Piss poor fuel mileage.. WTF?!
 

Just did a fill up today, and I got a whopping 13.8 miles to the gallon. Truck is a 96 extended cab, 166k on the clock, and runs good. Tires are a 215/75/15 (which shouldnt make much of a difference). Things I know from PO, head gasket was done as the head was pulled and checked when the T belt snapped. I was told that when the timing was set it did not start and run, but when the PO put the timing to where he thought it should be it started and ran. I dont know if its weird or not, but in sub 35 temps the truck starts at 2k revs to 2200 and idles back down. There is no noises in the bottom end, or any unusual pinging. I have done the plugs and wires. I have a new fuel filter to go in yet. I have done the throttle cable zip tie mod as well (big improvement over driveability). Fresh oil as well (5-20 or 5-30, I cant remember at the moment). The other unusual thing I want to mention is a heavy fuel smell when I shut the truck off. There is no fuel on the ground, so any idea of what that could be? Suggestions on how to bring this truck back to at least 20 where it should be?

90% of the fuel consumption is done in 10% of people driving style.
Try changing your driving method, take off slowly, accelerate slowly, don’t mash the pedal when you come to a hill and pass at an even increase in speed, that’s the 90% that eats up the fuel.

My 03, 3.0L, 5-sp, gets around that milage, but with 4.10 gears and 33” tires the little 3.0 is working its heart out to keep me moving. If I drive at 60 and hold things steady I get better milage than my usual 65+ and pedal to metal on hills.

Did you change anything maybe the tire size, that will do it as with mine ?

start with checking codes. sounds like your PCV valve is clogged right up.

Oh that was what I forgot to mention this morning. The CEL is not on and not burned out. I also forgot to mention that there is 3.73 gears in the rear end. I notice when driving 30 miles per hour that 3rd gear keeps the RPM's at around 2500 and 4th gear 1600. The truck lugs in 4th at that speed. I rarely hit 4k on the tach, maybe 3500 since to me the truck feels like it dogs on take off.

thats why you get the MPG you do. anything about 2500, these trucks chug gas. id look at why you need to rev that high. My truck rarely breaks 2,000rpm unless im on the highway, then its at 2300.

the 2.3 is a dog, haluing the same crap as my 4.0. drive less agressive, save gas.

did you pull a plug and check its condition? might want to do that. fuel smell and bad mileage indicates an engine running rich. maybe there are some stored codes?. check that. maybe an 02 sensor / coolant temp sensor on its way out.
if all checks out ok then you could try re-set the computer and relearn the trim tables.
i consistently get over 20mpg in mine.

Plus n wires are new. I was thinking the smell had something to do with the charcoal canister? Like maybe it was getting flooded with fuel somehow? Would the engine run if the fuel hoses were crossed? Is that even possible? I was debating on eliminating the EGR and catalytic as I dont need em out here. I wonder if that would help any? Oh forgot to ask, how hard are you on your truck driving style wise?

just pull a plug and see if it's fouled .. = running rich.
would not recommend to eliminate the cat/egr for a lot of reasons, even if your state doesn't require emissions testing.

the 02 sensor sends signals to the computer which controls the fuel trim
so if it's lazy/failing that would make ur engine go into limp mode and run rich=bad fuel mileage.
doubt it could run with crossed fuel lines.
likely a strong gas smell is not the charcoal canister unless something is blocked somewhere but then it would throw a code.

check for stored codes!
driving style wise i guess i'm mindful the truck is 15 years old but other than that i beat the living crap out of it:shhh:

lol @ beating the crap out of it. This truck of mine was owned by a teenager prior to me. The history I got was that it was handed down from grandpa to teen, teen drove it through high school, then got a new vehicle. I was told that idiot kid used to take this truck out in the woods (2wd) to go hunting. I also saw a pic of it buried in mud up to the cab at one point. Needless to say, I know the thing has been neglected. I have been slowly replacing parts since I know it needs em. I have had this heavy gas smell when I shut the truck off since I got it. When I pulled the old plugs, they didnt look fouled or anything funky. I have run a can of seafoam through, so unless that stuff is a myth, i would think my injectors would be cleaned out. I have a new thermostat (195) to put in, water pump (leaking), upper and lower rad hoses since the ones I have now are soft, and that is about it. I am thinking that when I tear the water pump out, I am going to tear down the timing covers and check the timing. As I might have mentioned prior, the PO had set the timing, but it did not run. So he set it to where he thought it should be, and it ran. I am about 80% of the way to deciding on a V8 swap, so I don't want to throw too much at her. Enough to keep her reliable!

ah now the history is told!

if it was buried it might have a leaking gas filler hose.. but it still wouldn't explain why you only get the gas smell after you turn the engine off.:confused:
i would try the few checks as above and see where that leads you.
the lima is a very strong engine and tough to kill so might be worth keeping

When I swapped the box the fuel filler looked solid. I'll check again though since I know thats a common issue. I figure this is a tough engine since it survived a teenage driver!!! LOL

