Hey guys. Is it normal to hear the fuel pump run while the truck is running? It is making the same noise it makes when you turn the key on and it primes for an engine start. It is so weird because tonight after I put my new driving lights in, I could swear that when I turn the headlights or the new lights on I could see the voltmeter twitch within a space of 2 notches and hear the pump motor change pitch a little when the lights are on. Tonight when the truck was stopped, the voltmeter was twitching back and forth when the turn signal was on. I already know my battery is low because of the frequent short trips and the frequent starts just to drive either 2 miles or 5 miles (small town) and the voltmeter was only at around 12-13v tonight after I started it up after being below 12 after testing the lights for a while and turning them off (it did however go to just below 14 when the engine was above 1000 rpm). Is my alternator or fuel pump screwed? No battery light and the car starts fine every time, but is this a warning sign of early failure? Also my serpentine belt and Duralast Gold battery are only 15000 miles old and my fuel filter is only 1000 miles old if that matters. Thanks for any advice.

 

You may want to check your grounds. Bad grounds can cause all kinds of strange things to happen. My daughters car had flickering head lights when she put on the turn signals or when her sub would hit, sometimes that gas gauge was not reading properly. I undid all the ground points under the hood and we have had no further electrical issues.

This would be a very cheap place to start your troubleshooting.

 

Where are the grounds that I would need to check? Because my gas gauge is not working properly either. Should I be upgrading the wiring with higher gauge wire?

 

The gas gauge not reading correctly is it's own problem. You need a new sending unit.

 

It's not the grounds. It's the alternator. I went to Advance Auto to get new battery cables and I had them test the alternator. They see a ripple in the alternator and they said it is starting to wear out. I am ordering another one tomorrow.

 

Speaking of the fuel pump, does being able to hear it when the engine is running and the bad gas gauge mean that the pump is going to fail soon? It starts up fine every time on the first try, though. The truck only has 88,000 miles and the fuel filter has been changed every 15k since I bought it at 58k and I rarely run it under 1/2 a tank, never below 1/4 of a tank.