Slow cranking when hot
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I removed the fuel pump relay. Put one lead of meter to the positive battery post, and the other lead to the other end of the cable at the starter. Set meter to min/max and cranked the starter. Then did the same with the ground
Logistics Pro
Joined: Jan 2001
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From: Central NYS
When its hot and cranking hard, how low does a volt meter across the battery terminals read?
BTW, both of your voltage drop readings are about double what they should be.
But with the same readings weather hot or cold, I can't explain why it cranks okay cold and not okay hot.
If I had a set of heavy jumper cables, I'd run one cable from the engine block to the B negative connection and one from the battery + terminal to the starter motor connection (effectively double up the existing battery cables) and see if that makes a difference.
BTW, both of your voltage drop readings are about double what they should be.
But with the same readings weather hot or cold, I can't explain why it cranks okay cold and not okay hot.
If I had a set of heavy jumper cables, I'd run one cable from the engine block to the B negative connection and one from the battery + terminal to the starter motor connection (effectively double up the existing battery cables) and see if that makes a difference.
Fleet Mechanic
Joined: Nov 2011
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From: Land of Taxes
Are these readings in amps, ohms or volts? What setting was the meter on?
Again did you pull and inspect ALL of the connections in the starting circuit?
Maybe we need to back up a bit and not eliminate the starter or battery. Are you sure you got a new starter? Take a look at it. Its not uncommon to get a bad new or reman unit out of the box. Same thing for a battery. Load test the battery hot. Does the 08 have a slave relay in line with the starter? If so look at it hot vs cold.
Load test the new starter. Which means removal and bench testing the amp draw.
Again did you pull and inspect ALL of the connections in the starting circuit?
Maybe we need to back up a bit and not eliminate the starter or battery. Are you sure you got a new starter? Take a look at it. Its not uncommon to get a bad new or reman unit out of the box. Same thing for a battery. Load test the battery hot. Does the 08 have a slave relay in line with the starter? If so look at it hot vs cold.
Load test the new starter. Which means removal and bench testing the amp draw.
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I am reading volts on the meter. I talked to the ford dealership this morning. He wants the truck back so they can check the starter. I asked what the maximum allowable voltage drop is, and he said he would have to look Into it. I feel they are getting fed up with my truck because they can't figure it out, and are loosing money on it. The starter is stamped remanufactured
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Logistics Pro
Joined: Jan 2001
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From: Central NYS
Typically, you want to see less than 0.2 volts dropped on the ground side and less that 0.5 volts dropped on the power side.
Does the positive battery pass near the exhaust pipe or exhaust manifold where the cable would get hot? Heat will increase the voltage drop.
Oh, wait! You said that the voltage drops were nearly identical between hot and cold starts.
Is there anything that they could have done that would put a drag on the engine when hot starting? A/C compressor hanging up? Or an Idler pulley seizing? Might try taking the belt off and try a hot start?
Does the positive battery pass near the exhaust pipe or exhaust manifold where the cable would get hot? Heat will increase the voltage drop.
Oh, wait! You said that the voltage drops were nearly identical between hot and cold starts.
Is there anything that they could have done that would put a drag on the engine when hot starting? A/C compressor hanging up? Or an Idler pulley seizing? Might try taking the belt off and try a hot start?
Fleet Mechanic
Joined: Nov 2011
Posts: 1,825
Likes: 43
From: Land of Taxes
I just replaced a "brandie new" NAPA starter in a 99 7.3. The starter was totally locked up. It had about 2K miles on it. Had to hit it with a hammer on the bench with a D8 battery hooked to it just to get it to groan. Of course I couldn't get those dam philips head screws loose to pop off the solenoid for investigative purposes. philips heads really!
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