1985 Bronco 2 has no power?

Schliep96 · Jun 9, 2013

I recently got a 85 bronco 2 for my first rig! 2.8L v6 automatic all original. It runs great 4x4 works good in great shape! Only thing is when put into drive it takes a while to get up to speed and when going up a steep hill it does not go at all up it. it just bogs down, the tires don't even spin when trying to go up. Just recently re-built the carb and that helped a little. I don't know much about car as is i am only 16. Please help i am thinking maybe a tune up plugs, wires but don't know what else. If pics needed i can upload some. Thanks!

kimcrwbr1 · Jun 9, 2013

Where to start? Disconnect the battery and go through and clean all the electrical connections under the hood with electrical cleaner use some dielectric grease to put them back together. Make sure everything is connected before you connect the battery. If you start it with a sensor disconnected it will go into limp mode if you start the motor. Did you count the turns on the idle air needles when you rebuilt the carb if not turn them in to lightly seated and then back out three full turns. Then start it and see how it runs. Even the experienced mechanic will have trouble with that setup if your having computer issues and dont need to pass smog then do the duraspark conversion.

wildbill23c · Jun 10, 2013

First of all Welcome to the Ranger Station.

Check for vacuum leaks, double check your carburetor's adjustment screws on the bottom of the front of the carburetor, turn them all the way in, and back out 3 to 3-1/2 turns, then start it up and fine tune it from there. It takes quite a bit of screwing around with these carbs on the 2.8L's to get them dialed in so they're somewhat good. Another thing to check too, is if your choke plate is open fully after the vehicle has warmed up. Take your air filter cover off, and look at the long plate on the top of the carb, if that plate is closed after driving the vehicle for a few minutes, you need to get the choke fixed. I fixed mine by removing the electric choke crap, and manually holding the choke plate open via a heavy gauge wire, it got me through last winter and has been working just fine even currently not having the choke at all.

Make sure all of your sensors are connected if you are still running with the feedback computer. These feedback carbs are a pain sometimes.

Try all of the above checks and fixes, then post back on your results, and we will try and help you out as much as we can. Its hard to diagnose a vehicle sometimes not having it available for testing and physically being able to go out and mess with it.

Hope this helps.

PetesPonies · Jun 10, 2013

The adjustments on the carb needles is for idle and low speed only. They have nothing to do with running above that threshold. So . . is this BII being driven on the road? Or are you just driving it around the field and trails?? I need some more info.

Schliep96 · Jun 10, 2013

It has been driven on the road a couple times and in a field, when in 4x4 low it does great on power only when its not in 4x4 it lacks alot of power.

PetesPonies · Jun 10, 2013

Well lets understand some things. How the transfer case is selected has nothing to do with how well the engine is running; absolutely nothing in common. But in 4wd low the gear ratio is changed such that the truck has quicker take offs. That is what you are experiencing. From what I have read from you, I think the BII might be totally normal . . .but maybe not. The reason I say this is you are very inexperienced. I taught hundreds of auto students your age. I know what they think and say. Compared to new vehicles, this '85 BII is going to be a pig, yep a pig. It is incredibly under powered, right from the showroom floor. The 2.8l is really mismatched in a BII. In a Mustang or a Capri, they were acceptable, that's all, just acceptable. So if you have driven your dads car, or been in your buddy's truck and are expecting the BII to feel like that . . . not going to happen. Oh . and I own an '84. It had the same engine in it, I even had it slightly modified. The important word here is "had". So perhaps you do have a problem which is keeping your truck from even performing as mediocre as it would normally be doing. If so, then I really feel for you, it must feel horrible. But if it runs well in 4WD, then the engine will run well in 2WD . . just very under powered. But maybe it's not running as well in 4WD as it could, so that something could be wrong still. But you are going to have to give us some more information. Do you have an inductive timing light? Do you have a vacuum gauge??

adsm08 · Jun 10, 2013

5.0

Postin' from teh Galaxy

wildbill23c · Jun 10, 2013

Adjust those 2 screws under the front of the carburetor. Those will make a huge difference in the vehicle being sluggish, and having power or not. It takes a lot of patience to get these carburetors to act somewhat normal. Has nothing to do with engine power, contrary to what many people say the 2.8L V6's had plenty of power, no they weren't a racing engine, but they had plenty of power, or at least my Ford Ranger had plenty enough power to tow around a 16' travel trailer all over the country, and tow around a 2 horse trailer occasionally.

