i understand this is an old topic, but could someone give me an answer if there is one?
i drive a 1988 IROC-Z and i replaced the fuel pump fuel filter and fuel sending unit.

Problemn a warmer day after driving around for about 30m-1hour my fuel pump will eventually become so loud i can hear it over my pipes. if i continue to drive eventually it will cause my car to shutdown.

Before there was crazy amount of pressure in the tank. but i took off the ventilator check valve under the car near the fuel tank. now my car drives longer before the fuel pump screams. however, there is no pressure build up in the tank and the pump still gets loud.

if there is any solution that helped you out please let me know because summer is coming and id like to drive my camaro around.

 

I'd love an answer to this too lol. Just had my pump, regulator, and injectors replaced because the pump was squealing off and on. well, the new pump is a constant hum, and after about 30-1hr of driving, it gets loud enough to drown out my exhaust. haven't had it die yet, but I'm just waiting for it. There are plenty of threads to go over if you want to find possible solutions, but I don't think this has ever been definitively solved yet. Have you checked your fuel pressure before and after the noise starts? that's a good first step. You can rent the gauge for free from auto zone.

 

I'll check that tommorow and I'll let you know. Since I've taken the ventilator off it has stalled on me yet but I havnt drove long enough for it. What I gathered from the threads are that the headers are causing the hose which carries the gas to the block is getting very hot and "boiling" the gas. Or the exhaust doesn't have a heat shield and it's cooking the tank like a pot of water. So heat shield on headers and exhaust is what ima try this weekend.

 

Yep good stuff to check as well. Not my problem unfortunately. Headers are heat wrapped and ive got my heat shield intact. What worries me is that it didnt start to whine till I got my new exhaust done. Im wondering if the heat shield isnt enough to keep the fuel cool for some reason. Im curious, does an aftermarket muffler possibly get hotter than a stock one?

 

im not sure but i do have after market exhaust as well. but my buddy has a V6 that is all stock and his fuel pump screams eventually too just takes a little longer than my V8

 

Be sure that the power supply to the pump is providing a solid 12V. The relay contacts can become worn and burned and cause voltage drop. Also, poor connections anywhere in the fuel pump circuit can cause the same kind of voltage drop resulting in low voltage to the pump. Running the pump on less than 12V will stress the motor and cause it to fail prematurely. Be sure too that the ground circuit to the pump is good.

Use a DVOM to measure voltage drop between the pump circuit at the 4 pin connector above the tank, and the FP fuse by the battery. There should be no more than .5 volt drop with the pump running. If there is, check for volt drop across the relay, it should be less than .2v. Check and clean as necessary each connection in the circuit until you get below .5 volt drop.

If you can't find any poor connections and the relay tests okay, check voltage drop across each portion of the circuit between connectors. If you find one that has more than .2 volts drop, you may have a broken wire that needs to be repaired. Check the ground circuit for voltage drop. It should have less than .2 volts. If not, find and clean the connection to the body.

 

Well, looks like some success finally! this being the third pump to be put into my car in about a month, I told them I didn't want a delphi pump anymore, so they gave me a bosch instead. (this was after gm gave me my FREE gas tank for the recall) And so far, no noise at all! It has been a little cooler here in CO though, so we'll see what happens when it starts really heating up again. But for now, I'm reporting a tentative successful solving of my fuel pump whining problem.

 

I had mine replaced under warranty and it was doing really good but this week it's been about 95+degrees everyday and after about 1 hour I hear the pump. However it hasn't shut off on me yet

 

Alright well I'll just see what happens. Been a couple days now, and not a peep, but it's been a little cooler here. should be in the 90's today so I'll drive it a bit today and see how it goes.

 

Been pretty warm last couple days. mid 90's and been driving it quite a bit. No problems as far as fuel pump noises, but I did notice that I hear a bubbling noise from the tank when I prime it after the car is warm. kinda strange but I'm not too worried about it till I have problems with it. So far so good!

 

Glad to hear and I hear thAt bubble noise after driving around awhile then I just turn off the car I can hear it in the tank

 

mine goes away after a few seconds though, and I can't hear it at all when I'm driving. might be because my exhaust is kinda loud though haha. I think both firebirds I've had have done that though so I'm just gonna assume its normal.

 

its just the flux capacitor warming up, dont worry about it its normal

 

Good to know. Thanks Doc

 

but yea mine in my 85 iroc is just constantly loud, and i have an SES code for low fuel pump voltage?

dont really know why and am not to worried about it because the motors coming out soon anyways hahah

 

Man low fuel pump voltage, sounds like a wiring problem. I HATE wiring problems. such a huge pain in the ***.

 

i just find it odd that it ran FINE and had more power then ever, never gave us any problems as far as fuel related...... and its been that way for over a year... till i sold it and the kid blew it up and abandoned it on rt 30 and i bought it back i was pissed, but its ok my babys home safe for ever now, sporting her new interior and all new body work, trans and rear, shes waitin on a motor tho,

 

oh and all my wiring is 100% original, unmolested any where besides me fixing the radio harness back to factory....

 

fervernt - i'm in colorado springs too! My car was running FINE, but the sending unit was going. Replaced sending unit and fuel pump (hey, as long as the tank was out, right?) and now my car shakes, coughs, and the fuel pump sounds like a train whistle after driving it for at least 30 mins. we replaced with A/C delco ep381. (upgrade from ep241) I'm seriously considering going to the BOSCH unit, where did you get yours? and which one did you use?

 

Well. I just went into the shop today that did my fuel pump. They told me that they had put a bosch in. Well I went into the front office and talked to the lady at the desk and got the part #. I just now looked it up, and it's a carter fuel pump. NOT a Bosch. That effing shop can suck my left nut. I am so fed up with them. I haven't heard of carter before. I will say though, it does seem to be holding up much better than the 2 delphi pumps they put in. the part # is P74006 if you are interested. I also had my fuel tank replaced before they put this pump in though because it had a large crack in the filler neck. I personally think that's what was making the pumps give out. Does your tank hold pressure?

 

Hey guys, I never had a problem until my engine swap a few weeks ago. The car was parked for almost 4 years after the 305 blew up and after the swap to a 350 it wouldn't prime nor start of course. I replaced the fuel pump and after a few days I started to hear the infamous whine and have the other symptoms: fuel tank pressure, boiling sound inside the tank, and now it even dies on me when the car's hot, etc. I now the sending unit needs replacement because my fuel gauge isn't working now, and the plastic "bowl" inside the tank is all broken too. My tank was very dirty and I cleaned it the best I could but I don't know if that's causing this problem. Any help guys???

 

I know this is a little late, but I chased that fuel pump whine since I drove this car off the lot in 1992. I thought it may have been fixed when I took it to the dealer in the mid nineties to have them comply with a directive for a cracked filler neck, but it kept doing it.

I replaced the pump with a Bosch this year and haven't heard a peep since out of the pump. It's like magic. The Bosch pump kit also has a small bypass hose so you can get rid of the fuel pulsator (that tiny device above the pump that looks like a master cylinder reservoir). That did give me problems about seven years ago. The rubber hardens and the fuel pressure in the line will not hold, so it was taking two attempts to get the car started. Also, on hard acceleration, I think some of the fuel was slipping out the pulsator causing the fuel pressure to drop and the car to lose power. I replaced three ignition coils until I finally go to the leaking pulsator.

Anyway, try the Bosch pump. It totally solved the whine, the stalling when idling at a stop, and the gurgle in the tank after shutting down on a hot day.