Starter dropping out early?

[Girth]

1984 C10 6.2 with a 700R4.

Newish to me truck almost left me waiting on a tow truck at work tonight. Still working through it, so haven't spent much time under it, but thinking I might have a starter issue. Never had one do this.

It'd catch and crank, for maybe 1 second.... then drop out. A couple times it wouldn't catch, you'd just hear the starter spin. It's done that "spin/not engage" thing before, intermittently, just enough to be slightly annoying. She's cranky when cold, so of course the first couple times it DID keep turning the engine over, it wouldn't light, or would light and I would let off the pedal like an idiot and it'd die. (glow plugs are on a manual switch, and theres another switch for high idle?) After about 15 attempts, at least 10 of which it would catch but drop out almost immediately..... finally cranked, fired up and got me home.

Weak solenoid maybe? I need to get under there and run through the wiring first. Lotta oil on things. I crawled under the truck at work to just make sure the starter wasn't loose. Seemed solid as can be. There are different styles of starter too? The brace/bracket is in the glove box, but this one looks to be the slightly shorter case, so maybe doesn't use it? Is there one type of starter that's favored, or one to avoid?

Batteries were new this last weekend. Cleaned the cables/connections before I hooked them up, first thing I checked tonight (yep, still tight) and it obviously had enough juice for all those start attempts. Wires/cables on the other end could be nasty of course.... haven't gotten there yet. Previous owner replaced the transmission.... so I figure I better make sure all that is still tight, and peek at the flex plate.

Any ideas, advice, words of wisdom?

 

[PrairieDrifter]

Weak solenoid. I just swap to like a 97 chevy starter. As long as you have the right flexplate tooth count.

 

[mtbadbob]

Weak/bad bendix spring

 

[AuroraGirl]

Weak solenoid. I just swap to like a 97 chevy starter. As long as you have the right flexplate tooth count.

AND
the new proper bolts so the threads dont get ruined, flexplate dont get worn(or flywheel) and starter drive gear stays in good shape, and block doesnt get damaged(In case issues allowed to go on too long)

 

[Ricko1966]

6.2and 6.5 are not the same bolt pattern as the gas engines,they also need a starter brace or they will break the block. Make sure all your bolts are tight,your brackets in place and tight,your connections are clean and tight,and your flexplate doesn't have mangled teeth. After that we can dig deeper. After rereading your post ,I question do you have the wrong starter? Or the wrong brace? Have you already chewed up the flexplate?

 

[PrairieDrifter]

I glanced over the 6.2 part lol. My fault

 

[Ricko1966]

I glanced over the 6.2 part lol. My fault

Nbd,just didn't want O.P. chasing his tail,you weren't the only one chasing him down the vortec starter rabbit hole.

 

[Girth]

6.2and 6.5 are not the same bolt pattern as the gas engines,they also need a starter brace or they will break the block. Make sure all your bolts are tight,your brackets in place and tight,your connections are clean and tight,and your flexplate doesn't have mangled teeth. After that we can dig deeper. After rereading your post ,I question do you have the wrong starter? Or the wrong brace? Have you already chewed up the flexplate?

It’s the OEM bracket, but it’s not installed. Found it in the glove box. I noticed when searching the various parts suppliers last night, it looks like there are two starters listed, and their design varies slightly. One has an ear with the stud on a cast end cap, to attach the bracket. The other does not, and that’s the one that’s installed on the truck. Price seems to be about the same for both…. So no idea.

 

[Girth]

Ok... figured out the difference, 27MT vs 28MT or Direct vs Gear reduction. For this year, the 27 is correct, but the later 28 will work. The 27 is supposed to have a stud for that brace too, so not sure why it's not installed. Apparently they use different braces.... so maybe some pulled a 28 to put this 27 in? No idea. Fun "surprises" with "new" trucks.

We'll find out tomorrow. A reman'd direct drive from NAPA was more than a new build gear reduction.... so had the wife pick me up a 28MT just in case I don't find anything else suspect under there. Time is money around here, so might just load the parts shotgun. lol

Guessing that old direct drive is just tired. Seems some like them better than the gear reduction, but only when they're healthy. Since I had no core with the new starter, I'm gonna hold onto it and see about giving it a quick refresh. Always nice to have spares around.

Napa couldn't find a PN for the bolts though. Go figure. Two seconds on google and a call to Oreilly's, and the wife picked me up a couple of new bolts too. Now.... just pray it's not raining in the morning. Or that both the C10 AND the CJ start, so I can stuff the truck in my little shop.

 

[AuroraGirl]

Ok... figured out the difference, 27MT vs 28MT or Direct vs Gear reduction. For this year, the 27 is correct, but the later 28 will work. The 27 is supposed to have a stud for that brace too, so not sure why it's not installed. Apparently they use different braces.... so maybe some pulled a 28 to put this 27 in? No idea. Fun "surprises" with "new" trucks.

We'll find out tomorrow. A reman'd direct drive from NAPA was more than a new build gear reduction.... so had the wife pick me up a 28MT just in case I don't find anything else suspect under there. Time is money around here, so might just load the parts shotgun. lol

Guessing that old direct drive is just tired. Seems some like them better than the gear reduction, but only when they're healthy. Since I had no core with the new starter, I'm gonna hold onto it and see about giving it a quick refresh. Always nice to have spares around.

