Starter drag when engine is warm

Johnny Atomic · Friday at 2:00 PM

I'm having an intermittent problem with my truck. When the engine is cold it starts great. But if i try to re-start it after driving 20mins or more, the starter drags then will generally start. One mechanic said it was the battery ground cable. so I replaced the ground cable with a 2 gauge instead of 4 gauge. Problem still exists. Next place I took it tightened and checked connections on starter, did a load test on the starter and said it was fine, and tested the battery and said it was a little weak (4 years old) and replaced the battery. It is still having this problem, one guy there said it was the timing was off, but it is set exactly to specs on the radiator support.

YakkoWarner · Friday at 2:14 PM

Johnny Atomic said:
I'm having an intermittent problem with my truck. When the engine is cold it starts great. But if i try to re-start it after driving 20mins or more, the starter drags then will generally start. One mechanic said it was the battery ground cable. so I replaced the ground cable with a 2 gauge instead of 4 gauge. Problem still exists. Next place I took it tightened and checked connections on started, did a load test on the starter and said it was fine, and tested the battery and said it was a little weak (4 years old) and replaced the battery. It is still having this problem, one guy there said it was the timing was off, but it is set exactly to specs on the radiator support.

My old F250 used to do this exact same thing - crank like mad when cold but I had to park on hills when I went to the store and find a gas pump with a slope away from the fueling position because if you turned it off hot, you'd have a 45 minute wait to get it going again unless you did the old manual transmission roll and clutch bump routine.

In that case it was the starter solenoid relay (which is external on the fords). Seemed to develop higher resistance when hot. On the GM trucks the solenoid is on the starter itself - if you have a way to cool down the starter (while the rest of the engine is hot), that may get you a data point to work from.

Johnny Atomic · Friday at 2:24 PM

YakkoWarner said:
My old F250 used to do this exact same thing - crank like mad when cold but I had to park on hills when I went to the store and find a gas pump with a slope away from the fueling position because if you turned it off hot, you'd have a 45 minute wait to get it going again unless you did the old manual transmission roll and clutch bump routine.

In that case it was the starter solenoid relay (which is external on the fords). Seemed to develop higher resistance when hot. On the GM trucks the solenoid is on the starter itself - if you have a way to cool down the starter (while the rest of the engine is hot), that may get you a data point to work from.

I saw some youtube vids that showed installing a ford external solenoid on SBC for this reason.

fast 99 · Friday at 3:37 PM

Johnny Atomic said:
I saw some youtube vids that showed installing a ford external solenoid on SBC for this reason.

Shouldn't have to modify the vehicle.

If everything checks out, good battery with high enough amperage, clean and tight battery cables [no bolt on ends], all grounds intact and clean, correct timing, suspect a starter. Checking the starter off the vehicle it's not accurate. If that's how it was checked. Should use an amp clamp style meter.

Can use a later permanent magnet style starter with correct mounting bolts.

edit,
FYI there have been issues with Ford style remote offshore solenoids either sticking closed or not working at all, stay away. Some have been scouring pick and pull yards for original Ford parts.

Grit dog · Friday at 5:40 PM

If timing is right, engine healthy and good power to battery, think I’d just replace the starter.
$100 or less and it probably 30 or 40 years old anyways.
JMO.

YakkoWarner · Friday at 6:01 PM

fast 99 said:
Shouldn't have to modify the vehicle.

If everything checks out, good battery with high enough amperage, clean and tight battery cables [no bolt on ends], all grounds intact and clean, correct timing, suspect a starter. Checking the starter off the vehicle it's not accurate. If that's how it was checked. Should use an amp clamp style meter.

Can use a later permanent magnet style starter with correct mounting bolts.

edit,
FYI there have been issues with Ford style remote offshore solenoids either sticking closed or not working at all, stay away. Some have been scouring pick and pull yards for original Ford parts.

Very true - my Jeep uses a ford-style external solenoid and I had an aftermarket one stick "on" - good way to ruin a starter if the engine actually starts and runs.

Starter drag when engine is warm

Johnny Atomic

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YakkoWarner

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Johnny Atomic

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