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I once had a battery come loose while on a long trip. It bounced around and came to rest against a pulley, which promptly ground it way through the rubber side of the battery, which spilled out the acid. We quickly replaced the battery at a roadside auto parts store but it wouldn't start with the new battery. We could push start it as it was a stick shift.
Turns out the battery acid ran down onto the battery cable ground wire that bolted to the engine block and set up a thin film of corrosion between the block and the cable. Once I was removed that corrosion with a bit of sandpaper it was perfect for the rest of its years.
Simple thing to repair for the price of a small square of sandpaper.
This type of high resistant fault is easy to locate via a voltage drop test under starter load. Typically, you'd want to see a maximum of .2 V voltage drop across any major ground connection. This is taught in automotive electrical class 101, basic intro to electrical systems.
Having worked on so many Euro cars, this type of testing ... as well as cleaning of ground cables/circuits ... was essential for routine maintenance and tuning of the vehicles. The wiring and connector materials in certain car brands were legendary for corrosion and associated failures, especially in Brit and Italian cars.
Of course, the grounding failure you describe has no relation to the failure as described by the OP.
BTW that test works on postive post to postive clamps too. 2 weeks back the motor for my dump truck lift seemed to have failled, and the motor whined and ran jerky. The fault was at the pos post and the pos clamp and I got more than 0.2 drop right there.
BTW that test works on postive post to postive clamps too. 2 weeks back the motor for my dump truck lift seemed to have failled, and the motor whined and ran jerky. The fault was at the pos post and the pos clamp and I got more than 0.2 drop right there.
Yes, the guideline max .2V drop across heavy power connections or cabling under load works throughout the vehicle.
As a guideline, the max voltage drop under load is .1V for routine power consumers in a car for connections or cabling.
I prefer to see less than that for computer sensor circuits, which are light loads.
Sun, You do understand besides you n' me 8 other guys know what we are tawkin' about right?
I was kinda' hoping that there were more ...
or that the direction of the thread would allow the folk who are on here to realize that there's more to automotive electrical/electronics problems than just a failed battery ... and
that there may be a point in time with their electrical problems to seek out the services of a professional rather than just swapping out batteries ....
or that the direction of the thread would allow the folk who are on here to realize that there's more to automotive electrical/electronics problems than just a failed battery ... and... going to A-Zone for a free whatever checkup...and...
that there may be a point in time with their electrical problems to seek out the services of a professional rather than just swapping out batteries ....
A lot of posts are mentioning the 'alternator'. It's probably not the alternator but the voltage regulator in the alternator. If you have an electrical multi-tester, [$5] set it to DC 20v, place probes on battery. Reading should be 12.6-13v. Start car, when volts drop, voltage reg will kick on and meter will show volt increase to over 13v. If no changes, volt reg is defective.
Also, battery connections must be tight, and the neg. ground must have a clean, tight connection to ground [which could be frame, body]
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