Napa couldn't find a PN for the bolts though. Go figure. Two seconds on google and a call to Oreilly's, and the wife picked me up a couple of new bolts too. Now.... just pray it's not raining in the morning. Or that both the C10 AND the CJ start, so I can stuff the truck in my little shop.

im glad you learned this, I knew those starters existed but i had no idea what they were for. Sounds like detroits took them. 28 MT probably is the gear reduction,and thus higher torque?

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Does your starter have that guy on the outside? its an IMS

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I did some searching it appears your starter bolt is 15544950
available new

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these must be plated with stainless because stainless cant be grade 8 or higher

 

[AuroraGirl]

also, be sure if you have a 28mt not to to use a 10 tooth pinion on it unless the housing is special

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what would the difference between a 9 and 10 OEM 28mt be ? no idea, im guessing the larger the pinion drive would be centered based on the picture above but who knows

thought this was interesting:

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[Girth]

im glad you learned this, I knew those starters existed but i had no idea what they were for. Sounds like detroits took them. 28 MT probably is the gear reduction,and thus higher torque?

You must be registered for see images attach

Does your starter have that guy on the outside? its an IMS

You must be registered for see images attach

You must be registered for see images attach

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I did some searching it appears your starter bolt is 15544950
available new

Ok.... so now I'm searching some more. New starter doesn't have that switch off the solenoid, nor does the boss for the solenoid have provisions to mount one like in your pic. Whole ideal with the gear reduction, is it should provide the same torque at a lower draw I thought? If so, I wouldn't think an upgrade in the electrical will be needed.

The PN for the "magnetic switch" in the instructions you posted (1115636) comes back as a 4 post solenoid switch, like a fender mount one, and a 24v one at that? Sounds like something for a CUCV/HMMWV?

It IS a 10 tooth pinion, all the ones I've looked at online are, but it's a closed nose housing too. No idea.

That is the PN for new bolts I found too, and Oreilly's had them. Our local Napa guys.... well, they're kinda special. I really only shop there because they're just down the road, and I do try to support the local shops first. Counter guy was quite literally sniffing my wife's tailpipes yesterday complaining it smelled like her Suburban was running rich. She shrugged and told him it starts/idles/runs just fine...... and if it blows up, she thinks she'll get the Cummins swap she wants anyways. lol

Frost and fog this morning. I'm waiting for the sun to burn it off a bit, then I'll finally suck it up and go crawl under the truck.

 

[AuroraGirl]

Ok.... so now I'm searching some more. New starter doesn't have that switch off the solenoid, nor does the boss for the solenoid have provisions to mount one like in your pic. Whole ideal with the gear reduction, is it should provide the same torque at a lower draw I thought? If so, I wouldn't think an upgrade in the electrical will be needed.

The PN for the "magnetic switch" in the instructions you posted (1115636) comes back as a 4 post solenoid switch, like a fender mount one, and a 24v one at that? Sounds like something for a CUCV/HMMWV?

It IS a 10 tooth pinion, all the ones I've looked at online are, but it's a closed nose housing too. No idea.

That is the PN for new bolts I found too, and Oreilly's had them. Our local Napa guys.... well, they're kinda special. I really only shop there because they're just down the road, and I do try to support the local shops first. Counter guy was quite literally sniffing my wife's tailpipes yesterday complaining it smelled like her Suburban was running rich. She shrugged and told him it starts/idles/runs just fine...... and if it blows up, she thinks she'll get the Cummins swap she wants anyways. lol

Frost and fog this morning. I'm waiting for the sun to burn it off a bit, then I'll finally suck it up and go crawl under the truck.

the draw can be more just depends on the starter, but to confirm you have a 1984 NON cucv truck? yes that solenoid is probably then because of 24 volts setups. I would just verify if your starter pinion and flywheel are showing a lot of wear, if its not, the 10 is probably fine .It sounds like the bulletin i showed you was more to do with different engines (fleet medium duties) which use that starter. and the nose would be different.

Always good idea to check voltage drop on your starter power wire. When the starter is turning, you would determine if there is a large reading on your voltmeter when probing near the battery and near the starter on the same wire in dc volts. If your wire has acceptable readings, you shouldnt need to replace it just clean it up. and check for any chaffing (ive had poor starting due to a power wire that leads to my battery on a ford where it was zapp9ing against sheet metal down low. no idea for how long)

 

[Girth]

Ah... they're talking about the starter relay, with that "magnetic switch". Apparently some were mounted on the starter, some not. Found vague mention of it in the Delco general instructions. Pretty sure I spied one on the fender, next to the GP relay. I'll chase the wiring and confirm.

 

[AuroraGirl]

Ah... they're talking about the starter relay, with that "magnetic switch". Apparently some were mounted on the starter, some not. Found vague mention of it in the Delco general instructions. Pretty sure I spied one on the fender, next to the GP relay. I'll chase the wiring and confirm.

as long as you have one there, youre ok.

EDIT: WELL. to be honest, you may not be ok. if you SHOULD have had a 27mt and you now have a 28mt, and thats an original IMS on your firewall, you may very well want to buy a 1986+ civi IMS
It not supporting the right amount of amps could be poitentially causing your issue, but you would find evidence of heat or arcing or something somewhere