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1987 - 1996 F150 & Larger F-Series Trucks 1987 - 1996 Ford F-150, F-250, F-350 and larger pickups - including the 1997 heavy-duty F250/F350+ trucks

check engine light code

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Old Oct 28, 2009 | 07:43 PM
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blueeyedfordguy's Avatar
blueeyedfordguy
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check engine light code

Hey guys, my engine has been running weaker, and weaker. I checked the check engine light, and it had a code 31 31 ... what does this refer to? It runs weak with bad fuel economy... Is this connected to my fuel line off the fuel pump having a leak? (I think..) That would cause my efi not to be getting enough fuel to run correctly right??
1988 302 v8
 
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Old Oct 28, 2009 | 08:42 PM
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Ford Fuel Injection 2 Digit Self-test Codes 11-32

All the codes can be found there.
 
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Old Oct 29, 2009 | 07:05 PM
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huh, mine was 31, 31 though. Not just 31. Thanks for your help. If mine is 31, what does PFE or EVP circuit below minimum voltage of 0.24 volts refer to? I Figured it is an electronic component causing problems for the engine. I want to go back to carburated.
 
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Old Oct 29, 2009 | 07:45 PM
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Code 31 (the codes are repeated during the self-test) means the closed voltage of the EGR position sensor is outside (lower than) the normal range corresponding to a closed valve position. On your 302, the EGR valve is just to the passenger side of the throttle body, mounted to the intake manifold.

You said you thought it had a fuel leak? An external fuel leak would definitely kill the fuel mileage.
 
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Old Nov 1, 2009 | 08:11 PM
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Originally Posted by EPNCSU2006
Code 31 (the codes are repeated during the self-test) means the closed voltage of the EGR position sensor is outside (lower than) the normal range corresponding to a closed valve position. On your 302, the EGR valve is just to the passenger side of the throttle body, mounted to the intake manifold.

You said you thought it had a fuel leak? An external fuel leak would definitely kill the fuel mileage.
Yeah, that makes a lot of sence. I hear an egr valve can cause many problems and all. That would cause my engine to run bad, but what effect would the leak in the fuel line cause? Would this cause my engine to run terrible like in "limp mode" because the engine is tring to compensate for this? I really appreciate the help.
 
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Old Nov 1, 2009 | 08:46 PM
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If the leak is big enough it could cause a lean condition if the pump can't maintain fuel pressure and flow. If the leak is external, then fuel is leaving the tank and skipping the engine altogether, which would give you an inaccurate poor miles per gallon figure.
 
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Old Nov 2, 2009 | 08:19 PM
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ok, thanks. I heard the oppisite, that the efi would over compensate and ask for more gas.
 
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Old Nov 2, 2009 | 08:33 PM
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i have an 88 150 and i cant get my codes either not even with an obd1 scanner if you figure yours out let me know what you did
 
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Old Nov 3, 2009 | 04:02 AM
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lennb01,you got to clean your OBD1 connectors really good. i used an electronic contact cleaner.hope it helps.
 
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Old Nov 3, 2009 | 04:51 AM
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ok, thanks. I heard the oppisite, that the efi would over compensate and ask for more gas.
That would be correct. If the fuel line leaks enough where the pump can't maintain the correct pressure, the computer will open the injectors longer to try to inject the proper amount of fuel. However, even by opening the injectors longer, at a lower fuel pressure, the actual amount of fuel delivered could be less than what is required, which would cause a lean condition. The fuel that is leaking out of the fuel line is what is killing the mileage because it isn't being used by the engine to propel the truck down the highway.
 
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