My 1988 Bronco II intermittantly loses power It starts good the it loses power and then evebtually dies. I had this problem last week I had the same problem I changed the fuel filter and it seemed to fix it until today. It started and ran good then it sputtered and eventually died. I checked the fuel filter again there was gas there so I do not understand the lose of power like a plugged fuel filter
1988 bronco II stalls
- Thread starter raj8567
- Start date
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SunSpot
New member
Hmmm. It would be unusual for this to be an electrical problem, as most often an electrical component either works or doesnt. Unless someone else has ideas in that area, Lets go back to fuel....
The fuel system on that year has a front filter in the frame rail behind the steering box, an electric pump in the frame rail a foot or 2 behind the filter, and farther back another filter/separater thingy with a black bowl. Inside the tank there is a filter screen on the fuel pickup tube. If you think you got some bad gas or have a really dirty/rusty tank I suppose you may need to see if the other filter or pick up screen has crap in them too. Water in system could have similar effect.
Some things to think about or try...
- When you changed the filter, did you notice any water droplets in the fuel?
- Can you blow through the old filter? Was it stopped up or have some dirt in it? (you can check by blowing through the filter from opposite direction of fuel flow on to a white rag)
- Once filter was changed, did you bleed the air out of the injector rail? (thing looks like a tire valve on the injector rail) To do this, with the ignition key ON, stick a small screwdriver or drill bit in the valve (depress the little valve in there like you would let air out of a tire) and see if air or fuel comes out. (put a rag around it so fuel doesnt spray all over the place.) Dont do it when the engine is hot as you dont wanna start a fire!. this is kinda like bleeding brakes, getting the air out until you see fuel. If no fuel comes out, then you have a fuel blocakage / restriction somewhere or the fuel pump is going out. If air comes out for a second then lots of fuel, you may have just solved the problem.
If you continually get air in the injector rail after bleeding it over and over, you might have a fuel line sucking air somewhere behind the fuel pump.
The fuel injection system should always be under pressure when key is on, and with no air in the line. A lack of pressure or air in the lines, will starve the engine.
Dropping the tank and checking the pickup tube is a pain in the a$$ btw... save it for last LOL
The fuel system on that year has a front filter in the frame rail behind the steering box, an electric pump in the frame rail a foot or 2 behind the filter, and farther back another filter/separater thingy with a black bowl. Inside the tank there is a filter screen on the fuel pickup tube. If you think you got some bad gas or have a really dirty/rusty tank I suppose you may need to see if the other filter or pick up screen has crap in them too. Water in system could have similar effect.
Some things to think about or try...
- When you changed the filter, did you notice any water droplets in the fuel?
- Can you blow through the old filter? Was it stopped up or have some dirt in it? (you can check by blowing through the filter from opposite direction of fuel flow on to a white rag)
- Once filter was changed, did you bleed the air out of the injector rail? (thing looks like a tire valve on the injector rail) To do this, with the ignition key ON, stick a small screwdriver or drill bit in the valve (depress the little valve in there like you would let air out of a tire) and see if air or fuel comes out. (put a rag around it so fuel doesnt spray all over the place.) Dont do it when the engine is hot as you dont wanna start a fire!. this is kinda like bleeding brakes, getting the air out until you see fuel. If no fuel comes out, then you have a fuel blocakage / restriction somewhere or the fuel pump is going out. If air comes out for a second then lots of fuel, you may have just solved the problem.
If you continually get air in the injector rail after bleeding it over and over, you might have a fuel line sucking air somewhere behind the fuel pump.
The fuel injection system should always be under pressure when key is on, and with no air in the line. A lack of pressure or air in the lines, will starve the engine.
Dropping the tank and checking the pickup tube is a pain in the a$$ btw... save it for last LOL
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Had similar problems a few years back with my 1989 Bronco II, 2.9, 4WD 5 Spd. Ended up changing the fuel pump and fuel pump filter screen. Not hard to do, just a pain in the but because I had a full tank of gas when I started. Nominal cost, about fifty bucks a few years ago.
The fuel pump on the 1989 Bronco II is in the fuel tank.
The fuel pump on the 1989 Bronco II is in the fuel tank.
Last edited by a moderator:
BroncoJoe19
Active member
Does an '89 B2 have two pumps? or just one?
Could be a bad ground, or weak connector to either pump. IT is possible to have fuel, but not enoguh pressure, an EFI system typically needs a min of 35 psi. A fuel pressure guage is how to test.
IF you have two pumps, the one in the tank is high volume, low pressure. The one on the driver's side frame rail is high pressure. Also there is a fuel pressure regulator. Haynes, and I am sure chilton's manuals give a good discription of trouble shooting the system.
