Bronco Forum - Full Size Ford Bronco Forum banner
1 - 20 of 55 Posts

·
Registered
Joined
·
790 Posts
Discussion Starter · #1 ·
Sooooooo i decided to do some calculations on how much im using, from where i work and back is around 14-15 miles and it has 2 steep hills and a couple of lights

So doing a rought Estimate of one week around 100miles, i put 40$ in so around 14.7 gallons= 6.8 MPG

What!?! what the heck is going on,i know its bad but it can be THAT bad
 

·
Charlie don't surf..
'92 Ford Bronco XLT
Joined
·
16,144 Posts
Don't recall everything you've done to your Bronco..Assuming it's had a basic tune up, plugs, plug wires, cap rotor, timing checked..Aside from that, have you checked for any vacuum leaks? What about your exhaust system, any leaks in that? I get about about 8.5 mpg with a 351 and 37 inch tires, so something is definitely not right..
 
  • Like
Reactions: canuckistan97

·
Registered
Joined
·
790 Posts
Discussion Starter · #3 ·
Don't recall everything you've done to your Bronco..Assuming it's had a basic tune up, plugs, plug wires, cap rotor, timing checked..Aside from that, have you checked for any vacuum leaks? What about your exhaust system, any leaks in that? I get about about 8.5 mpg with a 351 and 37 inch tires, so something is definitely not right..
not at all ,havent done any crazy mods and all i done is preventative maintaince

maybe it needs the timming checked, i havent been able to because i dont have a timing light

from what i see and hear i dont have any leaks, all i can maybe say is the egr? cause i can hear some leaking in there, even thou the truck iddles around 500-600 no problems and i just changed the map and iddles great

rolling resistance maybe?
 

·
Super Moderator
Joined
·
29,132 Posts
Yo Fox,
As, A#1 LTC Bill Kilgore (jermil01) advised.
See my Vacuum leak test in post #11 incl jowens126 's HVAC Control Panel info @ Help with dtc codes and idle
E4OD Transmission Control Indicator Light (TCIL) is a LED with an overdrive on/off switch at end of the Transmission shifter stalk; flashing OD light is an indication of a transmission related trouble code in the Powertrain Control Module (PCM).
The transmission control switch is a momentary contact switch. When the switch is pressed, a signal is sent to the powertrain control module (PCM) (12A650). The powertrain control module then energizes the transmission control indicator lamp and the coast clutch solenoid, applying the coast clutch to provide engine braking and cancels fourth gear operation; does it cause the lamp to glow?
The TCIL indicates overdrive cancel mode activated (lamp on), electronic pressure control circuit shorted or monitored sensor failure (lamp flashing).

Try a Self Test for Diagnostic Trouble Codes (DTC)s by my pal, BroncoJoe19 @ Code Reader

No codes; see Table 14;
178587


Pull vacuum line off of the Fuel Pressure regulator, if any fuel or aroma thereof, replace regulator.
 

·
Registered
Joined
·
790 Posts
Discussion Starter · #5 ·
Yo Fox,
As, A#1 LTC Bill Kilgore (jermil01) advised.
See my Vacuum leak test in post #11 incl jowens126 's HVAC Control Panel info @ Help with dtc codes and idle
E4OD Transmission Control Indicator Light (TCIL) is a LED with an overdrive on/off switch at end of the Transmission shifter stalk; flashing OD light is an indication of a transmission related trouble code in the Powertrain Control Module (PCM).
The transmission control switch is a momentary contact switch. When the switch is pressed, a signal is sent to the powertrain control module (PCM) (12A650). The powertrain control module then energizes the transmission control indicator lamp and the coast clutch solenoid, applying the coast clutch to provide engine braking and cancels fourth gear operation; does it cause the lamp to glow?
The TCIL indicates overdrive cancel mode activated (lamp on), electronic pressure control circuit shorted or monitored sensor failure (lamp flashing).

Try a Self Test for Diagnostic Trouble Codes (DTC)s by my pal, BroncoJoe19 @ Code Reader

No codes; see Table 14;
View attachment 178587

Pull vacuum line off of the Fuel Pressure regulator, if any fuel or aroma thereof, replace regulator.
hey miesk!

ill check the fuel pressure regulator

Also the transmission is working fine, no flashing on the colum shifter at all and it works as intended
 
  • Like
Reactions: miesk5

·
Registered
Joined
·
790 Posts
Discussion Starter · #6 ·
Don't recall everything you've done to your Bronco..Assuming it's had a basic tune up, plugs, plug wires, cap rotor, timing checked..Aside from that, have you checked for any vacuum leaks? What about your exhaust system, any leaks in that? I get about about 8.5 mpg with a 351 and 37 inch tires, so something is definitely not right..
exhaust i cleaned it when i was redoing the transmission,everything is fine maybeabit restrictive because of the 2 Cats, going to have some one weld me a single CAT and maybe get some headers
 
  • Like
Reactions: miesk5

·
~*~*~*~*~*~*~
Joined
·
10,473 Posts
Timing is crucial. Without it being properly timed, you're not going to get good mileage.

