Contact Me @ FSB or Bronco Zone Forums Home Bronco TSB Summaries Recent Updates Unique Visitors: 68841	FORD BRONCO -> IGNITION; plugs/wires, distributors, MSD, firing orders; switch & ignition actuator rod, TSBs... WELCOME to MIESK5's BIG BRONCO LINKS - We now have over 30,000 LINKs! This is a 4x4 Big Bronco, Truck & Van Technical & Parts LINKS site developed by the MIESK5 Family & is not affiliated with the Ford Motor Co. in any manner. Although we initially developed this site for 78-96 Big Broncos, information in many Links also applies to F, E Series & Cars Select A Category: System; Davis Unified Ignition (DUI), Duraspark, Thick Film Ignition (TFI), MSD, Jacobs, Crane, PerTronix 351/400M Ignition Parts Reference w/Ford part numbers Ballast Resistor Coil Distributor - Gear, Spark Output (SPOUT) - See Ignition System; Thick Film Ignition (TFI) Section for Ignition Module, PIP, Stator, etc. Firing Order General Information Ignition Components, Wire & Cable , etc. Parts Catalog, Ford Spark Plug Spark Plug Wire; Routing TSBs Switch & Ignition Actuator Rod & TSBs Timing Troubleshooting Select A Link: "...SLOW cranking is battery, terminals, cables, relay, or starter. LONG cranking is compression, vacuum, fuel, oil pressure, or ignition..." Source: by Steve83 (Steve, That dirty old truck) at FSB ACCEL Ignition Instruction Sheets Source: by ACCEL at prestoliteweb.com Auto Repair Reference Center Repair Manual, Mostly Chilton; many local library's offer free online access for their members; just log-in w/your library Card # and password; incl. all Broncos, & many MAKES! 1951 to 2009; some years (85-96, I believe) include: FULL Technical Service Bulletins and Recalls, Labor Hours per repair (plug in appl info); Wiring Diagrams, Vacuum Diagrams (in DRIVEABILITY AND EMISSIONS CONTROLS Section), Specifications (torques, etc.) & Maintenance Intervals Source: by arrc.epnet.com Break-Out Box Overview; "...The breakout box put itself between the engine and the computer, and allowed the user to rapciously access the information being exchanged. They are simply a pinout board, mounted in a box, with associated cabling, like this... You can see the way the cabling hooks into the computer and then bridges into the automobile system. A closer look at the pinout board, little holes numbered to correspond to the numbered wires in the connector:The output is readable with a high impedance (this is IMPORTANT- Digital Volts Ohmeter (DVOM) No cheap knockoffs here, they may fry the computer by introducing their own voltage.) Not as fancy as a scanner which decodes the meaning for you, but valuable nonetheless because you can always look up every meaning of the output signal somewhere. Like on the factory manual CD or in the manual itself! FORD decided to make maximum use of the breakout box, and designed add ons to allow you to look at other systems. Here for example, is a harness (still looking new in the wrapper) that hooks into all the Distributorless Ignition System (DIS). It connects to the sensor connectors... allowing you full access to the signals, even while the engine is running: TFI (thick film Ignition) Yes there is a cable for this. Mine cost me $15. Here is the diagram ...There was an adapter for the breakout box that read the brake codes, AND... AND... did the procedure for properly bleeding them. It was called the anitlock Brake Adapter (ALA) and looks like this when installed in the unbilical for the breakout box: Betwen $125 and $200 on E-bay. Worth every penny if you want to look inside that engine..." Source: by Glacier991 (Chris) at explorerforum.com Build Date Stamp Location in a 96; "...The vehicle build date stamp is a four-digit number representing month and day of manufacture. On Bronco and F-150, F-250, F-350, the vehicle build date is stamped on the front surface of the radiator support on the passenger's side of the vehicle. For example, for a build date of January 24, the vehicle build date stamp reads 0124; for a build date of October 21, the vehicle date stamp reads 1021. Yellow ink is normally used for the date stamp. When the marking surface is painted the body color, the date stamp will be marked in red ink. Units from the Ontario Truck Plant (Code C) will be marked with silver ink..." in 1996 F-150, F-250, F-350, F-Super Duty and Bronco Workshop Manual Source: by Ford via thedieselstop.com Chilton Manual for 66 - 81 Bronco, Scanned Copy Source: by Chilton via broncocity.com Detonation & Pre-Ignition (or Pinging); "...Check for over-advanced ignition timing. Too much spark advance can cause cylinder pressures to rise too rapidly. If resetting the timing to stock specifications doesn't help, retarding the timing a couple of degrees and/or recalibrating