Sluggish starter
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Mountain Pass
Joined: May 2020
Posts: 151
Likes: 16
Sluggish starter
I have a 1985 300il6 fresh rebuild and a C6 fresh rebuild. It started fine, but I had to replace head gasket and starter was wrong one. I replaced the starter and positive and negative cables. Everything is brand new, yet when I try to start it, it just slow grinds. The battery is good, cables and starter are new. I haven't touched anything else, but now I just get a very slow crank when starting. Any ideas why it's doing this? Any help would be appreciated.
Cargo Master
Joined: Jan 2016
Posts: 2,673
Likes: 373
Is the starter new or a rebuild? The rebuilds (which is what you most often get from parts stores) can be hit or miss. Usually have to go online to get a new one but I do that when I have time to wait.
As always, make sure you're actually getting full voltage to the starter. Sometimes the relays go bad.
As always, make sure you're actually getting full voltage to the starter. Sometimes the relays go bad.
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Mountain Pass
Joined: May 2020
Posts: 151
Likes: 16
The engine is a fresh rebuild. The starter is new. I had the engine running, but oil in the water. Changed the head gasket. The 1st new starter I bought was a 9 tooth and I had to exchange it for a 10 tooth starter solenoid. Slow grind, so I put on new cables. Still slow grind. I was gonna test volts when i get home. Electrical is my worst enemy, so I was looking for thoughts before I fork out mors money I don't have that don't fix anything 😆
Tuned
Joined: Aug 2021
Posts: 274
Likes: 63
You might pull the spark plugs and see if the starter spins the engine over faster. If it still just slowly grinds away, likely the starter or maybe something is jammed up in the engine? If it spins fast with the plugs out, I'm still thinking it's the starter.
Have you tried jumper cables from known good battery to the trucks battery? You could also try the known good one with cables direct to the starter, ground the negative on the block and positive to the starter terminal. Make sure your out of gear when you do this, it will spin the starter, no safety's if it's in gear.
Good luck,
Tom
Have you tried jumper cables from known good battery to the trucks battery? You could also try the known good one with cables direct to the starter, ground the negative on the block and positive to the starter terminal. Make sure your out of gear when you do this, it will spin the starter, no safety's if it's in gear.
Good luck,
Tom
FTE Legend
Joined: Nov 2015
Posts: 30,935
Likes: 4,124
From: Angier, NC
As someone said pull the plugs and turn it over by hand how hard is it?
With the plugs installed run the voltage drop test linked here https://www.ford-trucks.com/forums/1...w-starter.html
This test will pin point where the problem is so you dont have to throw the parts cannon at it.
Also you said new cables how are they run?
The 80's trucks with a 300 have the battery + POS to the solenoid and then to the starter.
The battery - NEG side goes to the frame and then to the top starter bolt.
This way all connections are at the starter not to the block that then has to make its way to the starter through the bell housing 2 times.
There is also a 10ga wire from the motor to the firewall so the cab is grounded.
But run the test above
Dave ----
With the plugs installed run the voltage drop test linked here https://www.ford-trucks.com/forums/1...w-starter.html
This test will pin point where the problem is so you dont have to throw the parts cannon at it.
Also you said new cables how are they run?
The 80's trucks with a 300 have the battery + POS to the solenoid and then to the starter.
The battery - NEG side goes to the frame and then to the top starter bolt.
This way all connections are at the starter not to the block that then has to make its way to the starter through the bell housing 2 times.
There is also a 10ga wire from the motor to the firewall so the cab is grounded.
But run the test above
Dave ----
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Mountain Pass
Joined: May 2020
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Thanks Dave, appreciate the advice. Not sure if I'm clear. The motor runs and turns over. I had to put a heavier head gasket on because I went 9 to 1 compression. I changed the 9 tooth starter to a 10 tooth starter. Nothing else has changed besides the new cables. I have had the motor started and running twice. I'm not understanding what changed in the mean time that would make a sluggish start. Although the 9 tooth made a grinding sound, it started the motor. Idk if that clears it up
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Mountain Pass
Joined: May 2020
Posts: 151
Likes: 16
I bought a stock starter for the 1885 block. My dad built a 300 years ago, went 9 to 1 compression and used a stick starter. I didn't know they made High torque starters but I can check. I want to run the power test first. All I did was change the head gasket and starter. The 9 tooth started it just fine
Logistics Pro
Joined: May 2015
Posts: 4,474
Likes: 973
From: Tri Cities, TN
9 -1 compression isn't high enough to require any special starter. The same starter for an 300-6 auto trans also fits many V8's with more compression than that. With a C6 you will have a 164-tooth flex plate 9 tooth pinion. There are two different starters one for a manual and one for an auto. I suggest you remove the starter and take it to the parts house where you bought it, and have it tested and make sure it is for an auto trans.
Also as suggested in other posts make sure your battery is fully charged and in good condition a Ford direct drive starter can and will draw up to 200 amps when engaged and require around 150 amps at cranking speed. They are powerful starters but there is a price to pay for that.
Also as suggested in other posts make sure your battery is fully charged and in good condition a Ford direct drive starter can and will draw up to 200 amps when engaged and require around 150 amps at cranking speed. They are powerful starters but there is a price to pay for that.
Fleet Mechanic
Joined: Dec 2016
Posts: 1,259
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Based on what Cropduster states above, it would seem that the 9 tooth starter that you returned is in fact the correct starter. You also stated that it started fine with the 9 tooth. What made you decide to return it for a 10 tooth? And the cables? What made you change those? I'm in favor of having the new starter tested for sure as most new/rebuilt parts are junk today. So much time is wasted troubleshooting when assuming a "new" part can't be the problem.
Logistics Pro
Joined: May 2015
Posts: 4,474
Likes: 973
From: Tri Cities, TN
If ND was still around, he would straighten us out on all the differences but as far as I know only the 300 HDs in large trucks 500 series and up used a 184-tooth flywheel with a 10-tooth pinion. Also block (index) plates matter if you put the wrong one on nothing lines up correctly. Or worse still forgetting to put the block plate on until after the engine is in and you notice it lying on the workbench. Been there done that, got the "T" shirt.
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Mountain Pass
Joined: May 2020
Posts: 151
Likes: 16
The 9 tooth would grind when starting. It wasn't right. The 10 tooth is smooth, just doesn't want to turn over. After all the replies, i think testing for power is step 1, testing the starter is step 2. It's just baffling to ne hiw changing 2 parts can throw a wrench on the monkey works
Lead Gopher
Joined: Aug 2012
Posts: 10,066
Likes: 1,619
From: Seattle
I just checked my 300 and it uses a 9-tooth pinion. Did you figure out what the grinding was when trying to start before replacing it with a 10 tooth? Maybe a missing block index plate like Crop Duster mentioned? Or a starter for a manual trans where you need one for an auto like Crop Duster also mentioned.
If I go to the online lookups and choose a 1985 Ford 300 in an F150 or F250 (just a guess there) the starters it brings up are all 9 teeth. Might be worth counting the number of teeth on the flywheel/flexplate. If it's 164 like would have been on a 1985 F100 or F250 with 300 then the 9-tooth starter should be correct.
If I go to the online lookups and choose a 1985 Ford 300 in an F150 or F250 (just a guess there) the starters it brings up are all 9 teeth. Might be worth counting the number of teeth on the flywheel/flexplate. If it's 164 like would have been on a 1985 F100 or F250 with 300 then the 9-tooth starter should be correct.