Just for the record, I just went up north this weekend. I filled up, drove 204 miles then tapped back off. There was a lot of wind and a heavy foot too. 13.5 gallons to fill back up. This puts me at 15.1 MPG. Not too bad I think.
 

·
Registered
1986 Eddie Bauer 5.0EFI AOD Full length headers Y pipe into single 3" Magnaflow 3" factory exit
Joined
·
986 Posts
You had no codes now, correct? It definitely shouldn't be that bad, 12mpg at worst. Does your oil smell like fuel??

I had that bad air intake temp sensor go bad and it dumped fuel on me, but it ran really bad & I had a code as well. Have you checked your fuel pressure readings? I'm getting15-16mpg just for reference & when my EGR was brought back to working condition, that helped out my mpg. Keep at it, you'll get it! It takes persistence, but you'll become an old Ford efi expert in time.
 

·
Registered
Joined
·
790 Posts
Discussion Starter · #9 ·
You had no codes now, correct? It definitely shouldn't be that bad, 12mpg at worst. Does your oil smell like fuel??

I had that bad air intake temp sensor go bad and it dumped fuel on me, but it ran really bad & I had a code as well. Have you checked your fuel pressure readings? I'm getting15-16mpg just for reference & when my EGR was brought back to working condition, that helped out my mpg. Keep at it, you'll get it! It takes persistence, but you'll become an old Ford efi expert in time.
alright!!!
air intake temp? i dont think mine has that cause its a 92

also it doesnt smell like fuel, its pretty good on the oil
 

·
Registered
Joined
·
790 Posts
Discussion Starter · #10 ·
Timing is crucial. Without it being properly timed, you're not going to get good mileage.

Just for the record, I just went up north this weekend. I filled up, drove 204 miles then tapped back off. There was a lot of wind and a heavy foot too. 13.5 gallons to fill back up. This puts me at 15.1 MPG. Not too bad I think.
ill see if some one can give me a hand on the timming
 

·
Charlie don't surf..
'92 Ford Bronco XLT
Joined
·
16,144 Posts
you definitely need to check the timing try to sort out any leaks, exhaust or otherwise. That can definitely hurt your overall mpg. good luck and let us know what you find.
 

·
Premium Member
If it is not a Bronco, it's just not worth driving.....
Joined
·
1,900 Posts
Just out of curiosity how are you figuring your mileage?
I see in your post you said you put in $40 worth of gas...

Are you filling the tank up the same each time? When I fuel up it is always topped off with as much as I can get in the tank. The auto cut off on the fuel station kicks in and I still fill it up more with extra squeezes on the fuel nozzle. This is to get the cut off point the exact same every time. This way you know your truck used an exact amount of fuel. If you don't have a solid reference to judge the amount of fuel used it is just a guessing game. My mileage is usually about 12-13 mpg but this is mostly city driving.


How heavy your foot is also makes a huge difference in mileage. Hard accelerations and higher highway speeds burn much more fuel. When I went out west for a road trip I saw about a 2 miles per gallon difference in going 60 mph compared to 70 mph.
 

·
Addicted to Junk
85 Bronco, 309ci I6 w/4bbl, np435, 4" lift, 37" Irok NDs, 4.56 w/ Detroit Locker and tru trac
Joined
·
16,367 Posts
Im with Ken... Fill to the top, reset trip meter or make note of odometer reading. Drive it down to 1/4 tank and fill back up. Divide miles by gallons. If you have non-stock sized tires, Youll need to find the percentage difference and use it to find true miles driven.
 

·
Registered
1986 Eddie Bauer 5.0EFI AOD Full length headers Y pipe into single 3" Magnaflow 3" factory exit
Joined
·
986 Posts
alright!!!
air intake temp? i dont think mine has that cause its a 92

also it doesnt smell like fuel, its pretty good on the oil
Not sure of your exact configuration on a 92, i was just going off of what I found on my 86 EFI, but main point being that the codes lead me to all of the repairs I needed & some were wiring related, where connectors were corroded or broken internally, not sending the signal to the computer.

