Questions and Answers
Dodge Spirit Code 51
Q. Hi Vince, I have a 1991 Dodge Spirit, 2.5 liter TBI, 112,000 miles, P/S, A/C and cruise control. About a year ago, I was blowing black smoke while accelerating, until the car came up to full operating temperature. I was also getting a code 51 (Lean mixture).
I replaced the O2 sensor and things seemed okay. MPG seemed reasonable to me at about 23 city/country. It has started to do it again. Starts fine, idles okay, then when I start out of the drive, It misses, has lose of power, and blows black smoke. Also giving code 51 again.
Am I fixing the right thing, by replacing the O2 sensor, or is it something else. I don't mined buying and installing an O2 sensor a year, but if I'm fixing a result rather than the problem I'd sure appreciate knowing it. Could it be the brand of O2 sensor I used? Bosch instead of Mopar.
Thanks in advance for any help.
VinceA. Code 51: Lean air/fuel condition. Oxygen sensor signal input indicates lean fuel/air ratio condition during engine operation. What this code is saying is that the O2 sensor detected a lean air/fuel mixture. This doesn't mean the O2 sensor is bad. In essence what you did was kill the messenger.
What you have to do is locate the cause of the lean mixture. It could be low fuel pressure, dirty injectors or a vacuum leak.
Additional Information provided courtesy of ALLDATA
