Starter Circuit Voltage Drop

This video shows testing starter circuit voltage drop on a Toyota Pickup that would not crank.

Category:

Autos & Vehicles

Tags:

• starter
• circuit
• voltage
• drop
• motor
• sport
• auto
• automotive
• technology
• cars
• trucks

[Juusstas]

How he got 12V between +starter and +battery pins at the beggining, if at the end he realised, that voltage drops between clamp and wire's washer? If the starter got 12V at the beggining, so what is wrong? car should start up normally. Am I right?

[ttcautotech]

@Juusstas In the video we are using the direct method of measuring voltage drop. One lead is placed at the beginning of the circuit (B+ at battery) and the other is placed at the other end of the circuit (B+ at starter). Any voltage lost between the B+ and the starter B+ will show directly on the meter. We are not measuring voltage to the starter! Since both our meter leads are on the B+ circuit the meter will show the total voltage lost in the B+ circuit. We had 12v at batt but lost in circuit.

[scootbmx01]

its the ground, same thing happened to mine

[ttcautotech]

@scootbmx01 Hmmm, did you actually watch the video? lol. Voltage drop is measuring the voltage difference between two points. ie. wherever you put your two leads. In this case the meter read 12volts. That meant that the difference in voltage between the clamp and attached eyelet was 12 volts! Since these two points are touching they should have exactly the same voltage. They did not! Notice it was the POSITIVE Clamp that had the voltage drop between the clamp and the eyelet..

[scootbmx01]

@ttcautotech i was just listening to the clicking sound, i had the exact same sound, grinded my negative post and clamp and it worked fine :)

[ttcautotech]

@scootbmx01 Ah yes. Voltage drop on the ground, while not the problem in our case, would cause the exact same symptoms. A bad connection on either could cause the starter to just click.

[kneedown4GOD]

great vid,you really simplify the voltage drop test.it sometimes takes time to wrap your head around it but once you do, voltage drop can really be a life saver.

[505197]

Volt drop tests are intresting, mainly due to the fact there is no "standard" . How many volts should I see drop between the alt and the battery? How many tenths is ok and at what point is it too high? I read .2 volts for a 70 amp output and kinda go by that as a standard. Resistance generates heat, how many bad cables have you found just by feeling a terminal? I saw a Japanese guy workin those multi-meter probes like they were chopsticks, man was I envious, he was precise as could be

[donkason]

Simple and easy tutorial on what can be an elusive problem. Thanks a lot fellas!

[TruthBomber]

Thanks for this video, I like how you didn't gloss over anything, but showed exactly where to probe for each different portion of the circuit. Very well explained. I was able to methodically pinpoint my problem area as the interface between ground wire and clamp. Put a new clamp on, cleaned the wire, and solved a very frustrating, intermittent problem. Thank you!

[DusterMtnEX]

I just want to say thanks for this video. I've spent days reading electrical mumbo jumbo trying to learn about this and other concepts of testing DC systems. I've learned more here in 6 minutes than I have learned in the last 6 days.... Now if I could just understand how I can have enough supply voltage to a good coil but not enough flow/current/amps to make a nice fat spark instead of a skinny orange spark....

[freshXtuna]

NiCE thanks :)