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7.3 diesel start problem

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Old Jan 2, 2025 | 04:20 PM
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Angry 7.3 diesel start problem

Two new batteries, used 3 or 4 times parked it, No problems 2 weeks later try to start glow plugs etc turned key nothing 2 more times a hell of electrical smell (Starter). A few days later Batteries check .97 volts Negative .68 on the other under removed starter. The brass flat between solenoid and starter 1/4 to 1/2 inch burned gap. Warrantied batteries luckily. New starter. Batteries at 12.8 both. All fuses checked and good both in cab and in engine bay. Don't know how to check relays. I have everything in truck working radio blower lights etc. Turn key on glow plug light comes on goes out ignition Nothing. Its like there is no connection between key and starter. Can someone help me with this. I have all my owners etc manuals. There has to be something else that has blown. I am in Fl so theres no cold problems Truck has run flawlessly till now HELP Skip My email included just in case Nelsonarthure@aol.com
 
Old Jan 3, 2025 | 04:51 AM
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What was the condition of the starter and solenoid when you removed the starter. By condition..........was paint burned off the solenoid or starter ? Only a direct short right at the solenoid could do that OR excessive cranking attempting to start the engine. Could this maybe be an operator problem ?
 
Old Jan 3, 2025 | 06:10 AM
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Originally Posted by hanky
What was the condition of the starter and solenoid when you removed the starter. By condition..........was paint burned off the solenoid or starter ? Only a direct short right at the solenoid could do that OR excessive cranking attempting to start the engine. Could this maybe be an operator problem ?
The truck ran fine. When I pulled the starter the link between solenoid and the starter was completely burned through. Today I will pull see if there is voltage on solenoid while my helper turns the key to start position. Buddy has recommended pulling new starter and bench test to make sure starter is good. There is a code alarm in the truck but I never used it. To start the truck I would always have to push the bypass button to start the truck. I have been unable to do this now also. I was wondering if there might be a relay that the starting circuit goes through?? Thanks for the response. There was definately alot of draw by starter. And as far as an operator problem aanything possible but I have had this truck since 5ooo miiles and I am at 165000 now but I am getting older also LOL Thanks Skip
 

Last edited by countach1; Jan 3, 2025 at 06:13 AM. Reason: addition of results
Old Jan 3, 2025 | 06:16 AM
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After I tried to start it and it didn't. No Crank I tried it again 2 o3 times for seconds. After a few days the batteries were dead so Nothing happened nothing truck wide no lights etc. So I am rulling out the overcranking.. The truck fired right up all the time
 
Old Jan 3, 2025 | 07:14 AM
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One of the checks you might do,,,,,,,,,,,,,when you first turn the key on, do you have power going to the glow plugs ?

There is a glow plug relay located at the top rear of the engine. Check if that is working.

The starters on those engines from my experience gave very little trouble and didn't require replacement that often.
Something had to keep that solenoid on the starter energized a long time to burn the link from the solenoid to the starter motor to the point where it melted.
 

Last edited by hanky; Jan 3, 2025 at 07:22 AM.
Old Jan 3, 2025 | 10:42 AM
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So I have the same no start but I have located the starter solenoid on the passenger side fender well. If I turn the key to the on position and short the poles on the relay the motor spins like hell but doesnt start. If I turn the key off and cross the poles the starter spins like heck but doesnt start. I flipped relays in the hood compartment same result. There is something not alllowing the starter relay to send current to the starter. By shorting the relay it spins HELP Thanks for all of thiss Skip
 
Old Jan 3, 2025 | 11:31 AM
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The dash board shows the glow plugs timing. I just now cut the alarm system from the truck and I know longer get the glow plugg light on the dash no start but crossing lugs to starter relay spins engine over but no start I am going to take 5 for a minute on this one
 
Old Jan 3, 2025 | 03:48 PM
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Somebody had to interrupt power to fuel syst for the by pass to work. just cutting stuff off/out adds to the problem.Without being there to see just what is what limits what to suggest. Too many fingers in the pie don't help.

What year is your truck
 

Last edited by hanky; Jan 3, 2025 at 03:59 PM.
Old Jan 4, 2025 | 05:11 PM
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So update: Got it all back as it was the first day. Went through all fuses with continuity tester. Had 2 blown?! The dedicated starter solenoid on the fender well was not working. Motorcraft F5TU-11450-AA 3 pole. Advance says this one fits my vehicle Carquest SBC2106 $ poles. Two terminals are marked S and I They said to use one but didn't know which pole. I used the S pole and the truck fired right up but now my battery light stays on. Any help would greatly appreciated as your help has gotten me to this point. Or is there a part number that mightbe the right one or ??? Help Thanks Skip
 
Old Jan 4, 2025 | 05:27 PM
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If the meter you are using can measure "DC Volts", black lead to battery negative post and red lead to battery positive post. The reading you get there will tell us if the alt is charging or not. What year is your truck?
Different problems can cause the battery lite to illuminate, so we need to eliminate causes one at a time.
Can you do this ? Thanks.
 



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