94 Chevy k1500 blazer won’t crank

[Tena90710]

Hi guys I have a 94 full size blazer 350 tbi and I’ve been having this issue when I start it in the morning it turns on good then if I drive it for more than 30 minutes and turn it off and try and start it again it won’t crank or anything my dash lights come on and everything is this a battery problem or the starter

 

[texas tough]

next time it does it, turn on the headlights and see how bright they are
the only way it would be the starter is if the bendix arm is staying engaged. highly doubt that.
check your engine ground from the battery to the block,.,. some are grounded to the aluminum assesory bracket on the front. I always relocate my ground to the block itself.. I also run a heavy ground cable so it has a good ground. if you have a loose ground, when the engine gets hot, it may not be making contact.

 

[Schurkey]

Starter heat-soak problems are common. More-common on engines that have headers rather than iron exhaust manifolds.

Two "typical" issues:
1. Corroded wire harness from battery to ignition switch, switch to starter "S" terminal. Low voltage at the "S" terminal doesn't engage the solenoid, which doesn't engage the starter motor. Symptom includes no "click" from solenoid. If you're lucky, you have one location in the harness with a lot of excess resistance. If you're not lucky, you have multiple places each with a little excess resistance. The wire leading to the "S" terminal is usually purple (fades to pink over time) and is often corroded in the final foot before the solenoid--the wire gets road splash from the wheels, or kicked-up by the car ahead. The wire will turn black inside the insulation. (Even the "good" end of this wire is too corroded to save. I had to replace ~3 feet of wire to get to an accessible part of the wire harness that had clean copper.)

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2. Excess heat in the starter/solenoid increases resistance and mechanical drag. The increased resistance reduces current flow, starter may not engage or has little power. Solenoid may or may not "click".

Verify by performing voltage-drop test, and measure amperage on solenoid "S" terminal when key is turned to "Crank". Low voltage indicates wire harness problem, low amperage indicates wire harness or starter solenoid problem.

Measuring the amperage drawn by the starter motor from the main (heavy) battery cable can also yield clues--high amperage indicates a failing starter motor, low amperage indicates excess resistance in the motor windings; or poor contact at the brushes/armature.

There are other possible causes...but these two are each really common.

"Most" folks treat a failing solenoid or a failing motor the same way--they install a "new" or "rebuild" starter/solenoid combination.

A "quick fix" for a corroded wire harness is to install a "Ford Solenoid" on the fender. There's instructions and even "kits" available on the Internet. However, this does not work well with the Permanent Magnet Gear Reduction (PMGR) "Mini-Starters". Mini-starters tend to not disengage properly when used with the "Ford Solenoid" modification.

 

[PEIslander]

I'm having the same issue with my 94 3500 5.7 truck. New starter/solenoid. Took it out today. Started fine, went to the dump to drop off a bunch of crap and the truck wouldn't start on the scales going out. Not even a click. Checked my connections and they looked ok. Had to get a push off the scales. 5 minutes later it started fine. I suspect heat soak. Would a header wrap around the starter help things? Would a bad wire to the solenoid only present itself when the starter is hot?

 

[Schurkey]

the truck wouldn't start on the scales going out. Not even a click.

Typical of heat-soak. Solenoid won't engage, so starter doesn't crank.

Generally due to corroded wires or connections--the voltage at the starter solenoid "S" terminal is too low to develop enough electro-magnetic effect to pull the solenoid plunger when hot.

Checked my connections and they looked ok.

Test for voltage at the "S" terminal when the key is turned to "Crank".

5 minutes later it started fine. I suspect heat soak.

I suppose. Heat soak generally takes longer than 5 minutes before the starter works again.

Would a header wrap around the starter help things?

Maybe. Downside is that when wrapping the starter with insulation, it takes longer for the starter to cool after use.

I prefer a metal heat-shield that has an air-gap between it and the starter. Keeps heat off the starter, allows heat from the starter to escape.

Would a bad wire to the solenoid only present itself when the starter is hot?

Yup. Corroded wires, corroded connections can have higher resistance when hot.