1988 F350 460

Usually the starter will spin very fast as if everything is perfect. Then sometimes (usually after having run for a little while), it's start off by spinning very slow, as if a 1/2 dead battery. Last night it very nearly didn't get it started. This is a quick starting engine. When I got home, I tried to start it again as a test, it failed to start the truck. Charged up the battery and it was fine.

Pulled the 3 battery cables:
1. battery + to solenoid
2. solenoid to starter
3. battery - to frame and alternator bracket

Pulled the alternator (G3 upgrade from 90's) and starter for testing. Both passed the tests.

Bought and installed new battery terminals, cut off dirty ends and wire brushed the wires to make sure all the connections are clean.

I'm going to do a voltage drop test on the cables, they look good but you never know.

Given that this happened once in maybe 5~8 starts. Sometimes it comes back to life after about 5~8 seconds of cranking slow.

Q1. Does this sound like a ground problem to the starter?

Q2. Is there an advantage/disadvantage to having a direct ground to the starter? I do that on my 73 F250.

Q3. I had the ground go from battery to frame to the alternator bracket, that doesn't seem right, is there an engine grounding bolt or does it really matter?

Q4. do extra ground straps hurt anything?

 

I'm going to go out on a limb here and say your starter might be starting to go. When you said usually after it's been running the heat sounds like it might be getting to it. Also, does the engine leak oil? And if so, is the starter covered in oil?

 

I just pulled the starter and had it tested and it passed. It was very clean, no oil and the truck really doesn't have any leaks.

However, it could still be heat soak. I don't have headers but maybe a heat shield would help.

This is an autolite starter on a stock 460, are they known for heat soaking?

One other note is that after charging up the battery, it goes back to fast starts, but charging the battery would also allow the starter to cool.

 

There's no particular brand that is prone to that (at least not to my knowledge) and all can be prone to heat soaking. Do you live somewhere where it's hot? Possible it might be a loose connection somewhere as well but where exactly I could not say for sure and doubt that's the problem. I would go through and check all your grounds again and make sure they're good and clean to be safe. I'm no expert when it comes to this but that's my 2 cents.

 

I thought Autolite was Ford, but just checked... Ford sold Autolite back in 73 and now they have MotorCraft. I'd still like to think that Autolite is a better brand than average.

Yes, I like in a hot, central valley city in California, however this was a pretty cool evening when it happened.

It's about $80 to replace all the battery/starter cables, quite a jump in the last few years... but I'm going to clean and reinstall things and see what happens before I do that.

At this point, it's either heat soak or battery cables, bad ground...

 

Update. Cleaned up the frame ground and replaced the battery terminal with new one. Cleaned up every contact point and the bolts that go into the block. In about 20 tries, it only turned slow once and then it sped up in about 1/2 the time it did before... so it did improve things.

I did some reading about heat soak and it looks like it is an issue. So I'm going to see what I can do about that. Maybe a fan directly blowing on the starter and something to block heat.

 

If you look around they make these heat resistant shields that wrap around the starter to protect it. They also make a few other things I think but where you can find these I can not say for sure. I'd imagine stuff like this is readily available at a local parts store.

 

Voltage drop test. It's too easy not to do.

Looks can tell you it's bad, but it can't tell you it's good.

 

Mine did that years ago. I replaced the starter with a lifetime warranty from O'Reilly. I went thru 3 of them before I asked for my money back. I then bought a gear-reduction starter from DB Electrical. I also bought a spare since they are mail order only, but it's still in my toolbox because the first one I got is still going great. I buy only their starters now.

 

The lifetime warranty on any of those house brands are pretty much junk. It's bad enough that the original part failed/wore out, but replacing the new part every other month gets really old.