O2 sensors reporting lean codes

[SeiGGy]

Hey guys, long time no post...I know...anyhow, got some spare time today and ran the codes on my 93 MTX...(been suckin up gas like a ****** at Madi' Gras) anyhow...

KOEO - 111 (all good)
KOER - 172 (lean front 02) 136 (lean rear O2)

Cylinder tests were all fine too...
being that those were the ONLY two codes...I searched the forums and everyone else that had bad O2 sensors got other codes beyond just the 2 sensors reporting lean...so I'm led to believe that maybe this could be a diff problem? any recommendations on things to check/clean before I run to Autozone next thursday and slap down $80 on O2 sensors (also gotta grab a new A/C Compressor w/ Clutch, so any money saved would definilty be great) I know that the Cat's are ok, because it just passed state inspection and emmissions inspection last month....so they shouldnt be the problem...any help would be great...thanks...

 

[gospeedgo]

I am a Ford tech for a performance shop, and personally havent had anything but bad luck with aftermarket O2 sensors. We use only Motorcraft, they are a bit more money but are "proper" and accurate. Plan on about $65 per. I just did mine last week. Also, very carefully clean the MAF...especially if you use a K+N style filter. THey are notorious for wetting the MAF and causing them to be innacurate. Since you are setting both banks lean, look for a plugged fuel filter as well. If you do the fuel filter first and clean the maf (we use a VERY soft bristle paintbrush to clean them, brake clean is not reccomended!) you may be fine...it will usually take a day or 2 to reset a lean code. If it comes back, check the o2's, or replace them. When you replace them, make sure the connectors are dry inside, and apply some dielectric grease to keep the oil out. Sho's for some reason have a oil contamination problem in some connectors, like the o2's.

 

[wood_e]

Go with Bosch O2 sensors. Search for my user name and lean, you'll find a LONG thread on me tracking down what I thought to be a lean condition only to have it be crappy Borg Warner O2 sensors.

 

[Ishodu]

Maybe it would be a good idea to clear them codes and try to see if you get any more after a bit of driving, that is if you have no idea how long its been since there were last cleared.

 

[Bob Gervais]

Most times lean codes on both banks will point to a vacuum leak somewhere. You may want to start there, before plunking down money for sensors you don't need.

 

[jaded93atx]

Like wood_e I followed every bit of advice offered and cleened the MAF (a dozen times) and checked for vaccuum leaks more times than that, not that all that is bad advice. I diidnt think it could be the O2s because they started spitting out the codes after only 10,000 miles of driving, and they were Ford oem. I nor anybody else could figure it out and I didnt want to throw away money on new O2s when mine were still "new". I was getting horrible gas mileage, my idle was erratic, and the car would stumble and stall while deccelerating. I finally got a hold of a MAC diagnostics tool and watched what all my sensors were outputing on the datastream and could see that everything was checking ok except my O2s which were not switching from rich and the voltages were too low. After a year of screwing around I switched them with Bosch and have been trouble free since and passed Illinois emmissions with super low readings.
Hope this helps

 

[I'll sho u]

Just who actually manufactures the oem o2 sensors for ford? I would bet it is somone like ngk or some outside maker. If we could find out who it was maby we could get oem quality at a lower price.

 

[Ishodu]

IIRC the OEM ones are NGK.

 

[jaded93atx]

I actually feel that Bosch are BETTER than whatever Ford sells as OEM O2s, after all as I understand Bosch literally invented 02s and they do seem to be a better design. They are also 49.99 instead of the 100.00 a piece plus labor that the Ford dealershiped stole from me when I did'nt know better on sensors that lasted just under 10,000 miles.
Although I am only speaking from my 5 years of experience and research with my own sho, it also still could be a bad MAF or vaccuum leak, before throwing money away on ANY new O2s either bench test yours like mentioned on shotimes.com, or do like I did and find a friend with a diagnostic tool that can read real time, and show datastreams, it literally took 10 minutes of driving to diagnose the bad O2s and overshadow any speculations that I received or thought. It will also show you what all your other sensors output voltage readings are while you drive through different performance ranges and conditions in and out of closed loop.
Its not complicated at all and any contradicting or questionable output voltages can easily be researched on this forum or an open search on the net. Some codes on our shos can easily be identified with just simply pulling them, others can be open to speculation because their are many possible causes, yours is and mine was one of those cases.

 

[gospeedgo]

I must say, all my "in the field" knoledge has been with mustangs...and with them, we swear by OEM. It is not unheard of for a dealer to mark up Motorcraft by 100%...we buy wholesale and resell for $64 a piece, so you know they are scamming you if they ask $100. We have had several cars come in with poor drivability and sometimes a check engine light, sometimes not. Ford has their pcm calibrated for OEM sensors...and thats what we like to replace them with. Not all sensors work the same, and the ones you buy over the counter are generic with a Ford connector. I know I wont use anything else...but again, this is all from Mustang experience. This SHO thing is new to me.

 

[jaded93atx]

Yeh I probably looked like a sucka and they were probably right at the dealer, but the Bosches if for not half, then considerably cheaper passed my sho through Cook Counties tough emmisions and got rid of my driveability problems/ bad mileage and... with my 12 year old ride that is all I can ask. It runs good, no CE light, and my mileage has doubled, but going with OEM is always an option????

 

[SeiGGy]

well here's a few more details for you...the fuel filter is only about 20,000 miles old...the car has 178,000 miles on it...and these are the original O2 sensors...all the vacuum lines are brand new, but I havent cleaned out the air intake or the MAF (I'll try that this weekend)...the Air filter is new...and I do get a tad bit of smoke from the tailpipes under very hard acceleration (5-6500rpms) so I'm thining my rod seals need to be done when I go to do my 60k again soon...I'm gonna try and do pretty much everything that needs to be done to this car within the next 2 months, because in September I start a new job in which I'll be driving 45 miles to work everyday, so it'll be putting a lot more milage on it...so I'm lookin at trying to put about 1300 into the car over the next 2 months to try and get it back to pristine engine conditions (then this fall I'm gonna give her a new coat of paint..) anyhow...engine codes were cleared about 3 weeks ago when I installed my amplifier and subwoofers...so those are the only 2 codes its reported...thanks for all the advice guys...oh and if anyone in the burlington area wants to help me with the 60k...let me know...gonna need a engine lift...so any help would be awesome...

 

[NotSoSlowSHO]

Just who actually manufactures the oem o2 sensors for ford? I would bet it is somone like ngk or some outside maker. If we could find out who it was maby we could get oem quality at a lower price.

The factory Ford stamped O2 Sensors Ive seen also have BOSCH stamped on them.

I use Bosch. Stay away from the Borge-Warner.