the distributor advance curve may be necessary to keep detonation under control. A knock sensor can usually be tested by rapping a wrench on the manifold near the sensor (never hit the sensor itself!) and watching for the timing change while the engine is idling. If the timing fails to retard, the sensor may be defective -- or the problem may be within the electronic spark timing control circuitry of the computer itself. To determine the cause, you'll have to refer to the appropriate diagnostic chart in a service manual and follow the step-by-step test procedures to isolate the cause. Sometimes a knock sensor will react to sounds other than those produced by detonation. A noisy mechanical fuel pump, a bad water pump or alternator bearing, or a loose rod bearing can all produce vibrations that can trick a knock sensor into retarding timing. The Exhaust Gas Recirculation (EGR) system is one of the engine's primary emission controls. Its purpose is to reduce oxides of nitrogen (NOX) pollution in the exhaust. It does this by "leaking" (recirculating) small amounts of exhaust into the intake manifold through the EGR valve. Though the gases are hot, they actually have a cooling effect on combustion temperatures by diluting the air/fuel mixture slightly. Lowering the combustion temperature reduces the formation of NOX as well as the octane requirements of the engine. If the EGR valve is not opening, either because the valve itself is defective or because its vacuum supply is blocked (loose, plugged or misrouted vacuum hose connections, or a defective vacuum control valve or solenoid), the cooling effect is lost. The result will be higher combustion temperatures under load and an increased chance of detonation. Try a higher octane fuel. Check for over-advanced ignition timing. Read" your spark plugs. The wrong heat range plug can cause detonation as well as preignition. If the insulators around the electrodes on your plugs appear yellowish or blistered, they may be too hot for the application. Try the next heat range colder spark plug. Copper core spark plugs generally have a broader heat range than ordinary plugs, which lessens the danger of detonation. Check for engine overheating. A hot engine is more likely to suffer spark knock than one which runs at normal temperature. Overheating can be caused by a low coolant level, a slipping fan clutch, too small a fan, too hot a thermostat, a bad water pump, or even a missing fan shroud. Poor heat conduction in the head and water jackets can be caused by a buildup of lime deposits or steam pockets (which can result from trapped air pockets). Check for a lean fuel mixture. Remove carbon deposits. Low coolant level, slipping fan clutch, inoperative electric cooling fan or other cooling system problem that causes the engine to run hotter than normal. READ MORE..." Source: by Bob at misterfixit.com EEC IV Strategies Source: by unknown at broncolinks.com/gallery EEC-IV System Has NO Control Over the Following Items; "...Fuel quantity and quality; Damaged or faulty ignition components; Internal Engine Condition - rings, valves, Timing belt, etc.; Starter & Battery circuit; Dual Hall sensor; TFI or DIS module; Distributor condition or function; Camshaft sensor; Crankshaft sensor; Ignition or DIS coil; Engine governor module..." Source: by Ford via arrc.epnet.com Electrical and Vacuum Troubleshooting Manual (EVTM) for an 86 (Partial); Speed Control on pages 135-139, A/C & Heater on pages 140-145, Radio on pages 127-129 Source: by Chris B (Blue, bronco boy) at telus.net Electrical Symbols in an 86 from Electrical and Vacuum Troubleshooting Manual (EVTM) Partial Source: by Ford via Chris B (Blue, bronco boy) at telus.net Ignition Switch Pin-Out Diagram & Continuity Testing (Logic Tables) in 80-91 & 92-96 Source: by Steve83 (Steve, That dirty old truck) at SuperMotors.net Ignition System Wiring Diagram in a 94 from EVTM Source: by Mikey350 at SuperMotors.net Ignition Timing Vacuum Switch Depiction; The ignition timing vacuum switch is used on certain earlier models and through vacuum, signals the ignition module to retard spark timing. The amount of retard is controlled by two calibration resistors inside the switch assembly. - 80.6 MB pdf Source: by Ford fordinstallersupport.com Key On Engine Running (KOER) Self-Test Does not Run; On most 1988 and all 1989 and later models, the EEC does not enter the KOER self-test if any of the on-demand codes found during the KOEO self-test are not corrected. If KOEO on-demand codes are present, the EEC will not allow the KOER test to run. In a scan gauge, a “fix all hard codes” message displays when the KOER self-test is selected. Memory codes are problems that the computer has noticed in the past. If