Can you run a 96 Yukon without a battery & not damage it.

[Chris142]

The alt is designed so that if it does not have a battery hooked up it won't charge.

GM did this to protect the electronics from backyard mechanics that disconnect the battery with the engine running to test the alt.

 

[Eddie]

Sounds like an expensive way to test GMs "it won't charge if the batterys disconnected" I go with Dan4510 on this one as a electronics redo is very expensive and time consuming.

 

[eljefino]

Jeez, just hook up a voltmeter anywhere in the system. 13.5v == alt working; 12.0v == alt not working. There are tolerably accurate digital volt/ohm meters at Big Lots for $5.

 

[Chris142]

quote:

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Originally posted by eljefino:
Jeez, just hook up a voltmeter anywhere in the system. 13.5v == alt working; 12.0v == alt not working. There are tolerably accurate digital volt/ohm meters at Big Lots for $5.

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And if yer really cheap........ Start the truck, wait a minute for it to settle to an idle, turn on the lights and A/C. The Alt will make a whistling sound if it's working.

Not as precise as a volt meter but works for me

 

[Jim Spahr]

In a modern GM vehicle ('96 GMC Yukon), can you run the engine at say 1500 RPM with the battery disconnected and not harm the alternator, regulator, or PCM-computer? I know in the old days, this was sometimes done as a test to see if the generator and regulator was working! Now I believe it is not a good idea. Why? What is likely to get damaged?

 

[Dan4510]

i would not do this. every electronic on it can be fryed. The battery buffers the larger voltage swings.

Dan

 

[Jim Spahr]

Ellie and Chris, this question didn't come up to test a car's charging system. I actually asked it for a friend who has a 96 Yukon. The truck's positive side terminal became so corroded, the truck wouldn't start. BTW this is a common problem with all GM vehicles with side terminals. We discussed the problem and the question was asked: 'What would happen if you had a severely corroded positive terminal and jumpstarted the vehicle with another battery?' Once you removed the donor battery, would the engine still run and, if so, would it damage anything? I did toss in a comment regarding the old school method of testing a car's charging system.

 

[Gary Allan]

quote:

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and the question was asked: 'What would happen if you had a severely corroded positive terminal and jumpstarted the vehicle with another battery?'

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But that's not the question that you asked. Stated this way ...then one can simply say that the batt/alt output to maintain the vehicle running is NOTHING compared to starter demand. You don't need that good of a connection. 12 or 14 gauge wire could probably run the car ..but you need 4 or 6 to start it.

Stated this way ..unless the battery itself is null and void ..sure! I've had batteries so shot that putting on the brake would stall the engine. I also don't think that you can excite the windings without a battery.

 

[VaderSS]

The thing to keep in mind is that the alternator is putting out a rectified AC. That means that the average will be around +13.5V, but that the peaks end up much higher. Pulling the cable puts those surges into the system, rather than the battery. Will it run? Sure, but every second is subjecting the system to hundreds of voltage surges. This is also very hard on the regulator and will shorten it's life.

 

[CardGuy]

I had a 98 tahoe and it developed a bad ground cable to the battery. (actually the side post of the battery stripped and would not maintain contact with the wire) The vehicle would not run at all once it lost contact. As long as the contact was not there with the ground wire you could not even jump the vehicle. Sometimes a bump would loosen up the wire enough to cause it to loose connection and stall. Soon enough I found the cause and got a new battery. problem solved. So to answer your question, in my experience with a 98 (not 96) the truck will not run with the battery disconnected.