Automotive Repair: Testing Starter Circuit Voltage Drop (Ground side)

Automotive Repair: Testing Starter Circuit Voltage Drop (Ground side)


voltage drop is simply the measure of voltage potential between the points where your meter leads are connected in this case I’m connecting at the battery negative terminal and the other is going to the engine ground so when I start the car I’m going to put in a full current load through the starter motor through that ground circuit if there’s any weaknesses between the starter circuit ground the engine ground itself and the battery negative ground then I’ll need to isolate the circuit further to determine exactly where that cause is so let’s crank the engine I’m gonna set the meter on record since it’s just me and let’s see what the what the voltage drop is go and pull up the maximum reading point 180 volts in this case under starter current draw that’s the most current at any one time that this is electrical system is going to have to deal with this ground side connections going to have to deal with I’d say that’s more than fine half a volt 2 volt max for the starter normal circuits with lighting car running blower motor that type of thing no more than half of old electrical circuits on the ground side no more than 1 or 2 tenths if I’m going to go across any one particular point like if I wanted to check between the negative cable and the post itself again they’re no more than I see one or two tenths that’s going to be affected by the accuracy a meter got to give it a little bit of leeway but in this case our ground circuit from the engine back to the battery is fine


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