for example there was a loose wire to a solenoid that only lost contact while driving but was making contact while testing the system there would be NO HARD FAULT CODE. The code would show up IN MEMORY. The same would happen for a sensor that only went out of range occasionally. Memory codes come out AFTER the separator pulse. The EEC will erase the memory after a certain number of engine re-starts if the problem does not repeat itself. The number of re-starts varies from 20 to 80 depending on the year of the vehicle. The later models keep memory longer. Hard Codes are for issues that the EEC is seeing at the time of the self test. Examples are a sensor out of range or a broken wire (open circuit). Hard Does are the FIRST set of slow codes output in a Key On Engine Off (KOEO) portion, before the seperator pulse. Source: by miesk5 at Ford Bronco Zone Forums Maintenance & Lubrication in a 96 Source: by thedieselstop.com No Crank, No Start, Stops Running, Backfires, Hesitation, Misfires, Knocks or Rattles, Poor Fuel Economy, Idle Problems, or Shifting Problems Diagnostic Worksheet Source: by Ford via Steve83 (Steve, That dirty old truck) at SuperMotors.net No Crank, No Start/Normal Crank; Hard Start/Long Crank; Stalls After Start, Stalls or Quits on Idle; Rolling Idle, Rough Idle; Fast Idle, Diesels; Low Idle Stalls or Quits on Deacceleration; Stalls/Quits on Acceleration or Cruise, Bucks/Jerks, Hesitates/Stumbles, Surges; Runs Rough on Acceleration or Cruise, Misses; Backfires; Surges on Cruise; Lack/Loss of Power; Poor Fuel Economy; Spark Knock Diagnosis & Troubleshooting, Chapter 10, from Ford Fuel Injection and Electronic Engine Control: How to Understand, Service and Modify, 1988-1993; starts at page 211 & shows what components to check first and Self Test procedure Source: by Charles O. Probst via yunost.ru No Crank, Relay Clicks/Buzzes; "...It can click/buzz from several causes:-A weak battery. Not enough juice to crank it once the solenoid closes. Buzz. Bad cables. Look for swollen places in the insulation, white or green dust/corrosion, worn or burnt places, stiff sections, etc. See pic E below. If you replace them, try to get a larger diameter cable. Stock is typically 4 gauge, changing to a 2 or 0 gauge will pay off in the long run. Loose cables. Negative from the battery where it attaches to the engine is a common location, but check them all. Dirty cable connections. Don't just clean the outside, clean where the cable contacts the post & where the other end connects too. Cheap clamp on ends. See pics D & E below. Only good for a trail fix to get you to the store to buy a real cable. -A bad solenoid (Yeah, I said solenoid. Call it a starter relay if you want. I'm old. We've always called it a solenoid, so there. Solenoid, solenoid solenoid). A loose starter that hangs up against the flywheel when it tries to crank. It jams, overloads & drops the voltage. A bad starter. Many auto parts stores will test them. A frozen engine. Serious breakage inside, hydrolocked, rusted solid, badly broken trans keeping the engine from rotating, etc. If you've had both grinding & buzzing, check the starter mounting bolts, since loose bolts can cause both..." Source: by ElKabong (Ken, El Kabong) at FSB No Crank; "...For an engine-won't-crank condition with an automatic transmission (7003), determine if the condition exists with the shift control selector level in both PARK and NEUTRAL positions before performing the ignition switch continuity tests. If the no-crank condition occurs in one shift lever position but not the other, a more probable cause is the Manual Lever Position (MLPS) located on driver's side of transmission case. Ignition Switch Pin-Out Diagram & Continuity Testing (Logic Tables) in a 96; Disconnect ignition key warning switch terminal and wire from the ignition switch (11572). Test the continuity of the ignition switch as described in the following illustrations. Connect a self-powered test lamp or ohmmeter between the blade terminals indicated on the chart. No continuity between any blade and chassis ground should exist in any ignition switch position except the proof Circuit 41 (BK/LB) (Pin P1) and Circuit 512 (T/LG) (Pin P2) in the START position only. NOTE: Ignition Switch Mechanical Test: Accessories that fail to operate with the key in RUN, or that remain on when the key is turned off, may be the result of a misadjusted ignition switch rather than a malfunctioning ignition switch. Refer to Ignition Switch in the Adjustments portion of this section. Do not apply lubricant to the inside of the ignition switch. Test the steering column ignition system mechanical operation by rotating the ignition switch lock cylinder (11582) through all positions of the