Hey guys i recently over heated my car and cracked the heads on my 2001 Chev. Monte Carlo, so i went ahead and got ahold of another 3.8SC motor. My prob. is that ever since the motor was swapped out my fuel guage either marks FULL or EMPTY, once in a while the guage drops down to 3/4 but the car doesnt have that much fule. Has anyone had this prob. before, im stumped on what it could be so that why i come to u all here looking for some else.

Forgot to mention the motor on there was a 3.8 N/A with a topswap on it.

 

It could be your stepper motor in you gauge..

LINK:https://montecarloforum.com/forum/si...lem-fix-12319/

 

humm... so what would that be? and it just seems weired that it happened right after doing the motor swap.... anyone else with an input?

 

It could also be the sending unit. GM had some problems with them on several vehicles. You could also have a ground issue at the tank.

 

i was thinking of the sending unit and also the ground BUT the tank was never messed with, then i got to thinking it might just well be the sending unit

 

Since the problem began right after the engine swap I'd take a look at the wiring going to the underhood fuse panels. A loose/dirty connection or pinched/frayed wire/insulation could cause erratic gauge operation.

 

for the record i had the same issue. It was fuel sending unit. Got a new one on ebay for 20 bucks free shipping!!

 

I say fuel sending unit. Common issue. I'd replace the sending unit and fuel pump at the same time, problem should be solved.

 

I had a similar problem on my 2000 SS. It ended up being part of my float on my sending unit. It's a little piece with 4 finger like things(Fuel level sensor) that work up and down with the float. The very ends of them were worn off causing it to jump all over the place. My mechanic friend at my local Chevy dealer got the part for me. He said it's a common problem with these cars and Chevy trucks. I pulled my sending unit and replaced it. It worked great after doing this. I was told the only thing I could do was replace the whole unit. It was time consuming but only cost me $20.

 

It COULD be the stepper motor but sounds more like the sending unit going out.