Top 10 1991 Ford F150 Questions & Answers

here is the wire colors and what they do. it is from the factory electrical guide.

1991 Ford F150 Truck Car Stereo Wiring Schematic
Car Radio Battery Constant 12v+ Wire: Green/Yellow
Car Radio Accessory Switched 12v+ Wire: Yellow/Black
Car Radio Ground Wire: Red or Black
Car Radio Illumination Wire: Blue/Red
Car Stereo Dimmer Wire: N/A
Car Stereo Antenna Trigger: N/A
Car Stereo Amp Trigger Wire: N/A
Car Stereo Amplifier Location: N/A
Car Audio Front Speakers Size: N/A
Car Audio Front Speakers Location: N/A
Left Front Speaker Positive Wire (+): Orange/Green
Left Front Speaker Negative Wire (-): Black/White
Right Front Speaker Positive Wire (+): White/Green
Right Front Speaker Negative Wire (-): Black/White
Car Audio Rear Speakers Size: N/A
Car Audio Rear Speakers Location: N/A
Left Rear Speaker Positive Wire (+): Pink/Green
Left Rear Speaker Negative Wire (-): Pink/Blue
Right Rear Speaker Positive Wire (+): Pink/Blue
Right Rear Speaker Negative Wire (-): Green/Orange

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I have wondered why this happens many times in the past. You would think the marks should line up using #1 cylinder but they don't.
It has been a while but I think if you hook up to #5 ignition wire the marks will come up for you.You will need to undo the "spout" connector before setting it to 10 degrees before top dead center. The spout is a two wire jumper clip that should break out of the harness at the distributor.
Warm the engine up for a while so it doesn't stall as easy while you set the timing.

Curtorsey About.com;

On a 1991 F-150 the Fuel Shut Off Switch is located on the left and above where the steering column passes through the floorboard.

1. Turn the Key in the ignition to OFF.
2. Push the Red Reset Button on the Fuel Pump Shut Off Switch
Down.
3. Turn the ignition Key ON for a few seconds, Then turn it OFF,
Now try to start it.

this should be it.

Ford has substantially altered their 1978-86 electronic ignition test procedure. Due to the sensitive nature of the system and the complexity of the test procedures, it is recommended that you refer to your dealer if you suspect a problem in your 1978-86 electronic ignition system. The system can, of course, be tested by substituting known good components (module, stator, etc.)

This system, which at first appears to be extremely complicated, is actually quite simple to diagnose and repair. Diagnosis does, however, require the use of a voltmeter and an ohmmeter. You will also need several jumper wires with both blade ends and alligator clips.

The symptoms of a defective component within the solid state system are exactly the same as those you would encounter in a conventional system. Some of these symptoms are:
- Hard or no starting - Rough idle - Poor fuel economy - Engine misses while under load or while accelerating
If you suspect a problem in your ignition system, first perform a spark intensity test to pinpoint the problem. Using insulated pliers, hold the end of one of the spark plug leads about 1 / 2 inch; (12.7mm) away from the engine block or other good ground, and crank the engine. If you have a nice, fat spark, then your problem is not in the ignition system. If you have no spark or a very weak spark, then proceed to the following tests.

Tell if you are talking about this ignition system...




Hope this help.

Hi, if you have the solenoid on the fender, connect the big wire from the battery on one side and the big wire to the starter on the other side. It doesn't really matter which side, but if there are additional wires that fit on a big terminal, they go along with the battery wire. The smaller terminal marked "S" gets the wire from the ignition switch (via the safety interlock switch). If there is another small terminal on the solenoid, it either goes to the ignition coil or is not used. Please let me know if you have any questions and thanks for using FixYa.

You sound like a bad typical TPS sensor replace it . by the way look at the postion of where its at did the coolant at the hose leak onto it its prone to happen also make sure the PCV hose is not ruptured when thhe vehicle is running

could be you fitted the thermostat in the wrong way around ,or the plastic impeller on the water pump with a steel drive shaft has failed they end up with the drive shaft spinning but the impeller is not turning ,go for the thermostat first though .