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Ford Bronco Repair Questions and Answers

Question: 1988 Ford Bronco mileage: 96,000. My car passes all the emissions test except for NOX. I have taken it twice now to get my smog test and the first time the NOX was 721 at 15 mph 1457 at 25 mph and the max is 986 at 15 mph and 846 at 25 mph. The second time I took it, it was at 15 mph 773 and at 25 mph 1283. So it passes at 15 mph every time but won't at 25. I just got a new EGR valve. So somehow I need the NOX to go down 400 ppm. If you guys could help that would be great.

Answer: You may have a partially plugged exhaust passage that feeds the EGR valve.

Question: 1987 Ford Full Sized Bronco mileage: 150,000. Hello! Bob and Ken My Bronco runs well when cold, but hesitates when warm. I have changed the usual tune-up items: plugs, wires, dist cap, cleaned fuel injectors. I have also changed the coil, and driveline control computer. The Ford dealer has changed the Hall-effect pick-up (breaker less points), and ignition module. There are a few other symptoms, which may pinpoint the problem. The momentary hesitation/power loss (fraction of a second, just enough to take out and re-apply the driveline slack), that is most noticeable between 2300 and 2500 RPM (no-load or heavy-load) is accompanied by the Tachometer needle momentarily losing power, and falling towards zero. The needle generally falls only two to three hundred RPM, before it jumps back to a very slightly reduced indication. The ignition fail code appears when I do the diagnostic tests (with an Ohmmeter). I was thinking that the next place that I would look is, for a loose connection at the Tachometer, or the condenser at the coil. This problem has been with me for about 3 years, and before I dive under the hood again I thought that I would ask for your help.

Answer: You have done a pretty good job of troubleshooting here. About the only thing left that we could think of based on the symptoms you described is the ignition switch as Fords had problems with them in the past. Another cause could be a poor electrical connection or a faulty ground.

Question: 1986 Ford Bronco mileage: 140000. Recently, while driving at approximately 50 mph, the engine died. When I tried to start it again, the starter turned the engine over but it wouldn't start. I have recently put in a new electric fuel pump and changed all the filters outside the fuel tank. I had the control module tested and it was fine. I replaced the ignition coil and the starter solenoid. I checked the rotor and distributor cap and they were both fine. When I checked to make sure it was firing, it was. Someone suggested I might have a water vapor lock. Do you think this could be the problem? If so, how do I correct it?

Answer: Quite possibly the timing chain has failed. Do a compression check and also check for fuel pressure and spark to each cylinder at the correct time.

Question: 1996 Ford Bronco mileage: 130,0000. I've had the same intermittent problem for about 3 years, have never totally nailed the fix. Now at least it's getting worse, which as far as I'm concerned is a good thing-- at least it's consistent. Here are the long-term conditions and symptoms: runs great, except under 3 conditions-- 1) start and stop traffic 2) city driving in the heat or 3) driving under a load at the end of a long drive. The symptoms for 1) and 2) are poor idling, loss of power, and stalling and for 3) sudden, severe loss of power and stalling. In either case, it may not start for some time (which under these conditions can be extremely stressful). The problem is usually preceded by a gasoline smell or more often, a distinctive, sweet odor different from either gasoline or exhaust. Now, it stalls after even a short city drive. I had the catalytic converter checked today to see if it was plugged-- it wasn't-- but the mechanic made the note that there was a lot of unburned fuel in the exhaust-- he could smell it. He also mentioned a lot of carbon buildup in the exhaust system. Repairs I've made include fuel pump/filter, plugs/wires, distributor, and electronic ignition, and the best results I've had lasted about a year due to the replacement of EKG, sensors & hoses, which at the time were packed with carbon. The mechanic on this job mentioned at the time that he was unable to adjust the idle properly-- it was set as low as possible yet idled slightly fast. Any suggestions about the root of the problem or how to get at it? Thanks.

Answer: The first think we would check would be an internal engine coolant leak. This would account for the sweet odor that you noticed. Also, check the fuel pressure regulator as the diaphragm may be slightly ruptured causing raw fuel to be drawn into the engine.

