Bad MPG

[RangerRyan]

Went to fill up the bronco today. I calculated it out and I'm only getting 8MPG. With a 3" BL, 32" tires, stock axles, stock gears and the stock 2.8 does this sound right? I really only drive it to school then to work and back which is only a couple miles of 35mph speed. I am really curious if somethings wrong? I am not heavy on the gas and I don't every really get above 3 grand.

 

[doorgunner]

yep...sounds bad...my 350V8 gets 15mpg in town...you gotta remember though--ecach traffic light take 1mpg from what you'd normally get...(I can average 20mpg on the road...go into town & get stopped at 6 traffic lights--and the mpg-readout willslowly drop to 12mpg within 20 minutes of driving in town.....)...

 

[Brownie Mobile]

http://www.therangerstation.com/forums/showthread.php?t=125968
The solution on this thread is the solution to your problem, the ignition. Long story short Ford put in a shitty ignition that overtime will wear out the electronics causing horrible gas mileage. Solution: new duraspark ignition ( information found here: http://www.therangerstation.com/tech_library/2_8Duraspark.html ) Go to a junkyard get the parts install it and get better gas mileage.

 

[Pbheadshots]

http://www.therangerstation.com/forums/showthread.php?t=125968
The solution on this thread is the solution to your problem, the ignition. Long story short Ford put in a shitty ignition that overtime will wear out the electronics causing horrible gas mileage. Solution: new duraspark ignition ( information found here: http://www.therangerstation.com/tech_library/2_8Duraspark.html ) Go to a junkyard get the parts install it and get better gas mileage.

not wanting to thread jack but are you sure? I get terrible MPG in my 88 B2 w/ 2.9, and cant figure a fix for it.

 

[RangerRyan]

That's what I was thinking. I should do it anyways because I'm going with a duraspark ignition 302 when I get the engine rebuilt.

 

[Brownie Mobile]

Farily certain, i get about 8 mpg after having a mechanic tune my carb and thats what ive heard about 60 times on this forum already

 

[kimcrwbr1]

Did you change your speedometer gear for the larger tires. It is set for I believe 14" wheels stock maybe 15 for the B-II. Anyway you can clock it using mile markers on the freeway just remember with larger tires you are going faster than what your speedo says. Another good way to clock your speedo is follow someone and compare speeds on the cell phone figure it on a percentage and you can estimate actual miles traveled when you calc the mileage. You can get a set of speedo gears and try different colors until you get close.

 

[kimcrwbr1]

For larger tires you want to go less teeth on the speedo gear.

 

[kimcrwbr1]

http://www.therangerstation.com/tech_library/Speedogear.html

 

[kimcrwbr1]

I was looking at the calculator you can estimate your speed in light years just wondering where that is applicable.

 

[Brownie Mobile]

I was looking at the calculator you can estimate your speed in light years just wondering where that is applicable.

Even RBV owners can like star trek.... lol

 

[Brownie Mobile]

Also for the OP i have a question does your truck feel incredibly snappy on the throttle when you first start it up? but gets less and less snappy after a minute or two of driving then kind of sets in to a funk where it sits for the rest of the day until it cools down again? This is what i feel and definitely proves that the ignition is crap. I read somewhere that with these ignitions over a certain mileage they have a 100% failure rate

 

[RangerRyan]

It runs very crappy when I first start it. It almost sounds like its missing but once its warm it runs okay not great though. Also I forgot about the speedo. No I didn't change it. It's about 5 mph off. Would that have a huge affect on the trip meter.

edit: I actually have a gps that i can track the distance with so this week I will do that and see what my real MPG is.

 

[kimcrwbr1]

You can try preventive maint on it first. Plugs, wires, cap, rotor, PCV, breather filter in the air filter housing, clean the IAT sensor in the filter housing with rubbing alcohol, disconnect the battery for at least 1/2 an hour to reset the computer. Make sure all the sensors are plugged in when you start it. Another common problem is the EGR air bleed vacuum line that allows the egr to close it is the closest solenoid to the firewall and goes under the air horn on the carb. If you disconnect the vacuum line to the egr while it is running and it runs better the bleed circuit is plugged or not pluged in correct. What it does is allows filtered air in to egr circuit to allow the egr to close when the computer says to. Just somethings to look at before you pull the codes. To test the egr at an idle connect manifold vacuum up to the egr the engine should stall and whenever you clean or change a sensor the computer needs to be reset even if you just unplug a sensor while the engine is running the computer goes wacko. Make sure everything is plugged in before you start it up.