My car consumes much fuel

Tiny
CURROBAR
  • MEMBER
  • 1989 DODGE DAYTONA
I have a 1989 dodge daytona 2.5 turbo. Is consuming too much fuel. For a gallon of gasoline I'm only 10 miles. The self-test generates the following code: 51 (Oxigen feedback system lean). I change the oxigen sensor. This have 4 wires ( 2 blacks, 1 white and 1 gray), perhaps, the cables are connected correctly? Perhaps, can tell me where each wire is connected? Or what is the reason for the excessive fuel consumption?. In advance, thanks for your response
Saturday, November 12th, 2011 AT 8:47 PM

3 Replies

Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
Probable causes of an engine running rich are as follows:

1. Excessive fuel pressure can be cause by restricted fuel return line

2. Defective Oxygen Sensors.

3. Leaking injectors and fuel pressure regulator.

4. Coolant temperature sensor out of calibration.

5. Restricted air intake system.
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Saturday, November 12th, 2011 AT 11:08 PM
Tiny
CURROBAR
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  • 4 POSTS
I check the pressure of the fuel pump in the rail and this is 55 psi ( this is correct), I revised the fuel return line and this is NOT restricted. The fuel returns normally. I changed the oxygen sensor with a new one, believing that this was the problem, but with the previous one, also consumed fuel. I change the fuel pressure regulator by one new. I have been tested to the injectors and they have the correct injection level. Here, There are two reasons I do not understand. I change the coolant temperature sensor by one new. HOW can be the coolant temperature sensor out of calibration? I not understand this part. And How can be Restricted air intake system? I have that revised all the vacuum hoses? Please, thank you by you reply.
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Saturday, November 12th, 2011 AT 11:46 PM
Tiny
CURROBAR
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  • 4 POSTS
I check the pressure of the fuel pump in the rail and this is 55 psi ( this is correct), I revised the fuel return line and this is NOT restricted. The fuel returns normally. I changed the oxygen sensor with a new one, believing that this was the problem, but with the previous one, also consumed fuel. I change the fuel pressure regulator by one new. I have been tested to the injectors and they have the correct injection level. Here, There are two reasons I do not understand. I change the coolant temperature sensor by one new. HOW can be the coolant temperature sensor out of calibration? I not understand this part. And How can be Restricted air intake system? I have that revised all the vacuum hoses? Please, thank you by you reply.
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Tuesday, November 15th, 2011 AT 1:24 AM

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