am I doing something wrong?

[truckofwinandawesome]

Update: we checked the Alternator Output, and its only putting out 13.4 Volts when the Headlights off, and only 12.95 Volts with the headlights on; it seems the Alternator is BARELY Keeping up on its Charging Duties. and and every once in a while if you rev the engine, it will backfire through the Throttle Body; it was found that Spark Plug Wire #5 is partially burned, and is suspected to be the cause of the Backfire.

[Jsdirt]

If your ambitious, you could disassemble the alternator and try running some emory cloth over the copper that the brushes ride on. If the thing sat for a long time, they can tarnish up pretty good. Would be a good learning experience for the class too.

 

That may, or may not be the problem though - these days the electronics (and bearings) inside leave alot to be desired.

[Doug_Scott]

Also make sure the battery is in good condition and fully charged. As stupid as that sounds, to get the proper output result, the battery needs to be fully charged, and in good condition. Are you testing output at battery or at the alternator? You should also verify that the alt belt and pulley are clean and dry.

What is the voltage when you hold the engine at 2000rpm, both with and without a load on it?

[Jsdirt]

^^^ +1 - simple stuff first.

[truckofwinandawesome]

We had the starter rebuilt, and it cranks a whole lot better; but we went ahead and put it on our shop's midtronics Battery/Starter/Alternator tester, and the new battery, and rebuilt starter passed with flying colors; guess what failed its test!

 

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[truckofwinandawesome]

Also make sure the battery is in good condition and fully charged. As stupid as that sounds, to get the proper output result, the battery needs to be fully charged, and in good condition. Are you testing output at battery or at the alternator? You should also verify that the alt belt and pulley are clean and dry.

What is the voltage when you hold the engine at 2000rpm, both with and without a load on it?

the voltage without a load was 13.78, and with a load, it was 13.18; it pretty much failed the test with Low Voltage. but its Not My Problem anymore, because the Owner Picked it up this afternoon!

 

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