ignition switch. The movement should feel smooth with no sticking or binding. The ignition system should return from the START position back to the ON position without assistance (spring return). If sticking or binding is encountered, check for the following: burrs on the ignition switch lock cylinder; binding ignition switch lock cylinder; shroud rubbing against ignition switch lock cylinder; burrs or foreign material around the rack-and-pinion actuator in the housing of the ignition switch lock cylinder; insufficient lube on actuator; binding ignition switch..." Source: by thedieselstop.com No Spark Troubleshooting, Overview & Operation in Thick Film Integrated-IV (TFI-IV); "...Ford calls this electronic ignition the Thick Film Integrated-IV (TFI-IV) ignition system. The TFI module is also known as the Ignition Control Module (ICM) which reports engine position and rpm to the PCM. The PCM then determines the proper spark timing and advance, and returns a reference signal to tell the TFI module to switch the coil, thereby creating a spark. The PCM used on these vehicles is referred to by Ford as the Electronic Engine Control-IV (EEC-IV) module..." most is applicable to Broncos, read more; MIESK5 NOTEs; the rotary armature (ARMATURE, also called the Ignition Reluctor) has open areas called windows and tabs called vanes; stator is a Hall Effect device, which uses a magnetic field. It sits under the distributor cap and picks up a signal from the ARMATURE. this armature that has open areas called windows and tabs, called vanes. & ...The ARMATURE has the same number of teeth as cylinders in the engine and moves at the same speed as the distributor and camshaft. If you have a V8 then the ARMATURE has eight teeth; seven teeth are the same and one tooth is smaller to identify cylinder #1. As the ARMATURE spins with the distributor is breaks the magnetic field of the hall device generating a sine wave. This sine wave is called the raw Profile Ignition Pickup (PIP) signal and indicates the engine status at 10deg. BTDC. Now some people think the TFI is responsible for this, but that is incorrect; the PIP signal passes thru the TFI unaltered to the computer...(by Ryan M) Source: by therangerstation.com No Spark. here are a few other symptoms you'll see along with No Spark; The Fuel Pump will still work; None of the Spark Plugs will fire Spark; PCM will still activate the Fuel Injectors Source: by troubleshootmyvehicle.com No Spark. here are a few other symptoms you'll see along with No Spark; The Fuel Pump will still work; None of the Spark Plugs will fire Spark; PCM will still activate the Fuel Injectors Source: by troubleshootmyvehicle.com No Start and or Misfire, etc.; Thick Film Ignition (TFI) Testing, Overview & Diagrams, Black, Computer Controlled Dwell (CCD), Fender Mounted Ignition Control Module (ICM); SEE site for diagrams Source: by easyautodiagnostics.com No Start in 92-96; Starter Relay; "...To test it, bypass it by briding the 2 large posts.If the starter doesn't work, diagnose the starter. If the starter works as it should, but doesn't work using the key, bridge from the rear post (the one with the LARGER cable) to the small (S) post. If the starter works, the relay is good and the fault is between the ignition switch & the relay (clutch switch or neutral switch). If not, the fault is at the relay. If the relay didn't click, either it's not grounded, or its coil is burned out. If it did, its contacts are corroded as the top R pic shows..." Miesk5 Note, check to see if Relay is secure to inner fender or there is rust or grime between inner fender and relay body) Source: by Steve83 (Steve, That dirty old truck) at SuperMotors.net No Start in an 86; "...He turned the key onto crank(nothing happened), reached low on the column, just below the dash, and shoved his pick tool into the column and pulled down. That thing not only rolled over but it started...SO IN CONCLUSION REACH UNDER YOUR DASH AND PULL DOWN ON THAT COLUMN SWITCH ACTUATOR ROD(with the key on) AND SHE'LL LIKELY START RIGHT UP. He told me yes the switches die but they can also "walk" up the column and and get so loose the rod coming down from the key will not actuate the column switch(it's also a sign the $11 switch is about to die)..." Source: by Sixlitre (Malcolm H, Eddie Bauer) at FSB No Start Troubleshooting & Coil Test in a 92; Starter Cranks Engine, but Engine Doesn't Start; see diagrams 4 & 5. Possible Causes: No voltage at TFI Module or Distributor; Bad TFI Module Source: by Seabronc (Rosie, Fred W) at Ford Bronco Zone Forums No Start Troubleshooting; "...First thing to check is wiring. Between the large posts of your starter relay (it's not a solenoid) should be a smaller post with a wire