Why does my 1995 f150 4.9 turn over, but not start up?

When troubleshooting an ignition "no-spark" issue, it's helpful to first understand how the system works in sequence. The process starts with the crankshaft position (CKP) sensor detecting engine rotation and cylinder position. The CKP signal is interpreted by the powertrain control module (PCM) which then sends a signal to the ignition control module (ICM). The ICM then drives the ignition coil which is when the high voltage (for spark) is created. From there, the high voltage goes through the ignition coil wire to the center of the distributor cap. Here, the spring-loaded button of the cap touches the center of the spinning rotor and transfers the voltage. The high voltage then jumps from the rotor to whichever pole the rotor is pointed towards at the outer edge of the cap; let's say it's cylinder #1. High voltage then travels through the cylinder #1 ignition wire to the cylinder #1 spark plug where it sparks and ignites the cylinder's air/fuel mixture. Considering these things, if there is no spark from any of the cylinder-specific ignition wires, the issue must be further upstream. Start by unplugging the ignition coil wire where it attaches to the distributor and check for spark; if present, the issue is with the distributor cap or rotor. If not present, the issue is further upstream. ICM and ignition coils are both pretty common failures, but further in-depth diagnosis would need to be performed in order to determine if there is a circuit failure, sensor failure, module failure, or other component failure. You can read more here: https://www.yourmechanic.com/article/how-to-replace-a-distributor-rotor-and-cap-by-tim-charlet

1. The ignition system on your 5.0L uses a distributor type system and will include the following components:
   1. Ignition control module (ICM). Depending on the year of your specific Ford, it'll have a inner-fender mounted ignition control module or a distributor mounted ignition control module. hot sure which you have.
   2. Ignition coil. you replaced it.
   3. PIP (Profile Ignition Pickup) sensor. This is Ford's name for the crank sensor and is mounted inside the distributor. The most common name for this component is the pick up coil.
   4. Distributor cap and rotor. you replaced
   5. Spark plug wires. you replaced.
2. The thing to keep in mind about the ignition system is that all engine cylinders must get spark and the one thing that will stop the ignition system from creating spark on a wholesale scale is a BAD crank sensor.Have you pulled a plug then using some insulated pliers grounded it to the vehicle and turned it over to see if you have spark, that'll tell you alot.takes two people of course.Best of luck and hope this helps.

Check for power to the ignition module. That is the most likely part to fail after the coil.

This diagram is for 1998-1995 Chevy 6 cylinder 4.3L engines.
Your got the firing order exactly correct, at 1-6-5-4-3-2, but here's the thing to double-check:
The distributor rotation is clockwise (note badly rendered arrow in picture).





Since you probably got everything right, then you're left with really unusual/rare causes of
failure of the ignition system:
(a) rotor button misaligned/failing to make contact?
(b) rotor button not pressed onto distributor shaft far enough therefore failing to provide correct
proximity to distributor cap contacts when coil fires
(c) coil wire or contact loose/disconnected - press coil wire firmly down into distributor cap.
(d) distributor shaft of other damage caused during installation of rotor.
(e) spark plug wires defective from factory
(f) spark plugs defective from factory
(g) battery low - may need a charge to start
(h) ICM (ignition control module) failure - hook up your HEI (high energy ignition) tester, and
watch the quality of the spark on each cylinder.
(i) fuel problem? If spark is being properly delivered, its gotta be a fuel problem...
(j) distributor cap not screwed down flush to top of distributor? maybe just on one side?

Inspect the inside of the distributor cap - if there are lots of little metal bits all over the inside
of the distributor cap, then you know you have a misalignment of some type in there, and the
rotor and cap are destroying each other. normal operation will throw a quota of spark-ed off
metal bits inside the distributor cap, but since your cap is brand new, your attempts to start
the engine should have rotated the distributor so few times, you should see no metal debris.

Inspect the distributor cap contacts to see if any spark marks are more of less in the middle
of the cap's proper "contact zone". If not, you've diagnosed an internal misalignment, which
you know how to correct.

then that reduces the possibilities to: bad coil ignition module malfunction distributor failure distributor cap and rotor

Check the starter solenoid, or igintion switch

Hi Friend:

#1) Check your Distributor Cap and Rotor,Cap could be Cracked or Damaged also Rotor.

#2) Since you have 4-coils its possible that 1-or more coils are Damaged,Test each one Individually,to make sure its not a Coil.

#3) Next if All checks out on #1 and #2 ,Then it sounds like your Ignition Control Module Or your Coil Pick-up, Start with your Control Module 1st. Is only held by a couple screws and wire connectors.

#4) Your pick up coil is located below your Distributor cap,The Distributor must be removed to replace it.

