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1985 Carbureted 2.8, poor mileage.
Posted: Thu Apr 22, 2010 5:21 pm
by cajun66
Well. I finished the automatic to 5 speed swap. Runs and drives great (even considering the retread mud tires.). Here's the rub: I'm getting a max of 13 mpg. Smells rich too but the catalyst was removed a long time ago. Was thinking of leaning the carb out until it pings then turning the fuel up some. But is the Motorcraft carb serviceable? I also have a Holley carb I could try.
What say you?
Re: 1985 Carbureted 2.8, poor mileage.
Posted: Fri Apr 23, 2010 1:06 am
by Ranger Dave
the jets and power valve can be changed. if it were mine, ide get rid of the 2150 and install a 2100
Re: 1985 Carbureted 2.8, poor mileage.
Posted: Wed Apr 28, 2010 4:42 pm
by Colin
Hey cajun66, I have an 84 that only does 13mpg as well, and that is after a rebuilt carb, new rotor, distributor cap, plugs and wires and new 02 sensor and auto throttle control sensor, and the egr valve cleaned out. So you are not alone. I have read others here who get over 20mpg from their 2.8L Broncos so there is surely something wrong with our's lol. Dave answered your post I see and he is one of the more knowledgable 'players' here, so whatever he said I would take notice of. I have no clue what he said but if you know then try it and see if it helps. I would love to know if it does and then if somebody could tell me what he was saying it would be great. I am real dumb when it comes to proper names or numbers for certain engine parts.
Colin
Re: 1985 Carbureted 2.8, poor mileage.
Posted: Sat May 08, 2010 6:04 pm
by cajun66
I found 2 screws at the bottom front of the carb. Turned them both out 1/2 turn and instantly got a cleaner idle, exhaust isn't so potent, more bottom end power, and so far it seems like I'm getting more miles to a fillup.
Re: 1985 Carbureted 2.8, poor mileage.
Posted: Sun Jul 25, 2010 10:15 pm
by RakerBill60
Those are your mixture screws. What I have done in the past is after it warms up good, let it idle in park, or neutral if ya have a manual, make sure the parking brake is on for safety!
Start with either side, and turn it in slowly until it starts running rough, then turn it back out until it starts idling smoothly, then turn it 1/8 further.
Do the other side the same way, it will take a couple of times to get them pretty close. Do not go by the number of turns for each screw, as each side can have a different setting.
As you drive it, you can tell if it is running rich or lean, and make the appropriate adjustments.