attached. This is the wire from your ignition switch through the Park/Neutral Safety Switch (NSS)/Manual Lever Position Sensor (MLPS), Or clutch safety switch on a manual trans, or NSS/MLPS with an AOD/E4OD, to the starter relay and the on to the starter solenoid (if equipped) and starter. Check this wire for cracks, open insulation, or anything that could possibly cause an open circuit. Next, check your upper ignition actuator. Find the ignition rod (on top of the column, running from the steering wheel down to the ignition switch at the base of the column) and make sure it's moving back and forth when you turn the key, through all positions. If it is, your upper actuator is probably not the problem. Lastly, check your ignition switch (again, at the base of the column). Manually push the switch back and forth through the different positions. Push it all the way forward (or down) and see if it will engage the starter. If it does, then your ignition rod is probably bent, which can be remedied quite easily. & If it's an auto, try starting in neutral or while pulling up on the lever while it's in park. If that works, look to the Park/NSS/MLPS. If it's a stick, check the clutch switch. You could try jumping from hot to the small terminal on the starter relay to test it's operation. Sometimes new ones are bad out of the box. If it won't turn over when jumped to the small terminal, you'll know that it's a starter relay issue (Bad part, bad ground or a bad starter. Check to see if da relay is tight to inner fender with no corrosion because the relay's body is ground path via inner fender). If it does turns over jumped to the small terminal, then you'll be looking for something in the small circuit that includes the ignition switch & the park/neutral safety switch (NSS/MLPS) Or clutch safety switch. There should be 12v running from the ignition switch, thru the NSS/MLPS, to the small terminal on the starter relay. Disconnect the small wire to the starter relay (So it doesn't start by surprise, I'd pull the coil wire too). With someone holding the key in the start position, you should be able to read 12v between any point on that small circuit & ground. When you find where you lose 12v, then you'll know where the issue is..."; MIESK5 EDIT; changed a few terms; Also, see Starter (@) Relay Jumping Image in 92-96 @ /gallery_images/StarterRelayJumpinin92-96.JPG - Sewiw shows a remote start switch's Jumpers; you can use a small jumper; MIESK5 NOTE; from Ford EVTM; The Control Module (PCM) runs the pump{s} for one second when it receives an ignition- on signal. It also runs the pumps as long as it receives a PIP signal from the Hall-effect devices, it continues pump operation even after the key is released from START. If the PIP signals fall below 120RPM, the control module cuts off the signal to the fuel pump relay. The pump will also run when the terminals of the fuel pump test connector are jumped. the Control module signals the pump when it receives a CRANK signal, and when the Control module gets PIP signals that the engine is running. the pump does not run if the PIP indicates the engine is not running even with ignition ON {except for that first one second}. Source: by BigUgly88EB and ElKabong (Ken, El Kabong) at FSB No Start Troubleshooting; "...If you can't start the Bronco from the key/cylinder it might be the upper ignition actuator has broken in it's track inside the steering wheel OR could be just the key cylinder itself which pops out if you look right under it on the metal column collar, there's a little slot and with the key turned to RUN -engine off push up inside with an appropriate tool and comes right out. You can either jump start the vehicle from the "starter relay" under the hood, right inside fender area or pull off the black plastic cosmetic column shroud exposing a long 'ROD" and with the key turned to RUN using a set of pliers, drive the ROD downward/forward and the vehicle will start with most key functions intact....i.e, RUN/NO START, OFF/LOCK, AUX..." Source: by JKossarides ("The Bronco", Jean) at FSB No Start, but Cranks and or Misfire, etc.; Thick Film Ignition (TFI) Testing, Overview & Diagrams; "...This article applies to both the Gray colored Ignition Control Module and the Black colored Ignition Control Module. The Gray colored Ignition Control Module is called the Push Start Module and the Black colored Ignition Control Module is called the Computer Controlled Dwell Module. Part I; In This Fast Test you'll be able to pinpoint the problem to the Ignition Control Module or the Ignition Coil or the Profile Ignition Pickup Sensor (PIP Sensor) in four easy test steps. This test will only help you in a Cranks but Does Not Start Condition. So then, before