88 Alternator issue

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Dec 27, 2004 | 08:38 AM

Lee A. McKinley

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Cruising

Joined: Dec 2004

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88 Alternator issue

Guys heres an easy one hopfully. Can any of you tell me what and where to measure the alternator charging current for an 88 vette? There are two red wires on the alternator and Im sure one of them will tell me the current that the alternator is providing to the batt. But not sure which one and what is the normal current I should read at idle, nothing else on. None of the manuals mention anything like this. Im asking becuase the alternater is screaming at idle and getting hot fast. One of three things happened I think. A bearing went, the stator internally now has a short or I have a short in the harness somewhere. Your thoughts.

Dec 27, 2004 | 08:58 AM

Chris_G

Melting Slicks

Joined: Nov 1999

Posts: 2,281

Likes: 129

From: NOVA

St. Jude Donor '05-'06-'07

Quote:

Originally Posted by Lee A. McKinley

There should be one large red wire mounted on a post that goes to your battery, that is where you check your current as stated above. Unless you have the proper eqipment probably the best you will be able to do is check voltage? I'm not sure what kind of test equipment you have?

I hope this helps.

Chris

Dec 27, 2004 | 09:08 AM

the blur

Melting Slicks

Joined: Apr 2004

Posts: 2,774

Likes: 138

From: cyberspace NY

basically.... alternators of that era are junk. I've been through 5 in a short period of time. Even the NEW pep boys with the lifetime warrenty are junk.

I've been having luck with 2 grounding straps. one behind the alternator, and 1 in front, directly grounded to the frame.

I'm not sure if that is a solution, but I havn't had a failure since then. Only time will tell......

Dec 27, 2004 | 10:52 AM

Flame Red

Le Mans Master

Joined: May 1999

Posts: 6,517

Likes: 1,304

From: Windermere FL

When I got sick of spending my lifetime replacing the Pep Boys alternators every few months under their lifetime warrenty, I got a alternator from http://www.powermastermotorsports.com/ and have never had any troubles since.

Dec 27, 2004 | 10:58 AM

C4Ownr24

Racer

Joined: Oct 2004

Posts: 286

Likes: 1

From: Washington DC

The only real way to check output capacity would be with a VAT-40 type machine (load testing it.) A fluke meter or basic multi-meter can only handle 5 or 10 amps unfused. Some auto parts shops will test it for you....

Dec 27, 2004 | 01:22 PM

jfb

Team Owner

Joined: Mar 2001

Posts: 54,124

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From: Cincinnati, Oh USA

A clamp on dc ammeter around the large red wire off the back of the alternator will tell you the current it is delivering to the electrical system. The lowest cost dc clamp ammeter I know of is at Sears for $49.95.

Dec 27, 2004 | 05:16 PM

C4Ownr24

Racer

Joined: Oct 2004

Posts: 286

Likes: 1

From: Washington DC

You can buy the ammeter, but there's only so much load you can put on your alternator (by turning the accesories, etc, a/c on.) The regulator will only let the alternator produce whatever voltage/amperage is needed by the vehicle. So just seeing what your alternator is putting out at idle or higher RPM w/out a heavy load is almost useless. just my 2c.

Dec 27, 2004 | 09:57 PM

korvette4u

Drifting

Joined: Oct 2003

Posts: 1,594

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From: CALGARY ab

Quote:

Originally Posted by Lee A. McKinley

normally output voltage 13.7 -14.5...amperage at idle is about 25-35 amps for a cs 135..

if you continue to have problem change the alternator to CS-144,,same voltage output at idle,,but about 45- 50 amps at idle..total out put at operating rpm is up to 155 amps .. thats enough to weld with

this puppy bolts right in..(may have to reclock to relocate plug in same place).. i just did this to my 87,, no more alt problems...