about to put my 3rd fuel pump in and its only been a year. First pump was some junk from RA so i can understand why that went bad. But I replaced it with a delphi. 9 months have passed and now today the car won't start. Fuel pump would not prime up and I could not activate it through my scanner. banged on fuel tank and then it started working.

The harness to the fuel pump has been replaced last time I changed the fuel pump. I have notice for the past 1-2 years that everytime something electrical takes place in the car like putting the brakes on, using the power switches, condenser fan kicking in, that the lights dim briefly. I could also hear the fuel pump step down a bit while the car is running anytime I apply brakes.

So I'll take a wild guess that there's some kind of low voltage problem and maybe it's messing with the fuel pump. Interior lights in the car dim too when car isn't running and i step on brake or even hitting the power lock switch so it wouldn't be the alternator, would it? I've checked for loose, frayed, broken, bent, unplugged wires but not finding anything. I checked voltages at the harness to fuel pump when I put the first one in, two pumps ago and everything was where it should be.

any ideas or suggestions?

 

What voltage is the alternator putting out? VOM on the battery engine off reads battery voltage engine on reads alternator voltage. Battery should be above 12.6, alternator varies between 12.6 and 14 volts depending on demand.
Did someone remove/disconnect the piece of plastic that lives on the negative battery cable? That is the sensor that controls the alternator.
Any weird after market mods?

 

I will check the voltages tomorrow. No, no one removed the plastic piece on the negative battery cable. Assuming you are talking about the ring like thing that the neg cable goes through? I do have two amplifiers for the stereo but i've disconnected them in the past just to see if there was any difference and there wasn't. I have a hunch that battery may be the culprit and I know the amplifiers can wreak havoc on plain jane batteries. Battery is about 3-4 years old and it's just a wal-mart special. I will post back with voltages tomorrow. thank you

 

decided to check real quick when I got home from work. Car running voltage on battery varied between 14.5-14.6 volts. Nothing on except interior lights from gate being open. Car off the voltage started at 12.8 and I watched it slowly drop down to 12.44 within a 5 minute time period. Again, only thing that was on was interior lights.

the fuel pump that's in now (delphi) had been a bit on the noisy side from day one. Very high pitch whining kind of like a jet engine but it didn't sound like anything was wrong like clangy or marbles in a can. Just thought it was the nature of the beast and read that's how those pumps are. Always was curious about the slight interuption of that high pitch whine every time I put the brakes on or condenser fan would kick in. I can understand the condenser fan, but brake lights? do they draw that much?

anyways, 14.5-14.6v alternator seems high to me with just the car idling and no accessories running. what's calling for all that? Maybe the bad fuel pump, or what made the fuel pump go bad. Don't know. On the other hand, i would think a really bad voltage problem would have gave me less time than 9 months with the pump.

Good news is RA is giving me another under warranty so there's that but I kinda have a bad taste in my mouth for Delphi.

 

and while i'm thinking of it, I do have a dashcam that's wired into the 12v switched of radio harness. and my kid has a phone charger in the back 12v jack but i unplugged it.

 

14.6 on alternator is right. Something is draining the battery.

 

Lots to investigate, while you’re at it tighten those 4 bolts in the under hood fuse box, check ground wires, are they clean and tight?
good that RA provided a replacement fuel pump, before you go to the trouble to replace it, check the fuel pump fuse #13 and relay #19

 

Bolts under fuse box are tight, really tight! Grounds are all tight and clean. If I'm not mistaken, is there not a ground for the fuel pump behind the tail light or something like that? I didn't check that one.

As far as battery voltage, if the car is running doesn't the alternator just replace the voltage that is draining? In other words, would a low voltage battery be an issue if the car is running?

Wondering if that phone charger in the back seat is draining it. I'll have to unplug it and see.

This morning I put a meter on the battery again. Was at 12.3 volts. Fuse #13 good and relay #19 good. It's a new one but I have another spare I'll throw in anyways. Is it worth the trouble of buying and putting a new fuse in #13 even if it isn't blown?

 

Any chain auto parts store will perform a free battery load test. 12.3 volts it's probably toast

 

Agreed, my experience tells me it’s probably a dead cell