Question: 1995 Ford Bronco XLT mileage: 80,000. While traveling 65 mph on the freeway the cruise control began to act up and when I pulled over to diagnose the problem it eventually turned out that the speedometer head and the ABS pump both showed electrical failure. The speedometer now jumps at speeds above 35 (checked the vehicle speed sensor it was fine and no codes showed for anything else) and I had to unplug the ABS because it engaged every time I put my foot on the brake. Any ideas on what caused this? Mechanic wants to replace instrument cluster and recheck ABS but I don't want to unless I am sure it is not going to burn out again.

Answer: Sounds like your mechanic is on the right track by replacing the instrument cluster first before doing anything about the ABS problem. Replacing the instrument cluster will most likely fix the ABS problem.

Question: 1998 Ford Bronco mileage: 117,000. I have a habit of putting on the parking brake each night when I leave my car because my driveway is on a minor slant and I feel this is the safest option. This morning, when I removed the brake...it felt as if the brake was somewhat still on. Not fully, more like 50%. I have a short drive to work, about a mile and a half, so I risked it. When I got to work, the rear tire well smelled like burned rubber. What's wrong?

Answer: Sounds like your parking brake is not fully releasing. Have the rear brake drums removed and have the return springs checked.

Question: 1993 Ford Bronco mileage: 80,000. I have a 1993 Ford Bronco 5.0-liter v8 with approx 80k. The truck is very well maintained, since I use it to pull my boat and race car. Although overall it is a good truck and reliable, I have encountered a problem that I am not sure how to solve. The truck has an exhaust leak, which came from a faulty or cracked exhaust manifold on the right side. I have replaced the manifold and figured that would be the cure. Yes, indeed it was, but I encountered a second leak which appears to come from the front of the exhaust manifold. I replaced the gasket w/ a gasket kit, the leak quieted down but you can still hear a small leak. It appears to be coming from under the intake manifold or near it on the right side. Do you have any ideas what can possibly cause such leaks?

Answer: Check the air injection tube in the back of the engine as they have a tendency to rust out.

Question: 1990 Ford Full Size Bronco mileage: 160,000. I have the factory installed am/fm, cassette radio which works fine except that the frequency/clock display cannot be seen. If you take a flashlight and shine it at an angle at the display screen, the numerals can be seen but there is not back light. The push-button lights, etc. work o.k. With the other panel lights. Is this something, which can be done by a person with reasonable electronic repair skills and if so where can the part be obtained?

Answer: There should be a light bulb in the radio that lights up the display. It is no doubt burned out. You should be able to replace it yourself and you can get the bulb at an auto parts store.

Answer: 1993 Ford Bronco mileage: 92,000. My 1993 Ford Bronco runs great on the street. Two weeks ago, I went 4-wheeling and after 2-3 hours, the Bronco died and wouldn't run. It was a 92-degree day and I was climbing up the side of a small mountain in 4-wheel-low drive. After about a 2-hour wait (to see if cooling down will help) I started the Bronco and went down the mountain and drove 25 miles home. I changed the fuel filter and thinking I had solved the problem, I went 4-wheeling again the next day in a different spot. Again, after about 2-hours+ of 4-wheeling the truck started missing and died. Again, a 2-hour rest for the Bronco eliminated the problem. When I took the Bronco to the dealer, the mechanic told me that he could not reproduce the problem in the shop and he would guess that the in-tank fuel pump should be considered the problem. I have a Jacobs Electronics coil and mileage master module ignition system in the Bronco and the dealer Mechanic could not run diagnostics on the Ignition system and did not want to speculate about a non-Ford part. I always keep my eye on the temperature gauge and on the first Bronco stalling event I did notice that the truck was running hotter than I have ever seen the gauge indicate, but it was still within the normal operation lines. On the second event, the gauge indicated normal engine temperature operation. I would appreciate any ideas you could share with me about the Bronco problem. Thanks, Dave

Answer: When the engine dies during your off-road adventures, check for spark and for fuel to find out what is causing your no start problem. Obviously one or the other is failing.

