CEL code 173 O2 sensor rich

[swifteagle1]

Hello,

Here is my first post in this forum.
I have been doing a lot of reading and am exceited about all teh information the community is sharing here, keep up the good work.

I just recently had the CEL com on in my 92 explorer (4.0 - 6 cyl)
When the light comes on my gas mileage plummets, to 15 MPG or less.
I just checked my codes last night and I am getting a 173 O@ sensor reading rich.

I cleaned my IAC, MAF and inspected my air intake tubing for leaks.

Any suggestion on what could be causing this?


Thanks in advance for youe awsome help.

 

[swifteagle1]

My appollogies,

After I posted this topic i did som more research, refining it doen the the code i had recieved.

I found a few topics that seem to have info that will help me.

I will post back if nothing they did works or if I fix the problem.

Thanks

 

[swifteagle1]

Looks like I fixed the problem, let me restate the information for others who come along.

I have a 92 explorer XLT, 6 cyl 4 liter, 4WD, pushrod.

My car began to have trouble starting, it would take two turns of the key before it would crank. i gave it a tuneup with no changes.

Next my check engine light (cel) began to come on while I was driving. it would only come on after i had been driving for several minutes (after the car warmed up). The code was 173 "oxygen sensor reading rich". At the same time my gas mileage dropped from my standard 16 MPG to 12 MPG.
After seeing my MPG drop i believed teh code was correct and the O2 sensor was not the problem.
I checked the vaccume line conected to the fuel pressure regulator for leaking fuel and it was dry. I connected a fuel pressure guage to the fuel rail and the pressure dropped from 40 to 0 pretty quickly after the key was turned on but the engine was not started.

I also listened to the injectors with a piece of garden hose and all seemed to be clicking as they should be.

I decided to go ahead and change the fuel pressure regulator since I had already bought one. I disconnected the battery cable for several minutes to reset the computer and drove it to work the next day. The cel has not come back on since. Also my gas mileage has jumped back up to its normal awful self and now my car starts on the first try.

I hope this info will help someone else in the future.

 

[Brutus93]

Well, It's awesome that you were able to figure that out on your own... quite impressive. I had that happen to my '92 ex about 4 years ago, and I even brought it to my dad (a mechanic at the dealer) and he suggested to change the o2 sensor. After we did that (and I was 4 hours away) it began happening again, and actually I was using about double the fuel, I came on here and read about this dreaded fuel pressure regulator. It cost me about $100, took me 1/2 hour to change, and the problem was solved. Glad you wasted less fuel than I did, LOL!