Load on starter when warm

[daven8844x]

This is sort of a repost because I haven't solved the issue, but maybe new info. Having an issue where when I start my '97 K1500 truck after the engine warms, the first turn of the starter sounds hard and slow like it's not gonna turn over. It does turn after the first one and starts. Then if I shut off right away and try again, starter turns fine. It's just that first one. I've replaced the starter and same thing.

I've noticed that the voltage on the battery when I start cold reads (on the gauge) about 16v, but once warm, it settles a tad lower than 14v with nothing but radio pulling power.

I have replaced the positive cable from batt to starter and alternator, I have also replaced the alternator. The battery is new and it happened with the "old" battery too. It seems like a culprit, but I doubt it since it's new and the other one did the same thing. Any ideas I could check?

It's been hard to try and diagnose with voltmeter as it only happens on that first crank.

Thanks in advance!

--Dave

 

[Schurkey]

What is the open-circuit voltage on the battery BEFORE you crank it?

What is the voltage DURING cranking?

Use your meter, don't rely on the dash gauge.

 

[BOOT]

Heat increases resistance. Did you clean the block or ground cable point? Sometimes cables cna look good on the outside but be bad on the inside if you didn't replace the ground. Friend bought a Caddy like that, they couldn't figure it out and he went thru a bunch of the same stuff n all it was is the ground corroded on the inside bad. Actually went thru a bunch of BS myself figuring my project truck out, in the end I cleaned and replaced everything! But each step it got a little better. Made a vlog about it but didn't even get it fully resolved until the next vid LOL never had that much trouble with a starter issue before.

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[daven8844x]

Thanks, I'll check out the video. I did clean and dielectric grease most everything and inspected the ground. It appeared fine, so I did not replace, but maybe I'll just replace, but I did not clean where the ground attaches to the block because I could not get the inner bolt off...but that may have been a wrong tool issue.

I did the voltage drop test. Everything appeared within tolerable range. It is hard, though, to get a good reading on the first turn since it happens quick and the voltmeter jumps around at first.

 

[Schurkey]

I did the voltage drop test. Everything appeared within tolerable range. It is hard, though, to get a good reading on the first turn since it happens quick and the voltmeter jumps around at first.

Describe this "voltage drop" test.

 

[daven8844x]

Describe this "voltage drop" test.

I checked positive VM cable on negative battery post and negative VM cable on starter housing and then also negative VM cable on engine block where the black cable from battery connects. All readings within 0.1-0.2 when I hit the starter. But again, after the first turn, everything seems/sounds fine, so I didn't expect any off readings, and it's hard to capture the first turn reading as the VM jumps around at first when it reads a load.

 

[618 Syndicate]

Are you landing the cable from the battery on the starter and then to the alternator? I found that helped me when I relocated the battery out of the engine compartment.
Also this is what starters do when they start to fail.

 

[Schurkey]

What is the open-circuit voltage on the battery BEFORE you crank it?

What is the voltage DURING cranking?

Use your meter, don't rely on the dash gauge.

I checked positive VM cable on negative battery post and negative VM cable on starter housing and then also negative VM cable on engine block where the black cable from battery connects. All readings within 0.1-0.2 when I hit the starter. But again, after the first turn, everything seems/sounds fine, so I didn't expect any off readings, and it's hard to capture the first turn reading as the VM jumps around at first when it reads a load.

OK, those are genuine voltage-drop tests.

I still want to know about the battery voltage before and during cranking.

 

[daven8844x]

It seems like a wire that is stretching when warm. What is between the ignition and the battery? On the positive side, the cable that goes from battery to starter is new. The battery is new (and has been tested today as good). The starter is new (and has been tested today as good). Then a wire goes from the battery to the alternator...not sure that would be in play at all in this process. Then a wire goes from battery to the fuse box under the hood where the start relay is. That is original and could be a culprit? Then I presume there is a wire from the starter relay in the fuse box to the starter switch (is this the purple wire on the starter?). Is that it? Is there a way to test these two wires?

On the ground side, is it just ground cable to engine block, and the starter is grounded by bolting to the engine block? This is the other original cable. It looks fine, but theoretically could be damaged on the inside.

Thoughts? Thanks so much for all of your help.

 

[Schurkey]

It seems like a wire that is stretching when warm.

Not likely.

What is between the ignition and the battery?

Nothing that matters, if the starter cranks when you turn the key.

The battery is new (and has been tested today as good).

How was it tested? Is it fully-charged?

The starter is new (and has been tested today as good).

How was it tested? What was the amperage draw when cranking the engine?

Then a wire goes from the battery to the alternator...not sure that would be in play at all in this process.

If the alternator keeps the battery charged, it doesn't "play at all in this process."

Then a wire goes from battery to the fuse box under the hood where the start relay is. That is original and could be a culprit? Then I presume there is a wire from the starter relay in the fuse box to the starter switch (is this the purple wire on the starter?). Is that it? Is there a way to test these two wires?

If you turn the key to "Crank" and the starter cranks reliably...they're fine. You haven't complained about the starter refusing to crank, just that it cranks slowly for awhile.

On the ground side, is it just ground cable to engine block, and the starter is grounded by bolting to the engine block?

Yes. There's other grounds, but in terms of the starter motor cranking speed, those are the important ones.

This is the other original cable. It looks fine, but theoretically could be damaged on the inside.

Your voltage-drop testing shows the ground cable to be fine.

I still want to know about the battery voltage before and during cranking.

...and the amperage draw of the starter when cranking.






Just for giggles, have you tried cranking the engine with the serpentine belt removed? Possible you've got a failed alternator or PS or A/C compressor bearing that's stiff on initial movement. (Not likely, but worth popping the belt off to check.)