diagnose the starting system
DESCRIPTION
Diagnose the Starting System. Fender Covers !. You must have a strong battery to test the starter. Test the Starter Circuit. Cranking Voltage Cranking R. P. M. Cranking Amps. Move Amp Probe to measure all amps leaving battery. Disable Fuel System. - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: Diagnose the Starting System](https://reader035.vdocuments.site/reader035/viewer/2022081502/56815be6550346895dc9daad/html5/thumbnails/1.jpg)
Diagnose the Starting System
![Page 2: Diagnose the Starting System](https://reader035.vdocuments.site/reader035/viewer/2022081502/56815be6550346895dc9daad/html5/thumbnails/2.jpg)
Fender Covers !
![Page 3: Diagnose the Starting System](https://reader035.vdocuments.site/reader035/viewer/2022081502/56815be6550346895dc9daad/html5/thumbnails/3.jpg)
You must have a strong battery to test the starter
![Page 4: Diagnose the Starting System](https://reader035.vdocuments.site/reader035/viewer/2022081502/56815be6550346895dc9daad/html5/thumbnails/4.jpg)
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Test the Starter Circuit
• Cranking Voltage
• Cranking R. P. M.
• Cranking Amps
![Page 6: Diagnose the Starting System](https://reader035.vdocuments.site/reader035/viewer/2022081502/56815be6550346895dc9daad/html5/thumbnails/6.jpg)
Move Amp Probeto measure all amps leaving battery
![Page 7: Diagnose the Starting System](https://reader035.vdocuments.site/reader035/viewer/2022081502/56815be6550346895dc9daad/html5/thumbnails/7.jpg)
Disable Fuel System
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Turning off the fuel allows starter to crank long enough
for an accurate diagnosis
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If it is easy….…use a remote starter
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Record cranking Voltsand cranking Amps
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• Starter amp draw will be high until the starter motor reaches maximum RPM
• Cranking longer than 10 or 15 seconds will overheat the starter
• Starter motors that crank slowly lead to starter and battery problems
![Page 14: Diagnose the Starting System](https://reader035.vdocuments.site/reader035/viewer/2022081502/56815be6550346895dc9daad/html5/thumbnails/14.jpg)
Listen for slow cranking
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• Cranking voltage MUST stay above 10 volts
• Maximum Cranking Amps 4 cylinder = 150 Amp6 cylinder = 200 Amp8 cylinder = 250 Amp
• These are ONLY approximate specificationsand not valid on diesel engines.
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Slow turning starters cause trouble
• Engines will be harder to start requiring longer cranking times
• Starters will tend to overheat
• Batteries will wear out sooner
• By carefully listening to many different engines, you will learn to identify slow cranking R.P.M.’s
![Page 18: Diagnose the Starting System](https://reader035.vdocuments.site/reader035/viewer/2022081502/56815be6550346895dc9daad/html5/thumbnails/18.jpg)
Volt Drop Starter Cables
• Resistance in the high amp starter (battery) cables will cause slow cranking
• Replacing a starter motor without checking volt drop may cause the new starter to fail
• High amp starter cables should have less than ½ volt drop.
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Volt drop negative cable(s) starter motor housing
negative battery terminal
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Crank starter to read volt drop
![Page 21: Diagnose the Starting System](https://reader035.vdocuments.site/reader035/viewer/2022081502/56815be6550346895dc9daad/html5/thumbnails/21.jpg)
Volt drop positive cable(s)
![Page 22: Diagnose the Starting System](https://reader035.vdocuments.site/reader035/viewer/2022081502/56815be6550346895dc9daad/html5/thumbnails/22.jpg)
Hook to high amp cable
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Diagnose Intermittent or No Crank
• Intermittent, or no starter motor operation may be caused by a defect in the starter control circuit
• Begin by understanding the system
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This system has 2 starter control circuits.
![Page 26: Diagnose the Starting System](https://reader035.vdocuments.site/reader035/viewer/2022081502/56815be6550346895dc9daad/html5/thumbnails/26.jpg)
Set-up for #1 control circuit.
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Set-up for positive side of #2 control circuit.
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Set-up for ground side of #2 control circuit.
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Defects in control circuit #1, or control circuit #2, will cause intermittentor No Start