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new battery and alt and still slow crank

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Old Dec 13, 2010 | 03:48 PM
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From: east hampton new york
Year: 1996
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Default new battery and alt and still slow crank

I just replaced my battery and the alternator because I was getting slow cranks and if I turn my lights or heat on the gauge goes way down . but even after that it is still doing the same thing should I look into replacing the starter before I get stranded somewere
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Old Dec 13, 2010 | 03:58 PM
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Originally Posted by g19n87r
I just replaced my battery and the alternator because I was getting slow cranks and if I turn my lights or heat on the gauge goes way down . but even after that it is still doing the same thing should I look into replacing the starter before I get stranded somewere
Check battery to engine and battery to frame ground connections.

Unbolt them, clean them and re-install.
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Old Dec 13, 2010 | 03:59 PM
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From: east hampton new york
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well it just got dark so ill try it in the morning but is that an explanation for why they would be drawing so much when I turn any accesories on
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Old Dec 13, 2010 | 04:00 PM
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Originally Posted by g19n87r
well it just got dark so ill try it in the morning but is that an explanation for why they would be drawing so much when I turn any accesories on
yes
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Old Dec 13, 2010 | 06:00 PM
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Grounds can be the root cause of many electrical gremlins. Refreshing grounds is NEVER a bad idea!

You can't just check or look at these grounds. You must remove, scrape, clean until shiny the cable/wire ends and whatever they bolt to. The one on the back corner of the head, and where it attaches to the firewall. Scrape the paint from the firewall. Best to replace that woven cable with a #4 or #2 gauge cable. You can attach the one end to the intake manifold if you would like.

Next go over to the engine dipstick tube stud. Remove the nut and clean the wire ends and scrape the block until shiny at the stud. Reattach tightly.

If you are so inclined, add at least a #6 cable from the negative terminal of your battery to one of the bolts on your radiator support. Scrape the paint off first.
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Old Dec 13, 2010 | 06:10 PM
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Originally Posted by tjwalker
Grounds can be the root cause of many electrical gremlins. Refreshing grounds is NEVER a bad idea!

You can't just check or look at these grounds. You must remove, scrape, clean until shiny the cable/wire ends and whatever they bolt to. The one on the back corner of the head, and where it attaches to the firewall. Scrape the paint from the firewall. Best to replace that woven cable with a #4 or #2 gauge cable. You can attach the one end to the intake manifold if you would like.

Next go over to the engine dipstick tube stud. Remove the nut and clean the wire ends and scrape the block until shiny at the stud. Reattach tightly.

If you are so inclined, add at least a #6 cable from the negative terminal of your battery to one of the bolts on your radiator support. Scrape the paint off first.
Also if you're going to take the time to upgrade the grounds, some Penetrox is a good addition. It keeps things clean and is available at Home Depot / Lowes.
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Old Dec 13, 2010 | 09:27 PM
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Originally Posted by g19n87r
well it just got dark so ill try it in the morning but is that an explanation for why they would be drawing so much when I turn any accesories on
Not necessarily.

Your alternator is good for about 40% of max rated output at idle - at best. If you've got a lot of accessories on at idle, voltage will drop as current demands are high. Current and voltage are mathematically related in a closed electrical system (cf: Ohm's Law, Watt's Law.)

I usually use Ox-Gard to protect ground connexions from corrosion - it's an electrical corrosion inhibitor. You should be able to find it or something similar at your local hardware/DIY store in the electrical section (don't half-*** that - use a proper electrical corrosion inhibitor. I've made plenty of money over the years by cleaning things like WD-40 out of electrical connexions!)

Over the last thirty years, I think I've traced fully 70% of automotive electrical problems to shonky grounds, and I've gotten to where it's what I do first after gathering symptoms and before any actual troubleshooting (gather symptoms as a baseline so I know what works and what doesn't, and refreshing grounds can often solve electrical problems that are otherwise resistant to troubleshooting.)

If that dipstick tube stud comes loose, get a 3/8"-16x1/2" screw (if you can find one!) or 3/8"-16x3/4" (if you can't, get a few flat washers with this) and replace it. Brass is best, CRES is second best. Do not get a "black oxide" coated screw!

Chassis ground contact points should be cleaned down to bare metal and a corrosion inhibitor applied. Replace screws PRN, clean rings.

If you have a RENIX (1990 or earlier,) adding a ground from the battery to the fenderwell won't go amiss - treat as above.

Oh - and make sure your starter is mounted tight and clean. It grounds through the mounting to the engine - if that's loose or dirty, the ground will suffer and cause trouble (thumb rule is that the ground return is the same size as the supply line or one size larger. If the ground is smaller - actually or effectively - it will act as the bottleneck for current flow. If you have a 10AWG feeder lead and a 18AWG ground lead, you'll only flow what an 18AWG wire can handle.)
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