Have you checked the fuel pressure regulator by chance?? The vacuum line will have a gas smell if bad. I would also just remove the vacuum line and run for a little time to see if gas comes out of the regulator. Worth a quick look.

excellent idea tempfixit:cool:

Well I tore the front of the engine down today, and I verified the timing was set correctly (which it was). I also got the new WP, Tstat, and rad hoses in. I also reset the computer by unhooking the battery. Tomorrow I am changing the fuel filter out. I am also going to air the tires up to 42 as suggested that I read elsewhere. I inspected the MAF? in the air box, looked clean so I put it back in. I was debating on whether or not to pull the IAC and clean that in addition to the MAF. I also did the plug mod where I put the 2 coils to fire on the intake instead of 1 & 1 (plugs looked good and normal). I did not inspect the PVC, but they are cheap, so I will just toss a new one in.

Today I also pulled the vacuum line off of the fuel regulator. No fuel came out running or not, and no fuel smell. I also pulled the cap off the relief valve and that was clean and not spewing fuel or fumes out. I did notice the rubber lines leading to the canister are either rotted, broken, or cut into by the PS pulley. So this coming week, I am heading to napa to get some new vacuum lines. I noticed fuel smell by the gas cap. So, I am going to replace that as well. PHEw, by the time I am done, this truck will be almost new!! LOL

Sounds like my truck, LOL. I'm getting 12-15mpg and it's running super rich. Keep at it and please update this thread if/when you solve it. I replaced my O2 sensor and then it ran too lean, popping back, surging. Runs better (but sucks gas) with the O2 sensor unplugged. Clean the wires in the MAF, it's in the housing leading out of the air box.

Have you pulled any codes from the computer? My CPU wiring harness was eaten by rats so I need to rewire that before I can pull any codes from mine. Mine doesn't throw a CEL because I think the previous owner disabled the CEL light or it burned out.

since you disconnected the battery any stored codes may be lost, but they will come back if something is out of wack during the re-learn process. the cel might light up if it throws a code. then you could check that out further.
you have done a lot so it should help mpg's. good suggestion to clean the MAF with electronics cleaner.

let us know if your mpg's improve.

you don't have 2k lbs of stuff in the bed do you?:mischievo

CC
 

Bad catalytic converter?:suspect:

Nope, no fat girls, empty box, and no spare to boot! Well, I have a spare, just not hanging under the truck :P

Well, the new fuel filter is in. I aired the rubber up to 40.5 all the way around (sidewall calls for 44, room for expansion if im on the highway). I got me Motorcraft parts coming for the fuel cap, O2 sensor, pcv, and a generic rad cap. You wont believe this guys, but the old WP had a ford part # on it leading me to think its original!! Anyways, more progress as it happens, and I will update with the new fuel mpg when I fill next time!

Catalytic Converter looks original as well. The exhaust system is in mediocre shape from the header back. Depending on if I go V8 or not, I will probably yank that cat off and weld in a straight pipe, jeez I hate emissions garbage!

:P
 

Fatnsassyntwiceasgassy! LOL:afro:

Have you checked for any brake drag. Colasped front rubber brake line. Emergency brake not completely realeasing. Just a thought.

Drums are gone, I have the SN95 Mustang disc swap now. The Ebrake is not fully working yet (works for holding on flat ground, not hills). I have not had the front wheels off yet. I need to get in there at some point and inspect everything. I sometimes have a clunk on the drivers side which I am thinking ball joints. When I clean the frame and undercoat it this summer, that is when I'll probably tackle the suspension in the front. I know I have a broken leaf in the rear, but so far, it is holding up.

I don't think 2500 is realistic for a 2.3 Lima extended cab (manual I'm assuming), at least for the lower gears. I shift mine at about 3k for 1st-3rd gear normally and about 2500 in 4th to 5th. Hell I'm running 2900 rpm constantly on the highway at 65 and get 24-25 mpg. But I definitely wouldn't want the rpms any lower, it's making just enough power at those rpms even. But I agree, anything probably above 3k is probably chugging gas with these motors.

We don't seem to have much of a wide efficient powerband lol.



Keep us posted, especially if you just drop the v8 in.

Will do on the V8! I saw a POS dented to shit exploder today with the V8 badge on the fender. Some young kid got in it, I gave him a look and he looked away, but if he hadnt looked away, I woulda motioned for him to roll down his window and asked if wouldve sold that hunk of metal. Eh, there will be others!

Anyways, results so far before the new parts (O2, gas cap, etc) are promising. I have 20 on the trip, and the fuel tank is still pegged on full. This is only my 3rd tank of fuel in the truck, but so far, I think this is promising. I have to say that the truck feels so much different now with what I have done so far. Before I did this work over the weekend, I could not drive this truck in 4th gear at 30 mph. I now am driving the truck at 30 in 4th gear without lugging!! It is absolutely amazing to say the least! I am glad I put this thread up, I hope I can help anyone else with poor fuel mileage with ideas of what to do!

Good to hear man, representing the Mazda's.