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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
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.
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.
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.
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.
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.