running rich

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Sep 23, 2009 | 08:38 PM

Fitzgerald_welding

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running rich

on my 88 f250 5.8 it seems to be running rich, im only getting about 165 miles to a 15 gal tank. also sitting stil i can smell the fuel in the exhaust. any suggestions?

Sep 23, 2009 | 08:59 PM

Conanski

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From: Ottawa, Ontario

Check fuel pressure and pull the codes.

Does it have dual tanks? If so do they both work?

Sep 23, 2009 | 09:24 PM

Popa Tim

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From: Central NY

check the fuel pressure regulator too, look for gas in the vacuum line to it.

when was the o2 sensor replaced last?

Sep 24, 2009 | 01:17 AM

matpasch

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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

Sep 24, 2009 | 09:27 AM

Conanski

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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.

Sep 24, 2009 | 12:58 PM

jfmaz

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From: mid-nowhere AZ desert

Quote:

Originally Posted by Conanski

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.

How would you go about checking into the fuel transfer problem?

Sep 24, 2009 | 12:58 PM

matpasch

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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