Do you have the correct temp t-stat in there, verified with a infrared? That can throw fuel curves off too, just like an o2 sensor not sending signal to the computer.

Just think of all the things that would affect fuel. O2, temp, tps, then the timing thesenguys are suspecting. I'd like to see you get to the bottom of this, so we can solve this mystery.

My Bronco gave me all kinds of fits for the first few months of ownership too, till I got all the bad sensors & unhooked/missing things & broken/corroded wires figured out... since then its been good.
 

·
Registered
1996 Ford Bronco Sport 302, auto, 2.5” lift, 4.10 gears, 33” BF Goodrich
Joined
·
37 Posts
Mines a 302, but has 4.10 gears, 33' tires, 2.5' lift and the only engine mod is a Gibson cat-back. I average around 15mpg with a combination city/highway driving
 

·
Driving Stuff Henry Built
-90 xlt, 351w, e4od, man 1356, 3.55, sag, warn hubs, 35s. -73, 400, np435, d20j twin, 35s
Joined
·
8,965 Posts
Just out of curiosity how are you figuring your mileage?
I see in your post you said you put in $40 worth of gas...

Are you filling the tank up the same each time? When I fuel up it is always topped off with as much as I can get in the tank. The auto cut off on the fuel station kicks in and I still fill it up more with extra squeezes on the fuel nozzle. This is to get the cut off point the exact same every time. This way you know your truck used an exact amount of fuel. If you don't have a solid reference to judge the amount of fuel used it is just a guessing game. My mileage is usually about 12-13 mpg but this is mostly city driving.


How heavy your foot is also makes a huge difference in mileage. Hard accelerations and higher highway speeds burn much more fuel. When I went out west for a road trip I saw about a 2 miles per gallon difference in going 60 mph compared to 70 mph.
Im with Ken... Fill to the top, reset trip meter or make note of odometer reading. Drive it down to 1/4 tank and fill back up. Divide miles by gallons. If you have non-stock sized tires, Youll need to find the percentage difference and use it to find true miles driven.
x3. Precise calcs are important. Your "rought Estimate" might be close, but could be way off. MPG, calculated by taking exact miles, adjusted for differences between odometer readings & actual measured miles, divided by exact gallons used is what you should go off of. Then as you make improvements you can use that baseline mpg to see what actually helps.
 

·
Super Moderator
Joined
·
29,132 Posts
Yo Fox,
As Rob_64-365 advised;
Intake Air Temp (IAT); is described by Ford as Air Charge Temperature [ACT] prior to 1992.

ACT Info & pic, engine runs too rich and you have blowby, in a 92

178596
by BigRic

178597
 

·
Registered
1987 Ford Bronco, beefed up 351w, JBG HD rear springs, JBG 4” coil, 10.25 rear posi, Dana 44 posi
Joined
·
426 Posts
I’ve got a modified 351w and highest I’ve seen is 11.3 mpg that was pretty much all interstate driving. Combined with interstate driving to work and a backroads to school I get about 9 mpg. But I’ve been driving a lot and have been spending probably close to $100 on gas a week.
 

·
Registered
95 5.8L MAF XLT, Hedman Shorties/MF SS Y & Muff, E4OD, Man hubs, KYB Quads, 31x10.5x15, 304K miles
Joined
·
1,387 Posts
If you live in a State where they have Emission Testing take it in to a Station and ask if they can do a Tail pipe emission test on the Dyno and see what readings you get. Should be $25 or less. As stated above you need a Thermostat that allows the engine to get hot enough to enter Closed Loop in the computer. Do you have leaky Injectors? Are all your Sensors working correctly? Whatabout Vacuum leaks? What is the Idle Vacuum reading? Is your PSOM calibrated for your current Tires? This should get you in the ball park.
 

·
Registered
Joined
·
790 Posts
Discussion Starter · #20 ·
You had no codes now, correct? It definitely shouldn't be that bad, 12mpg at worst. Does your oil smell like fuel??

I had that bad air intake temp sensor go bad and it dumped fuel on me, but it ran really bad & I had a code as well. Have you checked your fuel pressure readings? I'm getting15-16mpg just for reference & when my EGR was brought back to working condition, that helped out my mpg. Keep at it, you'll get it! It takes persistence, but you'll become an old Ford efi expert in time.
did yours give a code for a bad air temp?
 
1 - 20 of 55 Posts
Top