78 Firedbird Statrer..Excessive Amperage.

that does sound like a lot; an older V-8 starter typically draws

2-400A *under load.*

nate

How did they test it, then?

I'd agree with that, but you really want to test it under load.

It seems awfully high for having no load on it, but it does not sound like a very useful test.

Anyway, you already know that you have a problem either with your starter, your battery, the connection between the two, or the engine.

Measure the voltage across the battery and see how much it drops when you crank. Then do the same thing at the starter. This will tell you what you want to know, because you will be testing it with an actual load on it.

Have you first verified that your engine isn't locked up?

--scott

The last 70's GM starter that did that to me was in 90 and I went to the GM dealer and they sold me a set of 4 brushes for $1.00 each which I installed and the starter was good to go again. I have done the same with a mess of Jeep starters also.

You also can get kits for them that come with new nose bushings.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 'New' frame in the works for '08. Some Canadian Bush Trip and Build Photos:

The engine is'nt locked up. I can turn it by hand.

The test at the first place basically just hooked up the starter to 12 volts and let is spin.

The secound test showed the amperage draw. It was at 100 amps.

I was told that the average for this starter was 50 without load and then should drop.

Thanks.

I'm confused.

Are you sayiong that 100 amp draw is excessive and would cause the symptoms I discribed? Thanks.

Okay, this is good.

This is a totally useless test that tells you very little.

This is a slightly useful test that tells you that you have a good chance of having a shorted turn somewhere on one of the windings. It is not at all definitive, though.

That sounds reasonable, but you won't know for sure unless you put it back in the car and test it under load.

Still, you have the thing out, you might as well just get a replacement anyway since it's most likely to be the problem.

--scott

Is it the correct battery in there? What's the cranking amps of the battery?

Yes, worn out brushes can cause this high load. If it is full of mud, it can also load up. A can of WD40 does wonders for cleaning them out and new brushes are easy to solder in.

For it's age though, if it original, then a store bought rebuild may be in order.

Mike

my starter just clicked when i turned the key. I did this modification and its good now. Basically its adding a ford solenoid to the gm starter.

my starter just clicked at times, especially when hot. i had it rebuilt and it was worse. i did this modification now its ok. adding a ford solenoid to a gm starter.

UPDATE:

I found the problem.

The previous owner had removed the grounding strap from the engine to firewall.

I also mounted a grounding strap from the trannie to the frame. She cranked right up.

Thanks all who commented..

Good stuff. But since you already identified a high current draw of the existing starter, you might as well consider pulling it one last time, and kitting it. All you really need is an old hacksaw blade, the kit itself (basically two bushings and a brush set,) some basic hand tools, and a can or two of electric parts cleaner (CRC sells one that is found at most FLAPS. It's basically like Brakleen but doesn't eat the varnish on the armature.) You might be pleasantly surprised with the results, and then you'll know it's good for another decade.

nate

That would do it! This is an easy problem to figure out with the meter... when you crank, the voltage across the starter drops WAY down, but the voltage across the battery hardly drops at all, which indicates some sort of resistance between the battery and the starter. Metering between the starter body and the negative terminal of the battery shows will show that it's the ground.

I believe the first comment I made was that the bench test was not useful and you needed to measure battery and starter voltages in the car. The meter is your friend and will tell you everything you need to know.

--scott

So many guys forget that solenoid contacts burn out or oxidize. There IS a starter solenoid in this car, right? Put a voltmeter across the solenoid's big terminals, set it so that you see 12 or 13 volts on the meter, then try to crank; if the voltage doesn't drop to zero or something really close to it (much less than 1 volt), the solenoid is shot. Do this same sort of test on all the cables too because they can corrode or otherwise fail inside their terminals. Any resistance will reduce current flow enormously. Most guys will start spending money on batteries or starters. Parts shops love this sort of thing. When I was in the air brake compressor, control valves and actuator rebuilding business, up to 80% of the cores that came in had nothing wrong with them. The mechanics didn't understand the systems (they're not all that simple) and therefore could not intelligently troubleshoot them. They'd just start replacing parts and hope that they'd somehow get lucky.

Dan

If its original, no way in HELL would I replace it with a store-bought POS rebuild. I'd have it rebuilt at a local starter/alternator shop, or send it away for a rebuild (even if I had to buy a POS store-bought rebuild to keep it running in the meantime.)

And above all NEVER EVER turn in an original starter as a "core" for a store-bought crappy rebuild! They're few enough un-molested ones out there already.

Nothing is going to be better than the factory unit. If it's original it is worth the effort to save it. After my last experience with a reman distributor I'm done with reman units. I did keep the original so I can redo it if I ever need to, its vacume advance/retard unit is on the reman I ended up with because the carquest one had the retard side soldered shut with no diaphragm. The second one they gave me was much less molested than the first, but I still had to sand a part they left as as-cast that was machined on the original. I might make an exception if was reman'd by the OEM but that's it. Other than that, I either fix it myself or just pay for a new OEM part. It's not worth the hassel otherwise.

Now that you mention that, I remember several Camero/firebirds with this same problem. With no engine ground, these things would ground through the shifter cable and melt the liner, causing hard or no shifting. Speedo cables could also be affected. Ben

I'll agree on the distributors, they are putting out units that destroy cams these days because of poorly made china gears that are too hard.

But when it comes to 1978 starters, all the dead ones I have seen were really dead. Most had serious bushing wear that was damaging to their case.

I did recommend he pursue the thought of putting a set of brushes in it or getting a store bought rebuild if he cannot do it himself.

What part of having a store rebuild his starter is an issue?

Mike

I got an original junkyard starter at the U-pull and replaced the front case on one that had cracked at a screw boss.

store rebuild sounded like buying a reman from pep-boys or similar, not having his starter rebuilt.