starting the tests, it's critical that you have checked and verified that there's NO SPARK present at the Ignition Coil. Why? Well, because if the Ignition Coil is sparking, it would be a clear indication that it and the Ignition Coil and the Crankshaft Position Sensor (PIP Sensor) are working. This article applies to both the Gray colored Ignition Control Module and the Black colored Ignition Control Module. The Gray colored Ignition Control Module is called the Push Start Module and the Black colored Ignition Control Module is called the Computer Controlled Dwell Module. These ignition control modules are not interchangeable. If you need the tests for the Ford Fender Mounted Ignition Control Module (ICM), click here. How Does the Ignition Control Module Work? Here's a little background information to help you diagnose this no spark condition. In a nutshell, when the system is working properly, at CRANK-UP and at all engine speeds, the Ignition Control Module controls the Ignition Coil. How? This is primarily done thru' the Profile Ignition Pickup Sensor Signal which is received by the Ignition Control Module (and also the ECM). The Ignition Control Module (ICM) upon receiving this signal, starts switching the Ignition Coil's Ground On and Off. As you may already know, it's this action that makes the Ignition Coil spark away. The Profile Ignition Pickup Sensor signal (more commonly called the PIP Signal) is critical for the Ignition Control Module to start sparking the Ignition Coil at START UP and at all engine speeds. The Profile Ignition Pickup Sensor is a Hall Effect type Crankshaft Position Sensor and produces a digital (On/Off) signal that can be seen with an LED or an oscilloscope. On an oscilloscope, it produces a digital square waveform. This sensor is located in the Distributor. What Tools do I Need for the Ignition Module Test? There are several ways to test this Ignition Control Module. An oscilloscope is the best way to check all of the input and output signals but it's not the only way. I'll show you just how. Anyway, if you have access to an oscilloscope, I have included photos of what the waveforms should look like. Whether you use a multimeter or an Oscilloscope, you'll be able to successfully diagnose this NO START CONDITION! So, here's the basic list: An LED Light. Test Light. Multimeter. A cheapie one will do. Repair Manual. For whatever other information this article does not cover. Helper. To help you crank the engine while you observe the LED light (or Test Light or Multimeter). By the way, you don't need an Automotive Scan Tool for any of these tests. We'll first check for the basics like Battery voltage and Engine Ground to the Ignition Control Module. Then we'll test the Ignition Coil Switching Signal that the Module generates in action and from the results you get you'll be able to pinpoint the problem to the Ignition Control Module (ICM) or the Ignition Coil or the Profile Ignition Pickup (PIP) Sensor or completely eliminate these as the cause of the No Start Condition. IMPORTANT- All of the tests are ON CAR TESTS, do not remove the Ignition Control Module Assembly from the vehicle (all of the figures show the Module Assembly off of the vehicle but this is just for illustration purposes only). Also, the Battery must be in a fully charged condition for all tests in this article. And lastly, this Fast Test only tests for a NO SPARK / No Start Condition. TEST INFO Circuit Descriptions; Here are brief descriptions of the circuits that we'll be testing. You'll notice that there are no wire color descriptions. This is intentional. The color of the wires in the illustration will not match the ones on your vehicle. The good news is that no matter what color the wires are (on the vehicle), the circuit descriptions DO NOT CHANGE. You will be able to successfully diagnose this NO START CONDITION with this information. IMPORTANT- It will be necessary to test some of these circuits while the engine is being cranked. Be careful, use common sense and take all necessary safety precautions. Ignition Control Module Connector; 1- Profile Ignition Pickup (PIP) Signal. 2- Spout. 3- 12 V at START. 4- 12 Volts (gray module) or IDM circuit (black module). 5- Ignition Coil Control Signal. 6- Ground. TEST 1 Checking for Power (12 V); We'll begin by checking that the Ignition Control Module is receiving 12 volts. I recommend using a wire piercing probe to accomplish all of the tests in this article. (click here to see a picture of this tool). Whatever method you use, the key here is to be careful. Remember to use common sense and take all safety precautions . IMPORTANT- The Ignition Coil, Ignition Control Module and the PIP Sensor receive 12 Volts from the same circuit. So if you test one, you test the others. 