Cranking System Voltage Drop Measurements & Testing

Testing the cranking system and starter motor are common procedures for automotive technicians. This video discusses how to perform voltage drop testing throughout the cranking system. Voltage drop testing helps technicians better understand the flow of current throughout the system. This understanding can be crucial to identifying where excessive resistance might be, in order to restore the system to its best performance.
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Components in the video:
- BluePoint Multi-Meter
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[@mymusic3354]

This was the most in-depth detailed video I've seen on voltage drop testing. Great job.

[@GLC2013]

Good looking guy and very knowledgeable. He really knows what he is talking about.

[@a.c.e.7568]

Finally, a well done video on voltage drops. I take it your meter has a MIN as well as MAX hold? You can use the MIN for the voltage across the battery while cranking. An indication of the internal resistance of the battery as it increases with age, that or an abnormally high current draw from the starter. You can also put a probe on the post of the battery as that would take the total drop into account if the clamp has a bit of resistance between it and the battery post. Damn good video from someone that knows something about basic electronics.

[@AdamsAnalysis]

Thanks for watching!

[@lawrencethompson127]

Well done and easy to understand. A very good troubleshooting guide for start problems.

[@AdamsAnalysis]

Thank you!

[@juanlazar8945]

Very useful and good explanation, easy to record, thanks for share

[@AdamsAnalysis]

Thanks for watching!

[@nickayivor8432]

Thanks 👍 From Nick Ayivor from London England UK 🇬🇧

[@AdamsAnalysis]

You're welcome!

[@stanjong2727]

Great video! Great refresher to help me diagnose starting problems .

[@erno9248]

Thanks for the lessons...

[@NCracing3]

My truck will spin the starter a few times as the the voltage drops to 0 and the crank won’t spin. But I can spin crank by hand

[@76kamikazi]

I taught for a minute it was the speaker of the house Mike Johnson working on his car.

[@CollosalTrollge]

@Adamsanalysis how did you do second test by just cranking and not actually starting the car, i dont get it.

[@Lambros_Stefaneas]

nice an interesting video. I learned something new.

[@AdamsAnalysis]

Glad you liked it!

[@timbogtimbog7410]

My voltage drops quite low while starting the car what can be an easy fix? Maybe voltage regulator?

[@marswrld2489]

You did good but sorta failed to mention what the voltages should be on some parts

[@AdamsAnalysis]

Sorry about that. Most connections on the cranking circuit we want to see a voltage drop less than 0.5 volts. One exception is the "S" terminal circuit which can withstand a higher drop and is often specified to have less than 1.0 volts.

[@garylewis3641]

Good video but you look to be over the .5 threshold on the ground side. You might have a corrosion problem on the ground side! Is that how you see it?

[@Emie_CFC]

my car cranking test 9v time start engine. normal or bad?

[@promechanics2395]

Voltage drop between M and B terminal was a nice tip as it is hidden circuit and often it disturbs most of the people.

[@AdamsAnalysis]

Thanks for the comment!

[@deanverno2196]

Hey Adam, I have an 07 chevy cobalt having a voltage drop issue it seems like, I am just getting a clicking noise when trying to start the car. Ive done everything including replacing the starter and cleaning up the connections. It seems like the voltage drops to 5 when cranking to the starter. Im going to replace the wire to the starter tomorrow and hopefully that works. Any suggestions are appreciated

[@AdamsAnalysis]

Hey Dean, Thanks for the comment. Without making assumptions, was a new battery (or battery test) part of the "everything"? I would always start with a known good battery, or assistance of a jump pack and work down through the voltage drops. A starter that only clicks is often due to a lack of voltage (positive or ground) or a failing solenoid. You have changed one of those variables with the starter replacement, so I would get a volt meter and check for drops on the B+ and ground sides.

[@deanverno2196]

@@AdamsAnalysis Thanks for the quick response, i did test the battery and even did a battery swap and all was good in that end. When i try to start the car, the voltage drops down to 5 on the starter. My best bet I would assume would be to work my way back to the battery from there which is what Im going to do tomorrow. Any other suggestions are appreciated

[@SaddamHussaintech4u]

hundred of videos on youtube about voltage drop but no one knows how to fix it

[@AdamsAnalysis]

Are you looking for help in fixing a voltage drop?

[@SaddamHussaintech4u]

@@AdamsAnalysis yes

[@TheMrTslab]

@@SaddamHussaintech4u Repair or replace the part that appears to cause the drop. Begin with the connections to the battery. Move on to the cables. etc

[@gazasquith758]

Don't agree on 0.5v per component, I was taught 0.25v per component.