Okay, here's a new one for me. I have a 93 Camaro Z28 which is fairly modified (all but the shortblock). Several months back, I relocated my battery to the trunk. The only way to run it properly was to run the cable to the starter, then a wire from the starter to the alternator. Well, unfortunately, my bad, I didn't do it right the first time, and the battery cable got some slack in it, grounded out on the exhaust and screwed my Optima battery up. I drove it like this for a few months, because at the time, I didn't know what the problem was. Anyways, after getting a new Optima and splicing out the part of the cable that was fried on the exhaust, it seemed to fix all my problems...until now.

When I first start the car up, it has a full charge from the alternator. After it warms up, the voltmeter will drop one bar, and if I drive it long enough, it drops two bars. I figured it was an alternator on its last legs, so I just ignored it and figured it'd go out when it goes out...and then it happened tonight. I don't really know how to explain it all, but essentially, there was a faint odor of something burning/cooking from under the hood. The voltmeter behaved as if the alternator crapped out- gauge was "in the yellow", lights dimmed, needle slowly dropping. In addition to this, the tachometer and speedometer were going completely nuts. The tach seemed to read roughly double the engine's real RPM (it would read 4000, when I was probably driving @ 2000), and the speedometer was WAAAAAAAY off. When I'm at idle, it sat @ 40mph. When I'm going about 35-40 mph, the speedo reads somewhere around 130-150mph! It's not affecting how fact the odometer turns over, but clearly something's jacked up.

Now, it's obviously a problem in the ignition and/or charging system, so let me start by listing the mods I've done in that area. For ignition, I have a Delteq DIS, and on my charging system, I have a 140-amp alternator (from a 94-97 LT1), a voltage booster that runs from the alternator to the fuel pump, and as I mentioned before, I have an Optima battery and have relocated the battery to the trunk. My gut says it's one of 3 things. I'm thinking either the alternator is done for...OR the alternator-to-starter wire got cooked somewhere on the headers...OR the voltage booster wire got cooked and is grounding out. Can anyone here give me any ideas they have? Could it be something I haven't list yet?

 

It was the alternator. It's bunk. Just FYI...

 

When replacing the alternator, I examined the wires around the alternator. Apparently, about 18" of wire for the fuel pump voltage booster was COOKED. I spliced it and added an extra 8" of wire to have more "play room" to relocate it in a better spot, then I sleeved the whole thing in a thermo sleeve, to prevent it from getting cooked again. We'l see if that solves everything...