1 Put the multimeter in VOLTS DC mode. 2 It's not necessary to disconnect the Ignition Control Module (ICM). You'll probe the number 4 circuit of the Ignition Control Module Connector. 3 With the RED multimeter test lead and a suitable tool, probe the number 4 circuit wire of the Connector. 4 With the BLACK lead of the multimeter probe the BATT (-) NEGATIVE terminal. 5 Turn Key On with the Engine Off. Your Multimeter should register 12 Volts DC. CASE 1 If the Multimeter registered 12 Volts DC, All is good in the neighborhood, GO TO TEST 2. CASE 2 If the Multimeter DID NOT register 12 Volts DC, You must find out why you're missing this voltage. Without this voltage the Module, Ignition Coil, and the PIP Sensor will not work. TEST 2 Testing the Ground Circuit; Here we'll check that the Ignition Control Module (ICM) is receiving a good GROUND. This is done thru' the number 6 circuit of the Igntion Module Connector. 1 Put the multimeter in VOLTS DC mode. 2. With the BLACK multimeter test lead and a wire piercing probe, probe the Ignition Module Connector's number 6 circuit wire. 3 With the RED lead of the multimeter probe the BATT (+) POSITIVE terminal. Your Multimeter should register 12 Volts DC. CASE 1 If the Multimeter registered 12 Volts DC, All is good in the neighborhood, GO TO TEST 3. CASE 2 If the Multimeter DID NOT register 12 Volts DC, This means there is open in this circuit. Without this ground the Ignition Module will not function. Repair the circuit. EST 3 Ignition Coil Switching Signal; Now that you have verified the basics, in this test you're gonna' verify that the Ignition Control Module (ICM) is activating the Ignition Coil. Here you're going to use an LED test tool. Click here for a picture of this tool and how to make it. You can also use a Test Light for this test. Use an appropriate tool to pierce the wire and attach the LED test tool (to this tool). Be careful and use all necessary precautions. By the way, in case you want to see a more specific Ford Ignition Coil test, I’ve written one for troubleshootmyvehicle.com and you can see it here: Ford Ignition Coil Test. 1 Connect the RED wire of the LED to the Battery Positive Terminal. 2 Connect the BLACK wire of the LED to the number 5 circuit of the Ignition Control Module Connector 3 Have an assistant crank the engine. the LED test tool (or Test Light) should blink on and off as the engine is being cranked. Did this occur? CASE 1 The LED Light blinked On and Off as the engine was cranking, This means that the Ignition Control Module is triggering the Ignition Coil. So then, the Ignition Control Module is good and can been eliminated as the cause of the NO START condition. By a process of elimination, we can assume that the Ignition Coil is faulty and is the source of the NO START condition. Replace the Ignition Coil. CASE 2 The LED Light DID NOT blink On and Off as the engine was cranking, Re-check all of your connections and retry the test again. If still no light pulses on the test LED, GO TO TEST 4. TEST 4 Testing the PIP Signal; Here we'll check that the Profile Ignition Pickup Sensor (PIP) is being received by the Ignition Control Module (ICM). The PIP Signal is just Ford’s name for the Crankshaft Position Sensor Signal. Now, in case you’re wondering... the PIP Sensor is located inside the Distributor. This will be achieved by using the same LED test tool. Click here for a picture of this LED tool and how to make it. Do not use a Test Light for this test; With a suitable tool and with the key in the Off position, pierce the number 1 circuit wire of the Ignition Control Module Connector. Connect the BLACK wire of LED to the tool that is piercing the wire. Connect the RED wire of the LED to the BATTERY (+) POSITIVE terminal. Have an assistant crank the engine while you observe the LED. The LED should start to blink on and off as the engine is cranked. Is the LED blinking on and off as the engine is cranked? CASE 1 If the LED blinked On and OFF as your helper cranked the engine The Ignition Control Module (ICM) is BAD. Replace the Ignition Control Module. Here’s why: As you’re already aware, the Ignition Control Module needs: 1.) power in the form of 12 Volts. 2.) It needs a good path to ground. 