So my Buick regal with the 3800 lost power on the highway. Got it towed and diagnosed. The shop said it was the fuel pump fuse and said they inspected the fuses along with relays and wire harnesses that they had access to besides the ones that they couldn’t get access to without removing interior parts. They said they didn’t find the source of why it blew. I am wondering if it just happened out of old age and miles (187k) or if there’s something they could have missed
You could use a test light. Remove the fuse.
Test light Alligator clip to battery positive and touch the side of the fuse terminal that's going to the fuel pump relay/fuel pump. If it lights (even dimly) you have a short in the fuel pump or the wiring going to the fuel pump.
But a worn fuel pump motor will also pull high amps when it tries to get started.
It gets stuck and that will blow the fuse.
If you have an amp clamp for your multimeter, disconnect the fuel pump connector. Put power and ground to the fuel pump with your amp clamp on the positive wire and see if it's pulling more than the fuse is rated for to start
But that's not what I'd do because I'm lazy.
I'd leave the fuse in, leave the relay in, and disconnect the wiring connector at the fuel pump.
Turn the key on. If the fuse doesn't blow I'd condemn the fuel pump
Well being that old and being an American car sometimes fuses just get corroded and will blow because of the added resistance of the corrosion. But if your fuel pump is really old, odds are the thing is starting to wear out. If it blows the fuse again, I would replace the fuel pump and check the wiring harness that feeds the fuel pump. Those often start to erode when they go into the gas tank or on top of the tank
@scottykilmer Good point. Thank you! Additionally, a few days prior I had the cigarette lighter fuse blow. Do they generally go bad around the same time? Again the shop said that they checked all of the wires but did not say anything else when I told them I had one blow a few days prior for the cigarette lighter. They did not mention anything about the fuel pump either.
Additionally, a few days prior I had the cigarette lighter fuse blow. Do they generally go bad around the same time? Again the shop said that they checked all of the wires but did not say anything else when I told them I had one blow a few days prior for the cigarette lighter. They did not mention anything about the fuel pump either.Scotty normally answers questions once and doesn't revisit them. If the cigarette lighter fuse and the fuel pump fuse are on the same circuit then yeah, it could be related. If they are on separate or different circuits, it's more likely to be a coincidence.
@hixster the cigarette lighter/charger port fuse is on the interior and the fuel pump one is on the engine bay fuse block
@chaseando16 That's 2 different fuse blocks so it's probably not related. Scotty's right (of course) about fuses blowing because of corrosion. Corrosion can cause resistance and heat, particularly in the immediate area where the corrosion has occurred. I replaced the cigarette lighter fuse in my 28 y/o truck a couple of years ago and the entire fuse was green from corrosion. I cleaned the connections up a bit before popping a new fuse in. It still works fine today.
@hixster I saw that scotty mentioned it could be the fuel pump getting old. My fuel float/gauge seems to be inaccurate and will move to almost empty then right back up to quarter tank. Think its time for a fuel pump?
@chaseando16 Fuel pumps can get weak over time. You could pressure test the pump to remove any possible guesswork but I do believe Scotty's right. This situation isn't unusual at all.. it's been in there for over 20 years. Older fuel parts often acquire some tarnish/rust which will cause the circuit to overheat, which blows the fuse. Also check the wiring harness. (gas is a corrosive) That shop must've just wanted to get you on your way..
@chaseando16 I would only replace the pump IF it tested bad.
@hixster the shop said they checked the wires
@hixster It blew again. I replace it 4 times before I found out it was blowing just by turning the ignition forward one click.
It blew again. I replace it 4 times before I found out it was blowing just by turning the ignition forward one click.
@hixster It blew again. I replace it 4 times before I found out it was blowing just by turning the ignition forward one click.
This video below covers changing the fuel pump on an 03 Regal. As I mentioned above, you don't necessarily have to replace the pump assembly unless it's bad. It could be only your sending unit has gone bad. You have to find/fix what's causing the short at least.
Odds are a new pump fixes it. I just want to know what's wrong before I go replacing something. The first (highlighted) comment is someone with a similar problem as yours.. only the fuel level sending unit was replaced.
(don't take any tool tips from this!)
https://www.youtube.com/watch?v=X4q0vzexdcg&lc=UgzQjQSGYV3i47h0ofx4AaABAg
@hixster I did some research and decided to remove the related relay then try clicking the key forward. the fuse didn't blow like it had before so my research suggests it was a bad relay. I also had the fuel pump unplugged during this and it did not blow (but did when the relay was still in). Research suggests it is the fuel pump then. Is this enough evidence to throw the part at it?
@chaseando16 Climb in the trunk, remove the access panel and disconnect the wiring connector. Test just as @jack62 suggested and you'll know whether you have a short in the pump assembly
@hixster I waited a day and installed the fuel pump fuse, relay, and hooked up the fuel pump connector. started right up. I am leaning towards a fuel pump because last week the shop just replaced the fuse after it cooled off overnight and problem was solved.