Has new plugs, wires, cap, rotor and fuel filter so i dont think it is any of that. Any help on what could be causing this is appreciated. thanks
broncoII problem
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Mountain Made Racing
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- Joined: Tue Jun 12, 2007 5:34 pm
- Location: tennessee
broncoII problem
I have an 87 Ford bronco2 with a 2.9 4x4 and it has started running weak and has a miss and blows a little black smoke when you rev it up.
Has new plugs, wires, cap, rotor and fuel filter so i dont think it is any of that. Any help on what could be causing this is appreciated. thanks
Has new plugs, wires, cap, rotor and fuel filter so i dont think it is any of that. Any help on what could be causing this is appreciated. thanks
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3barSranch
- Posts: 18
- Joined: Wed May 16, 2007 8:43 pm
- Location: i town iowa
- Contact:
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greenmachine89
- Posts: 142
- Joined: Sat Sep 30, 2006 9:44 pm
- Location: Battle Ground, WA
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You could have some valve seals going out or your rings are shot. I would start buy checking all your wires to see if you are getting spark to all cylinders. Then go from there.
1989 Bronco II 8.8 rear Dana 30 Jeep front---RIP
1991 Exploder 6 inch lift 33's---RIP
1989 Bronco II Stock with 32 BFG KM1's
1991 Exploder 6 inch lift 33's---RIP
1989 Bronco II Stock with 32 BFG KM1's
well i believe you said 2.9 ........ on the drivers side of your intake just behind the throttle body there is a motor looking device called the IAC ....
could be it ......
The IAC is usually a cylindrical unit attached to the upper intake manifold. This unit is electrically controlled by the computer, and allows air to flow into the intake at idle, bypassing the throttle plate. The extra air is accompanied by extra fuel to bring the idle up to proper speed, and when cold, allows a high idle condition. These units may become dirty, and need cleaning. Many idle and stalling issues tend to be blamed on these units. Cleaning is achieved by removing the electrical connector, and two screws holding it on. Once off of the vehicle, clean with throttle body cleaner (or a good carburetor cleaner). Continue cleaning until unit is clean, like new; reinstall unit. This is also a good time to clean the intake, and EGR ports (if applicable).
Testing may be achieved by bringing the engine to operating temperature, noting the idle speed (should be within spec). Unplug the unit’s electrical connector, and the idle should drop to about 650 RPM. When the unit is reinstalled, it should return to normal idle speed. If the vehicle does not idle at proper RPM (too low), there are no vacuum leaks, and the TPS calibration is correct, than the unit is most likely faulty.
or it could be your oxygen sensor ......
Oxygen Sensor Testing: (8)
There may be three wires on the O2 sensor; two gray wires and one black. The black should read ground. One gray wire should read 12V with the ignition on, and the other gray wire is the one we are after. Probe this wire with the engine warm, and running with a voltmeter’s (+) probe, and ground the negative probe. While the vehicle is running, the reading should be approximately 0.5V. A reading below this indicates a lean air fuel mixture; a reading above this indicates a rich mixture. If no reading is present, and all connections are good, the sensor is probably in need of replacement.
just a couple of things that i would check
but normally black smoke references a motor running rich ... too much fuel for amount of air .... so the air filter should be checked and if dirty replaced, because if you restrict air flow you enrich the fuel mixture on fuel injected motors.....
hope those thoughts help some
could be it ......
The IAC is usually a cylindrical unit attached to the upper intake manifold. This unit is electrically controlled by the computer, and allows air to flow into the intake at idle, bypassing the throttle plate. The extra air is accompanied by extra fuel to bring the idle up to proper speed, and when cold, allows a high idle condition. These units may become dirty, and need cleaning. Many idle and stalling issues tend to be blamed on these units. Cleaning is achieved by removing the electrical connector, and two screws holding it on. Once off of the vehicle, clean with throttle body cleaner (or a good carburetor cleaner). Continue cleaning until unit is clean, like new; reinstall unit. This is also a good time to clean the intake, and EGR ports (if applicable).
Testing may be achieved by bringing the engine to operating temperature, noting the idle speed (should be within spec). Unplug the unit’s electrical connector, and the idle should drop to about 650 RPM. When the unit is reinstalled, it should return to normal idle speed. If the vehicle does not idle at proper RPM (too low), there are no vacuum leaks, and the TPS calibration is correct, than the unit is most likely faulty.
or it could be your oxygen sensor ......
Oxygen Sensor Testing: (8)
There may be three wires on the O2 sensor; two gray wires and one black. The black should read ground. One gray wire should read 12V with the ignition on, and the other gray wire is the one we are after. Probe this wire with the engine warm, and running with a voltmeter’s (+) probe, and ground the negative probe. While the vehicle is running, the reading should be approximately 0.5V. A reading below this indicates a lean air fuel mixture; a reading above this indicates a rich mixture. If no reading is present, and all connections are good, the sensor is probably in need of replacement.
just a couple of things that i would check but normally black smoke references a motor running rich ... too much fuel for amount of air .... so the air filter should be checked and if dirty replaced, because if you restrict air flow you enrich the fuel mixture on fuel injected motors.....
hope those thoughts help some
Base Idle Adjustment: (7)
This essentially is an alternate test for the TPS Calibration. The base idle is computer controlled via the Idle Air Control (IAC) motor. To do this crude base adjustment, warm the engine up. Unplug the IAC electrical connector. Restart the engine (if it doesn’t start, screw the throttle plate adjustment screw in, until it starts). Once the vehicle is running, adjust the throttle plate adjustment screw until the idle reaches 650RPM. Plug the IAC electrical connector, and restart the engine. The idle should settle to 850-950RPM. Note that it is best to use an accurate tune up tachometer, not the stock gauge.
This essentially is an alternate test for the TPS Calibration. The base idle is computer controlled via the Idle Air Control (IAC) motor. To do this crude base adjustment, warm the engine up. Unplug the IAC electrical connector. Restart the engine (if it doesn’t start, screw the throttle plate adjustment screw in, until it starts). Once the vehicle is running, adjust the throttle plate adjustment screw until the idle reaches 650RPM. Plug the IAC electrical connector, and restart the engine. The idle should settle to 850-950RPM. Note that it is best to use an accurate tune up tachometer, not the stock gauge.