running rich
Senior User
Joined: Aug 2009
Posts: 111
Likes: 0
Im having similar issues, crappy milage with my '93 F250 5.8L 4x4 ext cab 5spd, i get 342 km on 72 Liters. Also my 2 week old exhaust pipe is black inside. I checked the vacumm line on the pressure regulator and it is dry, no sign of gas, so should I assume its functioning fine, or at least not letting in too much gas?
I bought a new O2 sensor tonight and will post reasults once I have installed it. - that is if I can get the old rusty, pretty sure - original one out. Any tricks on getting one of these out.
thanks
mat
I bought a new O2 sensor tonight and will post reasults once I have installed it. - that is if I can get the old rusty, pretty sure - original one out. Any tricks on getting one of these out.
thanks
mat
FTE Legend
Joined: Jun 2006
Posts: 31,930
Likes: 1,499
From: Ottawa, Ontario
Biggest causes of bad fuel milage on these trucks are in order of significance..
1) fuel transfer problem between dual tanks
2) blown EEC
3) Blown FPR
4) bad sensors
The fuel transfer problem is the most significant because it makes it appear that the engine is consuming a lot of fuel when it's really just being dumped into the other tank and either gets sucked into the engine via the vent system or is dumped on the ground when the tank overflows.
1) fuel transfer problem between dual tanks
2) blown EEC
3) Blown FPR
4) bad sensors
The fuel transfer problem is the most significant because it makes it appear that the engine is consuming a lot of fuel when it's really just being dumped into the other tank and either gets sucked into the engine via the vent system or is dumped on the ground when the tank overflows.
Tuned
Joined: Jul 2009
Posts: 258
Likes: 18
From: mid-nowhere AZ desert
Biggest causes of bad fuel milage on these trucks are in order of significance..
The fuel transfer problem is the most significant because it makes it appear that the engine is consuming a lot of fuel when it's really just being dumped into the other tank and either gets sucked into the engine via the vent system or is dumped on the ground when the tank overflows.
The fuel transfer problem is the most significant because it makes it appear that the engine is consuming a lot of fuel when it's really just being dumped into the other tank and either gets sucked into the engine via the vent system or is dumped on the ground when the tank overflows.
Senior User
Joined: Aug 2009
Posts: 111
Likes: 0
My tank select switch seems fine, i've been running front and rear tanks dry, and always get 72L back into front tank from empty. And FPR valve was dry at the vacuum line, so assuming it is still working.
Sorry, what's an EEC???
thought change my O2 sensor anyway since the truck seems to bee running rich.
mat
Sorry, what's an EEC???
thought change my O2 sensor anyway since the truck seems to bee running rich.
mat
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FTE Legend
Joined: Jun 2006
Posts: 31,930
Likes: 1,499
From: Ottawa, Ontario
If you run a tank dry and it magically fills up again when you are using the other tank... then you have the fuel transfer problem. If one of your tanks is not working look for signs gas is running out the fill tube or vent system, the charcoal canister below the battery on the frame should only have fuel vapor in it no raw gas.
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