#5) If your distributor cap is not Cracked or Terminals Burn't or Carbon Deposits,I would Go Ahead and Replace the Control Module,its only like 30-35.00

This will help you solve your problem, Please let me know how you come out.

Thank You for using FixYa From: d_hubbs

First check to see if full battery voltage is even getting to the "Pos" (+) positive side of the ignition coil when the key is in the "Run" position, and also that full battery voltage is getting through the "Pos" (+) or positive side of the ignition coil and over to the distributor ignition module

The ignition module and the pick-up coil/stator located inside of the distributor is what generates the signal that the ECM (Engine Control Module) uses to time and fire the fuel injectors, as well as the signal to run the fuel pump and the dwell signal timing to fire the ignition coil, and a faulty ignition module can cause any one of these systems to malfunction.

That does sound like a malfunction with the ignition module inside of the distributor, and you can remove the ignition module and have it tested for free at most auto part stores. If the ignition module does test out alright then the problem could still be in the pick-up coil/stator, (it can be tested using an ohm meter by dis-connecting the wire connector from the pick-up coil/stator and the ohm reading between the two wires from the pick-up coil/stator should be between 500 and 1500 ohm's, and both of the wires from the pick-up coil/stator should show an open loop or an infinite reading between each wire and ground) and if the pick-up coil/stator is found to be faulty then replace the entire distributor, or the distributor will have to be dis-assembled to install a new pick-up coil/stator.

If you do purchase a new ignition module be sure that it does come with a silicone grease or a die-electric compound because it is a heat sink and the ignition module will burn up without it.

To install the new ignition module first clean out the mounting surface inside of the distributor. Then completely coat the metal contact surface under the ignition module with a thick coat the silicone grease or die-electric compound and do not leave any of the metal contact surface of the ignition module un-coated with the silicone grease or die-electric compound, and be very careful not to over-tighten the ignition module or it will be damaged.

To replace the distributor follow this procedure;

The ignition timing is not adjusted with a timing light or with the engine running, and to set the ignition timing follow these procedures.

There is a mark or notch on the distributor housing that the rotor should be pointing to when the engine is on top dead center. This "static" timing is all that matters and the computer will be able to control the timing as long as the ignition rotor is in that position when the engine is at top dead center.

Removal;

1. With the engine at top dead center.

2. Look under the distributor cap and find where the number one terminal runs under the distributor cap, and where that position on the distributor cap corresponds with the distributor housing, and it should match up to a mark or a notch on the distributor housing indicating the number one position.

3. With the engine on top dead center the ignition rotor should be pointing to the number one mark or notch that is on the distributor housing, Then make a reference mark of the position that the ignition rotor is pointing to (out on the engine or firewall) and the more precise you mark the position, the easier the installation of the new distributor will be. This will be reference mark #1.

4. Remove the distributor lock down bolt, (the lock down clamp will most likely be attached to the distributor and if so it should not be removed from the distributor) then slowly lift up on the distributor about three inches and note the direction that the ignition rotor turns, and when the ignition rotor stops turning then mark the position that the ignition rotor is pointing to (out on the engine or firewall) and then lift the distributor striaght up and out, and remove the gasket or any left over gasket material from the intake manifold. The more precise you mark the position the easier it will be to install the new distributor and an assistant might be helpful. This will be reference mark #2

Once the distributor has been removed it is important that the engine does not get cranked over by the starter or the crankshaft turned at all, or the reference marks will become useless.

Installation;

Be sure that the new distributor is complete with a new module and that there is a new gasket in place on the distributor.

1. Lower the distributor with gasket down into the distrbutor well and align the ignition rotor with the #2 reference mark and when the distributor gear engages the drive gear on the camshaft then the ignition rotor should turn to the #1 reference mark as the distributor sets all the way back down flush on the intake manifold.

2. Install and tighten the lock down bolt, and If the distributor is properly installed then the ignition rotor should be pointing to the #1 reference mark and the #1 position on the distributor housing with the engine on top dead center.

Replace the distributor cap and connect the spark plug wires, and see if the engine will start, if the engine does start and the check engine light does not come on (assuming that it was not on before) then the distributor is properly installed and there is no further timing requirements.

Let me know if you require any further assistance.

Check your fuses (ECM) and also recheck your wire leads to the coil. Your ICM (ignition control Module) may also be bad, it's located in your distributor under the rotor. You can have that tested also to make sure it's working 100%, there common to go bad from corrosion caused by condensation under the distributor cap.
Thank you for using Fixya and good luck.

95 JEEP WRANGLER 4 CYL

No spark. I have changed out the distributor cap, rotor, wiring from coil to cap, and coil was replaced. I checked the distibutor by turning ignition key and observing the rotor turn. What else can I check. I did not observe a module.