Ok so I have spent the last few days on and off searching this site and I have not been able to accurately diagnose my problem. It may be more than one, I am not real sure.

96 Bonneville SSEi, 140K miles, supercharged obviously but the belt has been off for a while, I have a radar detector hard wired to the wiring by the rear view mirror. Other than that the car is pretty much stock.

I purchased this car in January and it ran great. The belts looked really bad so I replaced them. At that time the mechanic told me that I needed to replace two pulleys but I didn't have the money. So I just had him put the belt on. A week later the belt for the supercharger broke when one of the pulleys locked up. I beleive this belt is strictly for the supercharger so I continued to drive the car for the next few months. It ran fine, just did not have as much power, although one day in the drivethrough it got a check engine light and sputtered for about 30 seconds and blew some smoke. Then it went back to normal and never did that again.

Now that you know the history, here is my current problem(*).

My boost gauge has never worked since day 1 when I bought the car. I think it may be a vacuum line.

We had some really bad rains about a month and a half ago. At first my power windows would go down but not back up. I though maybe the connections were just wet.

Then I noticed my gas gauge wasn't working. It showed a full tank but I thought the little lady filled it up and she thought I filled it up and we ran out of gas. Aparently the gauge shows full all the time. Not really a huge deal because I can go by the mileage.

Then I went camping and my battery died while we were listeing to the radio. Not a big deal because I had a jump box and jumper cables. But over the next week my electrical issues started getting worse. My battery would be dead in the morning when I would get to the car. Then it started acting really weird while I was driving. When I would floor the gas all on the gauges would rise, tach and speedo included. They would rise slow and steady, not just immediately peg. Sometimes the gauges would completely turn off and back on. I would get numerous lights while this was happening. Volt light, check engine, etc... The car ended up dying on the highway so I pulled over and put the jump box on it and it started right up. Take the box off and it would died within a minute. So I left the box connected and drove to Walmart where I got a new battery and everything was great for the rest of the day. They told me I needed a new alternator since I was only putting out 12 volts instead of 14. The next morning I go to start the car and it is totally dead. I jumped it and it drove great for about 20 minutes before it totally died. Before it died it had no acceleration hardly. Taking off from the stop sign took about 20 seconds just to get through the intersection. I put the jump box on again and drove the car back home and parked it. Over the next few days I got in and out of the car to get stuff and I noticed sometimes the dome light was full bright and sometimes it wasn't on at all so i figured something was loose. I looked around a little and noticed the positive battery cable was really loose. So I went to tighten it down but it was already tight so i took it off and put a washer in it because the bolt was too long for the battery. Then the car started right up with no problems at all. The gauges were still acting intermittent and wacky though when I would step on the gas.

So I went on vaction for 2 weeks and when I came back the car would not start. Not a huge suprise at all so I put the jump box on it and it fired right up. Take the box off and it immediatly stalls.

So that is where I am at right now with the car.
I tried to really take some time on this thread to make sure you guys have all the info but I may have missed something so ask away and hopefully we can get this fixed.

First thing I would do is check the negative terminal where it grounds to the frame.

Already did that. I have upgraded the grounds as well since I was planning on putting a stereo sytem in it at one time.

When you say you upgraded the grounds, are you talking about the ones that run under the driver and passenger doors? Almost every post I read about gage/interior electrical issues asks that question.

HTH -
Matt

Always, it refers to where the negative wire from the battery and other wires as well bolt to the frame. Often a sore spot with Bonnevilles.

Midco it sounds like the internal voltage regulator is on the way out. Car can do weird things when they go and you certainly got some going on.

I just finished replacing the altenator, jump started the Bonne and she stayed running when I removed the cables. When I revved the engine the gauges were all good except the boost gauge since the belt is not on for teh supercharger. Also the fuel gauge is still reading full when I know it is not. I was pretty sure this was unrelated to the power issues so now i have to figure out what is wrong with the fuel gauge.

You can check if the sender is bad by unplugging the connector at the fuel tank and turning the key to on (not run, only on). Then put a resistor of 45ish ohms between the pins for B and D on the vehicle side connector and turn the key to on. This should be somewhere about half. Toss in a resistor for 90 ohms and read the gauge. If all these tests work as mentioned, then it is most likely the sending unit in the tank.

Great, I just love going inside tanks. I am pretty sure it is the sender simply because it is pegged when running but dropped when the car is off. I will definitely test it though. I probably need to open the tank anyways and clean all the broken baffles out. I was told that all the plastic baffles break up and float around on these cars.

From experience I doubt the broken baffles for your year. That was common to the 92 and 93 years.

I am a fan of testing first and then replacing if needed. But then I joke that my engine, transmission and fuel tank are held in with velcro, because they've been out so much.