Question: 1991 Ford Bronco 4WD  mileage: 64000. We have had this Bronco to the dealer time after time, and it seems to work just fine for a few hours, and then acts up again. The problem is it runs rough at slow speeds/RPM, cuts out and seems to want to stall. One thing we noticed is that when first started, it only runs the fast idle for a couple seconds before dropping down to normal idle. You just can't take off from a stop without giving it a lot of gas. At higher speeds, there is some hesitation, but it does run better. We have had a complete tune up, plugs, wires, EGR checked and nothing seems to help. The Ford dealer does not seem to be able to solve the problem. Any assistance would be greatly appreciated. Dick

Answer: Your problem could be an oxygen sensor or possible a faulty fuel pressure regulator or you may have a vacuum leak somewhere.

Question: 1995 Ford Bronco Eddie Bauer mileage: 90,000. I have in the last 7 months blown 2 a.b.s. units causing total brake failure. One of the 4 lungers or pistons in the front of the unit, brakes or shears of at the turned recess. The end falls out and allows brake fluid to escape when pedal is pressed. Has there been a common problem with this or any recalls. Can you advice what the underlying problem could be and how to prevent it happening again. BEST REGARDS FROM AUSTRALIA.

Answer: This is the first time we have heard off a failure of the type you described and we know of no recalls in this area. The only advice we have for you without being able to see your car, is to carefully inspect the ABS unit and see if any other component close by is coming in contact with it as you drive breaking it. Also, if you have modified you car, this could be the cause of your problem.

Question: 1985 Ford Bronco mileage: 130,000.  Has a lot of hesitation, no pick-up, could not get out of the way an of oncoming vehicle if my life depended on it. Have changed wires, plugs, coil, EGR & sensor.  One guy tried adjusting the timing, it only got worse.

Answer: Check to see that the catalytic converter is not plugged.  Also, perform a compression check and a fuel pump pressure test.

Question: 1995 Ford Bronco mileage: 90,000.  I have a continuing problem with the distributor gear pin shearing.  I have replaced the distributor, oil pump, and cleaned out the pan many times.  I have even gone to larger pins and harden pins.  I have tested the oil pressure, thinking it could possibly be the problem.  It was about 70 psi at idle and around 90 psi at 3000 rpm.  The distributor seems to retard a little before it shears the pin, usually within the next ten miles.  It usually shears the pin after long durations while at highway speeds, between 3000-4000 rpm.   I am not sure if my cam is walking or if the distributor is getting hot and cause the inner bearings to seal up.  The engine is not the original, but I lost the original from the same problem when the distributor locked up in the block, do to a poorly installed cam bearing.  Does the 351M have a thrust button for the cam?  I cant seem to get it fixed, permanently.

Answer: Your oil pressure is too high causing an extra strain on the oil pump drive pin.  You need a new oil pump.

Question: 1990 Ford Bronco II  mileage: 125,000 My Bronco II has a stock 75-amp alternator.  I would like to install a battery isolator and a second battery due to a stereo system that draws a lot of amps.  My question is that if I swap my 75-amp alternator for a 100 amps or better, will it have any negative effect on my computer or wires?  Any info would be greatly appreciated.  Thanks much

Answer: Installing a larger amperage alternator may require a larger main power wire from the alternator to the battery.  It should have no effect on the computer or on any other component in your vehicle.

Question: 1992 Ford Bronco mileage: 191,000.  Engine consistently running above normal in heat gauge.  I have changed thermostat, new radiator, new water pump, new sending unit, new temperature gauge and complete replaced top end head gasket, checked head while apart.  One side of radiator very hot, as well as heater hoses and upper radiator hose.  Bottom radiator hose seems thermostat is not opening and cold on that side.  No circulation in radiator.  Any hints?

Answer: From what you describe, it appears your thermostat may be in backwards or defective.

Question: 1993 Ford Bronco mileage: 105,000.  Engine starts fine cold.  When I restart it after warming it up, it just cranks and does not start no matter how long I turn the starter over.  However, if I turn the key off after 1-2 seconds and retry, immediately the vehicle runs fine every time.   Thanks 

Answer: Your no-start problem may be one of two things.   The first may be a faulty ignition switch and the second a bad fuel pump.

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