1994 Dodge Dakota Error Code 51

CURTROD58

MEMBER
1994 DODGE DAKOTA

Engine Performance problem
1994 Dodge Dakota 6 cyl Four Wheel Drive Automatic 175, xx miles

My '94 Dakota has started running very poorly. Lack of power and big drop in gas mileage. I have checked the codes and the only one coming up is 51, which is "a lean air/fuel mixture has been indicated by an abnormally rich correction factor". I have had a couple of people say it was the cat convertor or an O2 sensor. Any ideas? This has been a good truck for me but I can't afford to spend too much money trying to figure out the problem.

Thanks, Curt

3 Replies

RASMATAZ

MECHANIC
75,992 POSTS

51, which is "a lean air/fuel mixture

A lean fuel condition can be caused by:

* Low fuel pressure due to a weak pump or leaky fuel pressure regulator. (Use a fuel pressure gauge to check fuel pressure at idle)

* Dirty fuel injectors. (Try cleaning the injectors)

* Vacuum leaks at the intake manifold, vacuum hose connections or throttle body. (Use a vacuum gauge to check for low intake vacuum)

* Leaky EGR valve. (Check operation of EGR valve)

* Leaky PCV Valve or hose. (Check valve and hose connections)

* Dirty or defective Mass Airflow Sensor (MAF). (Try cleaning the MAF sensor wires or filament with aerosol electronics cleaner. Do NOT use anything else to clean the sensor, and do not touch the sensor wires)

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Tuesday, June 9th, 2009 AT 9:53 AM

CURTROD58

MEMBER
3 POSTS

I haven't had a chance to really dig into this problem as I have been really busy moving. One thing I have noticed is that the bores of my throttle body have a black sooty coating. When I mash down the throttle, I get a thick cloud of black smoke out of the tailpipe and is also very sooty. I replaced a very dirty air filter and found that, after a couple of weeks there is a big black spot on the new one directly across from where the valve cover breather from the drivers side valve cover enters the air cleaner housing. Do these narrow down the possible problem?

Thanks!

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Wednesday, June 24th, 2009 AT 9:34 AM

CURTROD58