slow cranking
Posting Guru
Joined: Jun 1999
Posts: 2,404
Likes: 1
From: Everett, Wa
If it cranks fine when cold then I would say its heat soaking the starter. Basic electronics says when heat increases so does resistance. So when your starter is hot it takes more voltage/current to get it to move.
Now things to do in order of cost.
Clean all electrical connections to the starter, starting at the battery. If it is not to hard remove the starter and clean the mating surface of the starter and mount. Another thing to do is clean the ground strap surfaces to the to the engine. This is located towards the back of the engine. If any cables look bad replace them. Doing this will insure that you have the best possible path for current.
If the problem is still there look at the condition of the battery and starter. A weak battery or starter may work fine when cold but cause problems when hot. If either are suspect replace them. If you need to replace the starter I would go with one of the aftermarket high torgue models. They cost more but IMO are well worth it.
Now things to do in order of cost.
Clean all electrical connections to the starter, starting at the battery. If it is not to hard remove the starter and clean the mating surface of the starter and mount. Another thing to do is clean the ground strap surfaces to the to the engine. This is located towards the back of the engine. If any cables look bad replace them. Doing this will insure that you have the best possible path for current.
If the problem is still there look at the condition of the battery and starter. A weak battery or starter may work fine when cold but cause problems when hot. If either are suspect replace them. If you need to replace the starter I would go with one of the aftermarket high torgue models. They cost more but IMO are well worth it.
More Turbo
Joined: Nov 2003
Posts: 748
Likes: 28
Same problem here(79 f250-460/auto).Replaced eveything: all cables,starter deal thing and starter.No more problem.Block to frame cable wasn't there,but when I pulled the starter out it was pretty jacked up.Starter was only 25-30$.
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New User
Joined: Feb 2004
Posts: 10
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thanks for the ifo guys.I was thinking the starter heating up was the problem I've heard that if you wrap the starter in heat resitant tape that would fix it but I'm worried that that could cause problems of there own any ideas on that ...its my sons first truck and I would like to get it running the best i could for him..
FE "Freakin Expensive"
Joined: Dec 2003
Posts: 6,461
Likes: 4
From: Smith Mountain Lake, VA
I run Hedders on my 70 390/C6.... I have had since 72...I put hedders on it 2 weeks after I bought it...and in 2 years i went thru 3 starters that were burned up from hedder heat! I put hedder wrap on the new starter in 74..and it in the truck and in service to this day! Now watch..after I bragged on it... I'll go to start it..and nothing!
Good Luck -Russ
Good Luck -Russ
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Freshman User
Joined: Nov 2003
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From: michigan
For what it's worth I had the same problem on my '94. After a lot of head scratching I finally did what was recommended above and checked out every wire (which isn't really that many.) Found the ground cable from the battery to the engine block was nearly corroded through at the eyelet where it bolts to the block. Replaced the entire negative cable and all's been good for 4 years. . .
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Verdad Gallardo
Posting Guru
Joined: Feb 2002
Posts: 2,404
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From: Cleveland, WI USA
Been there, done that, too. 71 460 ina 78 F150. I've done everything under the sun over the course of 3 years to fix it and finally got it.
Larger battery cables will make a difference.
Heat shield - I'm told it's better to wrap the header instead of the starter, but that's one guy's opinion. I used two pieces of aluminum with fiberglass insulation in between and pop-riveted them together.
I replaced the starter and solenoid twice.
After all was said and done, TIMING was the problem. Once I adjusted that, it starts every time in every condition. Even crawling on the trails in 80 deg weather for hours.
One way to check if it's the timing is to run it until it's hot, turn it off, and try to restart it. If it's slow to turn over, disconnect the coil and try again. If is spins like mad, that's part of the problem. That's what I did and it worked.
Good luck.
Kevin K.
Larger battery cables will make a difference.
Heat shield - I'm told it's better to wrap the header instead of the starter, but that's one guy's opinion. I used two pieces of aluminum with fiberglass insulation in between and pop-riveted them together.
I replaced the starter and solenoid twice.
After all was said and done, TIMING was the problem. Once I adjusted that, it starts every time in every condition. Even crawling on the trails in 80 deg weather for hours.
One way to check if it's the timing is to run it until it's hot, turn it off, and try to restart it. If it's slow to turn over, disconnect the coil and try again. If is spins like mad, that's part of the problem. That's what I did and it worked.
Good luck.
Kevin K.
New User
Joined: Jun 2004
Posts: 4
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From: Ontario, Canada North of Toronto
slow cranking
I had the same problem with my 460.
Although I am running headers, these are wrapped to help dissipate the heat.
I found that I had to replace the ground cable and clean up the contact surfaces and run another ground from the negative post to a clean point on body near the battery.
The only time I had a problem after that, was when I changed out the battery from an 850 to a 750 amp.( and even then it only occurred once)
Other than that, it has been running fine
Although I am running headers, these are wrapped to help dissipate the heat.
I found that I had to replace the ground cable and clean up the contact surfaces and run another ground from the negative post to a clean point on body near the battery.
The only time I had a problem after that, was when I changed out the battery from an 850 to a 750 amp.( and even then it only occurred once)
Other than that, it has been running fine
Elder User
Joined: Jan 2004
Posts: 648
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Sounds like your starter is beginning to go from the heat. It's common on van chassis where there is limited airflow around the engine. The headers don't help.
In this order...
- Good cables with heavy connectors (not the cheapo Wal-Mart replacements)
- Battery with more cranking amps
- One of the new hi-torque gear reduction startes made for vehicles with headers (expensive, but worth it in the long run)
In this order...
- Good cables with heavy connectors (not the cheapo Wal-Mart replacements)
- Battery with more cranking amps
- One of the new hi-torque gear reduction startes made for vehicles with headers (expensive, but worth it in the long run)
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