Erratic Starting Problem

[freedom5]

Still having some problems with occasional starting. It's not fuel pressure bleed down as it can sit for days and will fire right up - run smooth with good acceleration. Occasionally after being driven when attempting a restart it will seem to try but the Bendix will kick out before it runs and starts up after the second or third try. I'm still leaning towards it being caused by the engine temp sensor.

Any other ideas?

Freedom5

 

[RonD]

Reads more like Power/Voltage issue or TFI module.

Cable from Battery to starter relay and then to starter motor, or starter motor itself.
Maybe even Battery

Get a voltage meter
Put it on the battery terminals
A good battery will show 12.3v to 12.8volts
12.2v and lower means battery can only hold 50% charge, so time to replace it.

Unplug the coil wire from distributor, you want a no start
While watching the volt meter have someone try to start the cold engine.
Voltage should drop to about 10volts

Now drive the truck until warmed up, then do the same test, no coil, and watch how far voltage drops, if it gets down to 9volts then there is a voltage issue.

Heat causes higher resistance in wires, higher resistance causes higher amps needed, higher amps needed means higher voltage drop.

When restarting a warmed up engine, all the wiring in the engine bay will be warmer, starter motor will be warmer.
So you will always get more of a voltage drop in the system when restarting, that is normal, but if voltage drops to much, spark will be very weak and starter motor solenoid can't hold gear out against ring gear(as you described).

I would check(remove) the battery cables, Ground cables as well, and make sure all the contacts are clean, at starter relay and starter motor.

Get some electrical tape and a razor knife
On the larger battery cables slice the insulation back a few inches and peel it back, if you see whitish corrosion replace that cable, Ground cables as well.
If cable looks OK tape it up.

TFI modules often become heat sensitive, and cause a no start when warmed up, but that wouldn't explain the starter motor gear kicking back.

ECT(engine coolant temp) sensor would be a long shot at best, and you would have symptoms of stumbling idle when cold or too high of an idle when warmed up, which are not mentioned

 

[alwaysFlOoReD]

Or it could be the "over running clutch drive" aka "bendix". They get old too and give the symptoms you're describing. Fairly cheap part and pretty easy to change out. I'll qualify my statement by saying that the newest starter I've changed a bendix out is 1980's fords.