Need help with codes...

[clappedout92]

I apologize up front for the lengthy post, but I could use some help. I have a 120k '92 that's been fairly trouble-free the last 3-4 years (no, seriously!). Until a couple months ago, that is. At first I noticed the fuel mileage dropping pretty seriously, going from about 350 miles per tankful since new to around 240 or so now. Then the CE light starting coming on every day, on the way to and from work. The local Ford service dept. pulled the following codes:

KOEO: 111.10.173.176.177
KOER: 116.136

The 116 is dubious to me, as this car has been extremely cold-blooded all its life. I dropped the car off the evening before and I'm guessing the coolant temp wasn't high enough before running the EEC test.

They told me the MAF sensor was bad and offered a new one for $360 (which included $80 for the EEC test). By the way, the MAF sensor is a C&L 73mm unit installed by Doug Mellum at Performance Plus back in 1994. I declined and instead went home and cleaned the sensor with a Q-Tip doused in brake cleaner, per Doug's advice. The next day, no CE light. Terrific! But, and there's always a "but" with these cars it seems, the next day, at the exact same spot, the CE light came on as I was heading to work. Not wanting another $80 diagnostic charge, I bought my own code reader. Here is what I pulled myself:

KOEO: 111.10.176.528.542
KOER: 136.538

Based on what I've come across from searching the forum for specific codes, I'm inclined to ignore the 528, 542, and 538 for now, leaving the 176 and
136. These indicate to me that the O2 sensors are detecting lean conditions.

My questions are these:

1. Do I have bad O2 sensors?
2. Do I have a bad MAF sensor?
3. Do I have unmetered air in the system from a vacuum leak somewhere?
4. Do I have all three, and, God forbid, possibly more?
5. Or is it just not that simple?

The car starts and runs fine, has good pick-up, no stalling, no stumbling, no real driveability issues. Just the atrocious gas mileage and the CE light.

Thanks in advance for any thoughts anyone may have!

 

[jedhead]

10 is not a valid code. All GEN2 SHO's have 3 digit codes. Are all the numbers you are reading correct?

Bob

 

[tgsho]

jed, do you know lots about codes? if so please read my thread about the new SHO and troubles.... thanks in advance

 

[clappedout92]

Thanks for the quick response Bob. Yes, I realize 10 is not a valid fault code. It's just a separator code. I reported what was on the dealer's repair order and what I read directly out of my own code reader. You'll notice that the remaining codes mentioned in my post are all three digits...

 

[armerdan]

If it were me I would first check for vacuum leaks, at least visually, there really aren't that many to check, however, if it were a large enough vacuum leak to lean out your mix I would think you would have either a rough/stumbling or high idle (sometimes if you have a big enough vacuum leak your PCM sends more fuel to the engine to make up for the extra air so you get a high idle).
Also if it were a vacuum leak, it would lean out BOTH sides equally, so you would get a lean code from BOTH o2 sensors:type:
So all that said a pair of Bosch o2 sensors (GASP run away, No not BOSCH!!!) from auto zone only runs you about $100.00 and they have a 1 year warranty. Hey I've been running a pair of Bosch o2's on mine for a couple thousand miles with no problem. Also they are not very hard to change, just wait till the car is not too hot, spray some PB blaster (really great stuff) on em, and when you put the new ones in put some of that thread compound stuff on them.

 

[SASHO91]

Give the MAF a good cleaning for starters.
Also, I would switch back over to a stock MAF housing.

After that, some new plugs couldnt hurt(throw in some cheap coppers for the time being)

As far as O2's and thier codes.. i would first start checking for Vacuum leaks. There are a few ways to do this.. the simpliest way is to spray the intake manifold with carb cleaner, or the like, and listen for an idle increase. The stock rubber runner connectors are know to split, and cause vacuum leaks. (i just went to AutoZone and took a connector with me and matched it to a radiator hose that i could get 6 connectors out of, cant recall the PN)
After that, if the problem still exsists, you may want to change out the ECT (the one for the EEC NOT the one for the dash gauge), and check Fuel Pressure.

 

[clappedout92]

Thanks SASHO91 and armerdan. I think I'll do the vacuum leak check first. As I mentioned in my original post, the MAF sensor has already been cleaned. I was hoping that would do the trick, but no dice. A couple of O2 sensors wouldn't hurt, I suppose. I was so hoping I wouldn't have to crawl under this thing again.

That's what I get for hanging on to it. But geting rid of her would be like kicking out one of my own kids...

 

[doclees]

Trust me, kicking the kids out is much more pleasurable.