1999 K2500 Suburban 7.4 - no crank

[TexasAggie]

Howdy folks -

I put a new battery in the Suburban Saturday morning as the old one was woefully undersized (previous owner cheaped out). Got it installed and she fired up strong. After driving it around all day (probably started it a dozen times) I went out to move it in the driveway and I turned the key and nothing happened. All systems came on, but no crank. No clicking, no noises, nothing. Radio turned off like it normally does when cranking, but nothing from the starter. I was dumbfounded so just kept trying it and after ten or so tries, she fired up. Moved it, turned it off, and started it again with no issues. Drove it around all day Sunday with no issues. Go out this morning and no crank. I pulled the cables off to make sure the starter cable had good connection and didn't see any issues there. Put them back on and still nothing.

Next step in keeping it simple would be the starter. Is this how they act when a solenoid goes out? I've only ever had one starter go out on me and it acted up for a month or so before I got around to replacing it. This is the first time in a year of ownership that I've had any trouble with this one.

Any tips other than to replace the starter?

 

[stutaeng]

Could be starter, yes. Get yourself a test light with some test leads and hook it up to the starter to confirm the starter solenoid is seeing power when you crank.

Or, tap the starter with a hammer when it does it. If it starts after the tap, starter is most likely the problem.

Also double check the starter relay in the fuse block is okay and making good contact. My K3500 will sometimes do the no-crank like yours and wiggling the the relay takes care of it...

 

[TexasAggie]

Good call on the relay. I didn't think about that at 4:30 this morning. I'll open up the fuse panel and figure out which one it is when I get home today.

 

[stutaeng]

The tapping with the hammer is really a 2 man job. One guy underneath and another hitting the key...good luck.

 

[TexasAggie]

No luck on the relay. I swapped it out with another in the fuse block and same issue. I'll get the test light out tomorrow and see what I can find out.

 

[Schurkey]

You'd want to test for voltage at the "S" terminal when using the test light. The test light better be VERY bright when cranking.

If the light is dull, you've got low voltage there. A voltmeter does a better job of quantifying power availability than the test light. If that voltmeter has min/max/avg feature, you can do the testing with one person--just look for the max voltage after turning the key. "Min" voltage will be "0", and average voltage isn't important.

 

[TexasAggie]

That's good to know because I wasn't sure how exactly to test it. What do the results mean either way?

 

[Schurkey]

That's good to know because I wasn't sure how exactly to test it. What do the results mean either way?

Bright light = high voltage = good power to the "S" terminal. If the starter fails to crank, it's almost certainly a genuine starter/solenoid problem.

Dim light = low voltage = crappy power to the "S" terminal. If the starter fails to crank, it's likely a problem with the wire connected to the "S" terminal; the relay in the electrical center, the neutral-safety switch, or the ignition switch. Leave the wire connected to the "S" terminal, trace the power backwards through the system until you have good voltage. This MIGHT be an issue with several somewhat-corroded connections rather than one heavily-corroded connection.

Crappy power to the "S" terminal may not activate the solenoid = no cranking, especially when the starter motor is hot. If the starter cranks SLOWLY, that's an entirely different diagnostic procedure.

The wire connecting to the "S" terminal is often corroded due to road splash. Mine had corroded more than a foot up the insulation; I couldn't cut it back far enough to get to "clean" copper and still have enough access to the harness to solder-in an extension. I had to go up on top of the engine and solder-in about three feet of fresh, clean wire.

Previous repair done by former owner...which corroded again.

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Section of wire I cut out that used to be connected to the white wire above. "Purple" is the original color of this wire's insulation. Note that even the "good" end is too corroded to use.

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...but I didn't have purple wire in 12-gauge; and neither did the local parts stores. Therefore, I spliced-in red wire, and routed it down to the starter. Splice is crimped, then soldered, then covered in heat-shrink tubing that has adhesive on the inside for absolute weather protection.

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[TexasAggie]

I had a nice bright light when turning the key, so $100 and a trip to O'Reilly and she's back up and running. I wasn't able to get the factory heat shield off of the original starter because I don't have the star sockets. Is it really necessary? Either way, I'm going to try and get it off somehow before I return the core and stick in my pile of spare parts just in case.

 

[454cid]

I had a nice bright light when turning the key, so $100 and a trip to O'Reilly and she's back up and running. I wasn't able to get the factory heat shield off of the original starter because I don't have the star sockets. Is it really necessary? Either way, I'm going to try and get it off somehow before I return the core and stick in my pile of spare parts just in case.

I think I used a hex socket just the right size.