A bad MAP sensor, or vacuum leaks to it may cause intermittent stalling as well as problems in the ignition system. You may be well served by pulling diagnostic codes.
Pull Diagnostic Trouble Codes (DTCs) From your onboard computer.
Your engine and transmission are computer controlled.
The computer uses sensors to tell it a number of different things and it controls actuators that push or pull mechanical levers (kinda). If one or more sensors aren't working properly, the computer goes "blind" and doesn't know what to do. If the computer can "see" but one of the actuators is broken and therefore can't follow the commands of the computer; the engine won't run correctly. The computer is preprogrammed with set values for each of its sensors, and each of its actuators. It will run a self check of all systems, like the space shuttle; it will compare its set value(s) to the value(s) it recieves from its sensors, and actuators. If any sensor or acutator is out of the "normal" range the computer will generate a "code." It will generate some codes on the fly, and others will be stored while you are driving. There is a simple method to "pull codes" out of the computer for one to use for diagnostic purposes.
Earlier versions of On Board Diagnostics OBD 1983-1995 can flash the error code to the dash board and can be pulled in one's driveway without any special tools.
Later versions of On Board Diagnostics OBDII some 1995, and pretty much all 1996 and newer, require one to use a code reader or scanner tool.
Some auto parts stores will scan your engine codes for FREE, you may want to call around. Some will scan OBDII but not the older (prior to 1996) OBD systems.
SO here you go...
How to scan FORD on board Diagnostic Trouble Codes (DTCs) in your driveway
Howto Pull Codes 1983-1995 Broncos, Mustang, F series Trucks, Econolines, 302, 351 and more
Could be a bad ground, or weak connector to either pump. IT is possible to have fuel, but not enoguh pressure, an EFI system typically needs a min of 35 psi. A fuel pressure guage is how to test.
IF you have two pumps, the one in the tank is high volume, low pressure. The one on the driver's side frame rail is high pressure. Also there is a fuel pressure regulator. Haynes, and I am sure chilton's manuals give a good discription of trouble shooting the system.
A bad MAP sensor, or vacuum leaks to it may cause intermittent stalling as well as problems in the ignition system. You may be well served by pulling diagnostic codes.
Pull Diagnostic Trouble Codes (DTCs) From your onboard computer.
Your engine and transmission are computer controlled.
The computer uses sensors to tell it a number of different things and it controls actuators that push or pull mechanical levers (kinda). If one or more sensors aren't working properly, the computer goes "blind" and doesn't know what to do. If the computer can "see" but one of the actuators is broken and therefore can't follow the commands of the computer; the engine won't run correctly. The computer is preprogrammed with set values for each of its sensors, and each of its actuators. It will run a self check of all systems, like the space shuttle; it will compare its set value(s) to the value(s) it recieves from its sensors, and actuators. If any sensor or acutator is out of the "normal" range the computer will generate a "code." It will generate some codes on the fly, and others will be stored while you are driving. There is a simple method to "pull codes" out of the computer for one to use for diagnostic purposes.
Earlier versions of On Board Diagnostics OBD 1983-1995 can flash the error code to the dash board and can be pulled in one's driveway without any special tools.
Later versions of On Board Diagnostics OBDII some 1995, and pretty much all 1996 and newer, require one to use a code reader or scanner tool.
Some auto parts stores will scan your engine codes for FREE, you may want to call around. Some will scan OBDII but not the older (prior to 1996) OBD systems.
SO here you go...
How to scan FORD on board Diagnostic Trouble Codes (DTCs) in your driveway
Howto Pull Codes 1983-1995 Broncos, Mustang, F series Trucks, Econolines, 302, 351 and more
I don't know if fuel is the problem but, F.Y.I. the 86-88 has 2 fuel pumps. There is a pusher pump in the tank (low pressure) and there is a fuel pump on the frame under the drivers seat (high pressure). I don't know what Ford was thinking when they designed this. I have been working on Bronco II's for a few years, and I have said many times that the engineers must have been "smoking crack" when they designed some of the things on these vehicles. Don't get me started !!!! Also, Fords in general are notorious for having ignition switch problems. The switch sometimes starts seperating and can cause a number of problems. The next time you have this problem ,if it's still running, try turning the
switch back a little (you can turn it forward, but make sure it's in drive if it's an automatic so the starter doesn't engage). Hope this helps.
switch back a little (you can turn it forward, but make sure it's in drive if it's an automatic so the starter doesn't engage). Hope this helps.
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