Running rich

[forzainformer2]

Found a new problem on the truck... fixed the upstream O2 and the check engine light turned off for two days, its back on and now the truck is running rich, had a friend hook up their scanner to it and when you start the truck it says the everything is fine till you put the truck under load then the injectors stay pouring fuel like my foot is to the floor.


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[Dirtman]

What are the actual code(s) associated with the check engine light?

 

[RonD]

What year 4cyl, there was a BIG change in 1995 and then again in 1998

So you are getting Black smoke out the tail pipe?
That's Rich running
Rich Code is NOT Rich running it denotes a computer calculation error, same as Lean code does

Gas pedal does not control fuel flow, computer does, gas pedal is an "air pedal" on fuel injected engines.
As you add more air, with the "air pedal" computer will add more fuel

 

[forzainformer2]

What year 4cyl, there was a BIG change in 1995 and then again in 1998

So you are getting Black smoke out the tail pipe?
That's Rich running
Rich Code is NOT Rich running it denotes a computer calculation error, same as Lean code does

Gas pedal does not control fuel flow, computer does, gas pedal is an "air pedal" on fuel injected engines.
As you add more air, with the "air pedal" computer will add more fuel

97 4cyl, the guy had his showing live data and the fuel rate was through the roof from what, he was telling me. Ive been cruising it for three days and been getting 7mpg.


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[RonD]

Thats the STFT(Short Term Fuel Trim) showing HIGH positive numbers, like +25% and above

Which shows up as a LEAN trouble code

If you got a RICH code then it would be STFT -25%

But the 7mpg means engine is actually running RICH not Lean, so really really would like to know the numbers AND the codes?????


But from the 7mpg I would say to check the Fuel Pressure Regulator(FPR) on the engines fuel rail.
Prior to 1998, Rangers used a Return fuel system, running 30psi fuel pressure and an FPR.

The FPR has the fuel Return line and a vacuum line attached, the FPR has a rubber diaphragm inside that can crack and leak, the Vacuum hose will suck that gasoline into the intake causing very low MPG and poor running(Rich code and negative STFT).
Find the FPR, and remove this vacuum hose, check it for fuel, if fuel is in there replace FPR

 

[forzainformer2]

Thats the STFT(Short Term Fuel Trim) showing HIGH positive numbers, like +25% and above

Which shows up as a LEAN trouble code

If you got a RICH code then it would be STFT -25%

But the 7mpg means engine is actually running RICH not Lean, so really really would like to know the numbers AND the codes?????


But from the 7mpg I would say to check the Fuel Pressure Regulator(FPR) on the engines fuel rail.
Prior to 1998, Rangers used a Return fuel system, running 30psi fuel pressure and an FPR.

The FPR has the fuel Return line and a vacuum line attached, the FPR has a rubber diaphragm inside that can crack and leak, the Vacuum hose will suck that gasoline into the intake causing very low MPG and poor running(Rich code and negative STFT).
Find the FPR, and remove this vacuum hose, check it for fuel, if fuel is in there replace FPR

I was never shown codes his scanner just said what was setting off CEL like the o2 sensors. I will check the FPR


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[Dirtman]

In the future always get the codes. Scanning a vehicle without writing down the codes is like wiping before you poop.

There are HUNDREDS of codes, over a dozen just for the 02 sensors. Each one tells a different story. Having a mechanic or buddy say "my scanner said its an 02 sensor issue" is literally useless information.

 

[forzainformer2]

In the future always get the codes. Scanning a vehicle without writing down the codes is like wiping before you poop.



There are HUNDREDS of codes, over a dozen just for the 02 sensors. Each one tells a different story. Having a mechanic or buddy say "my scanner said its an 02 sensor issue" is literally useless information.

Im workin with what im told


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