filter lid and Wa La dirty filter that I over looked from the get go!

Truck runs smooth and good. Vacuum is back were a 200,000 mile plus motor should be. So now we will see! Reason I feel dumb is one of the first things to check when you lose MPG is your air filter yet I over looked it big time and was thinking the worse. Heck I even cleaned the MAF twice just in case so you would think I would have at lest looked at it but no I did not! Can we say DUU! Cost to fix = $00.00 as had all the parts cleaners and oil already!
Lesson learned!
Tbars4 thank you for the reminder even if you did not say air filter directly.

 

[Tbars4]

..Glad to see it all worked out as we all have been there ourselves..

..I find those threads when I'm fixing my stuff and try to remember them for others who are doing the same thing I do......

 

[huntman58]

Love that last smiley as thats what I was doing hitting the wall big time LOL so simple and so 1st thing and yet so over looked but the hint on that MAF was the trick for me to look at the thing and as I said what a shock could not believe the thing even ran to be honest it was that bad! Bet I never do that one again but bet I find a new one to do later LMAO! Again thanks Sir!