Something that will have a huge effect on power loss too, is if the spark plugs and plug wires are bad, if there's a vacuum leak somewhere, air filter clogged, etc.

Start with the basics, do a tune-up, check to see if the choke is operating, if its not that's going to cause huge power issues trying to go up hills if the choke is stuck closed.

Another thing that comes to mind, you catalytic converter may be plugged, if that is the case you'll have severe power loss problems and hills will almost be impossible to climb.

PetesPonies · Jun 11, 2013

Wild Bill, you are absolutely wrong about "those two screws". You need to learn more about them before you make such comments and lead someone to think they will make a difference. They will have NO change in the running of the engine at speed. They are idle mixture screws. They effect the idle circuit and transition circuit only. They have ZERO effect on the main circuit.

kimcrwbr1 · Jun 11, 2013

Thats funny my 2.8 runs like ass at all speeds with the idle air screws too lean. When they were manufactured they adjusted the needles using propane. The problem you run into is the idle speed is controlled by the computer so as you adjust the needles the computer will change the throttle position. Make sure the timing is at 10 degrees with the spout disconnected. Connect the spout wire and turn the idle air needles out 3 1/2 turns and start the motor it should run around 675 rpms. disconnect the idle control motor once the engine is fully warm and adjust the idle air needles for the highest vacuum pressure or engine rpms. First out then back in until the rpm just begins to drop. Do that a couple times on both needles for highes possible lean setting then plug the idle motor back in and the idle should drop back down to 675 rpms. Never run the engine with a sensor disconnected or you will need to reset the computer by disconnecting the battery for 1/2 an hour. Just leave the intake air temp senser on the air filter housing plugged in and set it aside if you need to run it with the air filter off. Also make sure the vacuum line to the air door on the filter is plugged in. I have had the low power pop up a few times and it was because the choke butterfly was not fully open the relay for the choke thermostat is next to the start solenoid check the connection for corrosion?

PetesPonies · Jun 11, 2013

It's not funny, plain and simple you need to learn how a carburetor operates. There are accurate pages on the web, go read and learn. I'm not trying to be a dick, just pointing out the facts and don't want to teach this here, now. Simply put, there are 5-6 circuits in every carburetor. The ones that operate most times, are the idle circuit, the transition circuit and the main circuit. The idle mixture screws are everything in the idle circuit. They have a slight effect in the transition and have zero effect in the main circuit. As more air enters the carburetor the idle and transfer ports/slots are exposed to the incoming rush of air into the venturi and they become useless. This is as much as I'm getting into it. If you want to learn . . look for info and read about these circuits. Good luck.

alwaysFlOoReD · Jun 11, 2013

I know enough about carburetors to get into trouble.... so I don't have any input into the argument.
.....And that's a good thing because what you guys are arguing about is most likely way over the skill level of the OP.
Lets get back to the basics. First buy a manual.
Fuel - For right now just make sure that you have enough fuel, both volume and pressure. If the volume is low, change the filter first, then re-test.
Spark - It won't hurt to do the basic tune-up parts; sparkplugs, wires, cap, rotor, [capacitor?]
Timing - make sure the timing is correct, someone else described the procedure already.
Check all your wiring and make sure all the grounds and connections are clean. Buy a tube of di-electric grease and use it to protect the connections, put it into the connections to keep out water.
Buy a vacuum gauge and google how to use it.
Good luck,

Richard

PetesPonies · Jun 11, 2013

Richard I agree. And that is why I am so adamant in making sure the 16yo doesn't start turning idle mixture screws and expecting it to fix a problem he may or may not even have. I spent many hours helping HS kids try to determine what was wrong with a car of theirs. You first have to really get to the problem, whether it's real or just perceived.

kimcrwbr1 · Jun 11, 2013

There is no arguement he said he rebuilt the carb I am just telling him how he needs to adjust the feedback carb 3 to 3 1/2 turns from lightly seated is the starting point period. Unless he counted the turns before he took it apart then you just return them to the factory setting.

PetesPonies · Jun 11, 2013

His problem was before the carburetor rebuild.

1985 Bronco 2 has no power?

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