Ok guys heres the issue. Was driving my truck home on my lunch break friday and it all the sudden died while I was driving it like I turned the key off. However as fast as it died it came back to life and ran without issue. It did this 3 more times until I got home which is when the truck just died completely and didnt want to restart (battery sounded half dead and cranked slowly). I got it started and brought it in the driveway where it sat until today. This morning I replaced the starter because the old one was going bad and would remain engaged while the engine is running. So I swapped it out and all was well. Now I tried to start the truck and...it just cranks. It smells like gas and my fuel filter is full (of gas), so its getting fuel. Any idea why its cranking but not starting? Cranks at normal speed so the battery isnt dead. Im guessing my brain box i dead but before I go throw $35 at it (for the second time), anyone else have any thoughts? Newer coil, newer plugs, new wires, new distributor, etc. Sounds like a brain box to me...just would like some second opinions.

 

Could be a short somewhere. I had similar problems and found bad connection at the ignition coil connector.

 

Sounds like your next step is to check for spark.

 

Yup I'll check it tomorrow morning when it isnt 12 degrees outside

 

i will throw this out to you, Only because this is what happened to me and drove me CRAZY
until i asked and someone Helped me out on this Forum. I have a 77 supercab w/351M and
it would run and like someone just reached over and shut the ignition off it would die.But would start right back up Turned out it was the Factory plastic coil wire clip that connected
the + & - wire's to the Coil. it was suggested to me to take the wire's out of the plastic housing and wire them to the coil without the plastic housing and it ran perfect ever since i did this. it was driving me crazy and was KILLING my pocket book until i did this.
Good Luck!
Allen

 

X2 for what fmc said.

 

I do not think this is not a sign of the starter itself going bad, but a sign of a bad starter solenoid (on the R/H inner fender well) not on the starter itself, I do believe?

Or a bad tumbler in the ignition switch. Yes sounds like it wire and connector checking time. Follow FMC400's advice you will be up and running.

Az58cameo good advice and tip on the coil connector.

 

ok i just checked and Im not getting spark. I replaced my module with one I had laying around and repaired the spade connectors at the coil and I have nothing.

solenoid should be good though I would think because the starter activates fine...right? i may be mistaken here.

Whats funny is that Ive been driving it for months now without issue. It only began acting up friday which i when it died.

 

Next step: with the coil connected, connect a test light between the negative terminal of the coil (TACH TEST) and clean, unpainted metal on the engine (ground). Crank the engine with the key, and the light should BLINK. Report your results.

 

my light stayed solid while I was cranking it

 

That means the module is not switching the coil. Next, please disconnect the ignition module and knock out the following tests:

1) The RED wire in the 2-terminal connector coming from the truck should have 12 volts with the key in START. Note that this wire likely goes to the WHITE wire of the module.

2) The WHITE wire in the 2-terminal connector coming from the truck should have 12 volts with the key in RUN. Note that this wire likely goes to the RED wire of the module.

3) The resistance between the ORANGE and PURPLE wires in the 4-terminal connector coming from the truck should be between 400 and 700 ohms.

4) Neither the ORANGE or PURPLE wires in the 4-terminal connector coming from the truck should have any continuity against ground.

5) The BLACK wire in the 4-terminal connector coming from the truck should have perfect continuity with ground.

6) The GREEN wire in the 4-terminal connector coming from the truck should have 12 volts with the key in RUN or START (this is an unloaded measurement of power back-fed through the coil primary winding). This test is only meaningful with the module disconnected.

If you don't have a multimeter, you need to get one to perform these tests. In cases where you need to probe a female connector and your meter probes won't fit, try making the connection with a paperclip, being careful not to damage the inside of the connector.

Report your results. Your response should consist of three voltage measurements and three resistance measurements.

 

sorry I had a faulty test light for that last test...used my new test light and it flashes while performing the tach test.

 

How does a defective test light come on solid in the first place? The test light itself has no concept of whether it should be blinking or not. If it comes on at all, it's fine. Sounds like user error, or the problem is intermittent. Are you confident that your observations are consistent (as in, the test light really does flash, each time you try)?

Whatever the case may be, if the test light is flashing at all, then the entire primary side of the ignition system is working properly. If you're truly not getting spark, the problem is on the secondary side. That points to cap, rotor, wires, or plug gap.

It's rare for the test light to flash but you not actually have spark. How are you checking for spark?

 

The light had a short in the wires (I've got a + lead, a - lead, and the probe portion). My new test light blinks like its supposed to. I did the tach test 3 times, all of which the light blinked correctly. I am checking for spark by pulling the wire off the distributor cap and holding it above the AC bracket while someone cranks the key.

 

If the primary side IS functioning (as determined by the test light blinking), yet the secondary side IS NOT functioning (as determined by the hand spark test), then the problem is isolated to the cap, rotor, wires, or plugs. On rare occasions, the coil secondary winding is open circuit.