3.) It needs the PIP Signal to start creating the Switching Signal the Ignition Coil needs to start sparking.. So, up until this point (in the testing) you have verified that the module does have power, that it does have ground and that it’s not creating a Switching Signal for the Ignition Coil. In this step you have confirmed that the PIP Sensor is generating a PIP Signal (as indicated by a blinking LED light). So, if the Ign. Module is getting power, ground and the PIP Signal (as evidenced by the blinking LED) is has to create a Switching Signal... if it doesn’t, it’s fried. CASE 2 The LED DID NOT blink On and OFF as your helper cranked the engine If you have no pulses, recheck all connections. Try again. If you still have no pulses. The Profile Ignition Pickup Sensor (PIP) is BAD and the cause of this NO START condition. You’ll need to replace the PIP Sensor to solve the No Start No Spark Condition on your Ford (or Mercury or Lincoln) vehicle. As mentioned earlier, the Profile Ignition Pickup (PIP) Sensor is just a Crankshaft Position Sensor located inside the Distributor. This is the Sensor that tells the Ignition Control Module (ICM) when to start activating the Ignition Coil to start Sparking away. So, if this PIP Signal is missing (as indicated by the LED not blinking on and off), the Ignition Control Module will not function..." SEE Site for Diagrams Source: by easyautodiagnostics.com Repair Locations Grid & Coding, Bronco; used to pin-point location of a repair or component in a vehicle Source: by Ford via Steve83 (Steve, That dirty old truck) at SuperMotors.net Sixlitre Tune-Up Info (scroll through pages to view more tips, especially on Page 5); "...Yes, stock timing is 10 degrees, I find optimum timing to be almost exactly 13.5 but you can play around until you notice ping and then back off 2 degrees if you want to, and/or tune by vacuum if you care to. Cheapest Autolites money can buy, nuthin' platinum, nuthin' fancy, just set out to .055 gap..."; miesk5 Note, Vac Canister info is for vacuum advance distributors Source: by Sixlitre (Malcolm H, Eddie Bauer) at FSB Spark Tester, DIY; W/ an old spark plug and cut off the L-shaped tip,& clean up the center electrode and surrounding metal with a bit of sandpaper. Drill a small hole in the thickest part of the metal (where the wrench goes on). Use a metal screw to attach a length of wire, a couple of feet, to the body of the spark plug. To the other end of the wire, solder or otherwise attach a big alligator clip. Since the tip is cut off, the spark will have to be stronger to jump the wider gap. It is harder for a spark to form in a compressed cylinder so it more accurately represents the spark performance under running conditions. With the engine off, remove the spark plug wire you wish to test from the spark plug. Attach the spark tester to the plug wire and connect the alligator clip to a good ground. Remember that the coil output can give you a very nasty shock, so make sure to wear thick gloves or use a rag to hold the tester, and not to touch the body of the car when the system is energized. Hold the tester away from the car body and use your remote starter switch or have an assistant start the car (or simply turn it over). You should get a healthy bluish white spark from the center post to the side of the spark tester. COIL; If your coil is already off the Bronco, you can bench test your coil. To set up the test, remove one spark plug wire from its plug, then remove the spark plug using a spark plug socket. Next put the spark plug back into the spark plug wire. Be careful not to let anything drop into the empty spark plug hole. Holding the plug wire with insulated pliers, find a spot on the engine that is a good and easily accessible grounding point. Pretty much any exposed metal, including the engine itself, will do. Holding the spark plug wire with your pliers, touch the threaded portion of the spark plug to the grounding point. Have somebody crank the engine with the key, and look for a bright blue spark to jump across the spark plug gap. If you see a nice, bright spark (clearly visible in daylight) your coil is doing its job. Source: by miesk5 at FSB Symbols in Wiring Diagrams Source: by Steve83 (Steve, That dirty old truck) at SuperMotors.net Testing & Servicing, Chapter 11, from Ford Fuel Injection and Electronic Engine Control: How to Understand, Service and Modify, 1988-1993 Source: by Charles O. Probst via yunost.ru Tuning for Performance & Economy, Chapter 9, from Ford Fuel Injection and Electronic Engine Control: How to Understand, Service and Modify, 1988-1993 Source: by Charles O. Probst via yunost.ru Voltage Reference (VREF) is a conditioned regulated constant 5v DC power source supplied by the PCM. Source: by miesk5 at FSB Waterproofing Discussion Source: by members at FSB Waterproofing Discussion #2 Source: by members at FSB Wiring Diagram in an 89 Source: by Seabronc (Rosie, Fred W) at Ford Bronco Zone Forums Wiring Diagrams (Partial, Bronco similar) for F 150 in 86, 89, 91 & 95; EEC, Start/Ignition, EFI/Fuel System, Emissions, E4OD, AOD/C6 (+ clutch interlock switch), etc. Source: by Ryan M (Fireguy50) at oldfuelinjection.com