I Think It's ALTERNATOR?

[pats10350]

I started my 87 350 S-10 today. It sat up all winter. It had a trans leak at the speedo gear and pan gasket. After fixing all of that I was going to run it around the block. I went to start it. It turned over but soon ran out of juice. I jumped it with my other truck, and it started fine and ran good. I let it warm up and added the correct amount of trans fluid. I got about a block up the street went to hit the gas and it hesitated, It soudned like it was missing, then it died. At first I thought it was out of gas. It tried to turn over. I thoght It was a low battery. But it was wierd my door poppers worked great like the battery was fully charged. I walked home and got my wife to jump me. I put it in gear and it died. Im thinking its probably the alternator. I have owned the truck for about a year and a half. I always thought the alt was a little weak, when you hit the gas all of the lights would get brighter. The past few times I drove the truck it did the same thing. It would miss, but would'nt die. The trans was low, so I thought it was a power transfer problem. I haven'nt checked any fuses or wiring. Does anyone have any ideas?

[chris1972]

need to check the charging rate og the alternator..should be 14.1....that what i would do first...sounds like a alternator

[spacecadet]

Also check your ground wires. There should be a good ground wire from the battery to the block, the battery to the body and a ground from the block to the body.

Space

[pats10350]

First thing I did was check the battery grounding. The battery was moved to the right rear. I had recently put in a new battery and negative cable to the frame. Ther's not a ground from the battery to the block, just the ground from the battery to the frame. I cleaned up any corrosion on ground, then checked battery voltage, I had 11.6 volts. I checked all wiring, and fuses. I tried to turn it over, barley anything, but all accesorys worked. Then I jumped it. I did a voltage check across the terminals on the alternator. I was getting a little under 10 volts at idle, and it would drop with throttle. The belt has some play in it but I think it's the alternator. I should have been running more than 12 volts. Should I check the battery too when its running?.

[manyfire]

sure its not the fuel pump? Take the batt and alt out and take to autozone, they will put a full charge on the battery and test the alt, then you will know if it is one of them and begin troubleshooting other systems.

[Scotty_S-15]

A couple thoughts:
* Did you mention a full size ground (negative) between frame and engine block? Need one. Very important.
* Alternator should be 14+ volts at a high idle like Chris 1972 said. Check the voltages at the battery AND the alternator to eliminate a wiring problem. Battery should read 12.8 with engine shut off and a small load like interior lights.
* The stalling may or may not be related to THAT electrical problem. I'd guess it's a different problem. Still could be wiring or fuel.
* It ran fine last year with no changes since??
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[Ryoung68]

A ground from the engine to the frame and body are needed unless you are running solid motor mounts. Electical circuits need a good ground to operate efficiently.

[Scotty_S-15]

I've seen the results of a lack of (good) negative cable between battery and block many times...... a couple of the more amusing ones....
* guy calls me, said the engine in his Shoebox Nova is overheating, but his brand new motor hasn't even started yet.:crazy: Seems the best path the starter could find to ground was his mechanical temp gauge..... the mechanical tube was "burn your hand" hot.:icon_lol:
* Another one was, "the engine has been cranking over slowly for a long time". He told me this after his clutch cable actually burned in half! Think it was a Pinto...... the mechanical clutch cable was apparently carrying the starter current.
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