Brand new ACDelco EP381, just installed on a 3800 L36. I replaced the tank gasket as well, made sure that it sealed properly. Also just did darth's fuel pump hotwire where I used a 20 amp fuse(should it be higher or lower?).

The fuel pump is so loud. I can hear it over idle and basically all the time, the only time I cant hear it is on the highway with a full tank of gas(sometimes I still can). It sounds like one that is about to go out. Car runs great, has plenty of power..whats the deal? Am I just cursed being able to hear it because it is right next to you in the car?

Did you install the pulsator? Ir is it connected straight through a piece of tubing. Th pulsator might make the difference.

My Duke fuel pump sounds like a Cessna, but it still works just fine. My 84 SD (carbed) was the same way, and it was a brand new AC Delco pump.

I replaced my original pump (2.8) with the ACDelco EP381 in preparation for the 3.8sc swap and it's quiet as a mouse. Maybe you got a dudd.

Spoon

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"Kilgore Trout once wrote a short story which was a dialogue between two pieces of yeast. They were discussing the possible purposes of life as they ate sugar and suffocated in their own excrement. Because of their limited intelligence, they never came close to guessing that they were making champagne." - Kurt Vonnegut

quote Originally posted by Raydar: Did you install the pulsator? Ir is it connected straight through a piece of tubing. Th pulsator might make the difference. My Duke fuel pump sounds like a Cessna, but it still works just fine. My 84 SD (carbed) was the same way, and it was a brand new AC Delco pump.

I just installed it as it came. Picture here . Is that wrong?

I don't mind the sound, it just worries me that it will go bad.

I buy all electrical stuff (fuel pumps, starters, alternators, etc) from Napa. It may cost a little more vs. eBay, Rock Auto, or Amazon, but it helps weed out the knockoff stuff.

I like my fuel pumps to be whisper quiet...

My EP381 is installed just like yours, with no pulsator. I have to watch the voltage gauge to see if it's priming. Extremely quiet. I fear you may have gotten a knock-off. I had to return one I got on Ebay because it was not as advertised. With a FP being such a difficult install, it's worth a few extra bucks to be sure it is an original.

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'87 GT , '00 3800 Series II SC, 4t65e, Vue Power Steering.

Whats it sound like? Nice clean high pitched buzz like a fuel pump should, or a grow or grind, does it waver in sound, etc?

quote Originally posted by Threedog: I just installed it as it came. Picture here . Is that wrong?

Looks okay to me. (Some cars had pulsators. Others didn't. I used to think I knew which, but apparently it's a crapshoot.)

quote Originally posted by Raydar: Looks okay to me. (Some cars had pulsators. Others didn't. I used to think I knew which, but apparently it's a crapshoot.)

My 88 (Formula) did, my two 86's with dukes didn't.

quote Originally posted by 2.5: Whats it sound like? Nice clean high pitched buzz like a fuel pump should, or a grow or grind, does it waver in sound, etc?

It's a consistent, high pitched noise that changes pitch with the revs. I'll see if I can get a video of it later.

I'm just thinking with a sound like that it may not be that unusual.
But... if its so loud it is annoying you would want to change it anyway.

Video is here. Watch through the whole thing, it gets louder at the end.. I really don't want to drop the tank and replace it again, but I will if I have to. I have a two hour drive on Saturday for memorial weekend and I do NOT want to get stranded.

Mine is loud but only when the tank is near empty. It is the original, as far as I know. Since I need to replace the sending unit anyway, I planned on replacing the pump.

In doing research, it seems these things are a crapshoot. Whether AC Delco or another brand, seems like some say theirs are loud, others not. I don't remember ever hearing my fuel pump when I owned these cars in the 90s.

Worse yet, seems to be varying opinions on whether a loud pump is an issue. Conventional knowledge says loud fuel pumps are about to go out, yet it seems folks here say they are often loud with no consequence.

I bought an AC Delco pump for the change -- they are inexpensive now from Autozone. But haven't changed it yet, and threads like this make me worry I'm gonna do all that work pulling the tank only to have an issue with the pump when its back together.

I did buy a new pulsator though, if that matters. Seems like there are many differing opinions on that, too.

[This message has been edited by USMUCL (edited 05-25-2017).]

That high pitch is weird, Id change it.

So I played around with it and mostly fixed it. I noticed that the pump was only loud when the car wasn't under load. This, to me, meant there was an issue with the return line.

I took the tank out, replaced the pump gasket and it is almost whisper quiet now. However, I do not think the gasket is what fixed it. I also made sure that the rubber "holders" on the three lines were in the original places. Additionally, I wrapped the feed/return line on top of the tank in some old coolant hose. When the tank was originally removed, the lines were slightly bent upwards, which meant that they pressed against the top of the tunnel. Since I added a rubber barrier in-between the lines and the tunnel(the coolant hose) the noise doesn't make it through.

I think the problem was that the lines were making contact with the tunnel, making the noise from the pump reverberate through it.

quote Originally posted by Threedog: Additionally, I wrapped the feed/return line on top of the tank in some old coolant hose. When the tank was originally removed, the lines were slightly bent upwards, which meant that they pressed against the top of the tunnel. Since I added a rubber barrier in-between the lines and the tunnel(the coolant hose) the noise doesn't make it through. I think the problem was that the lines were making contact with the tunnel, making the noise from the pump reverberate through it.

Could be, originallty they had rubber separator / holders, maybe yours are missing?

This is interesting. Makes me wonder how many others, who report loud pumps that are virtually new, were actually hearing the vibration of the lines against the tunnel or tank.

quote Originally posted by 2.5: Could be, originallty they had rubber separator / holders, maybe yours are missing?

I had them, but I didn't think much of them and pushed them really far down the pipes towards the end, and that was the problem.
I think.

Are you sure that pump was a real AC Delco? If you look on eBay there are tons of " geniune AC Delco" EP 381 fuel pump selling for as low as $30. A good many are low quality Made in China counterfeits. That's why I've switched over to using Bosch 69225 fuel pumps and they are of a turbine design that don't pulse like the gyrator design. Apparently the counterfeiters don't feel copying that brand is yet worthwhile.

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" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

quote Originally posted by Dennis LaGrua: Are you sure that pump was a real AC Delco? If you look on eBay there are tons of " geniune AC Delco" EP 381 fuel pump selling for as low as $30. A good many are low quality Made in China counterfeits. That's why I've switched over to using Bosch 69225 fuel pumps and they are of a turbine design that don't pulse like the gyrator design. Apparently the counterfeiters don't feel copying that brand is yet worthwhile.

I don't think cost is an indication of fake AC DELCO - I just bought mine straight from Autozone for $25. I hate Autozone quality in many things (most Duralast items), but I doubt they are selling counterfeit DELCO products

[This message has been edited by USMUCL (edited 05-27-2017).]

quote Originally posted by USMUCL: I don't think cost is an indication of fake AC DELCO - I just bought mine straight from Autozone for $25. I hate Autozone quality in many things (most Duralast items), but I doubt they are selling counterfeit DELCO products

Well.... Their website says AC Delco EP381 is $95. Who knows, maybe they did get a batch of counterfeits.

quote Originally posted by USMUCL: I don't think cost is an indication of fake AC DELCO - I just bought mine straight from Autozone for $25. I hate Autozone quality in many things (most Duralast items), but I doubt they are selling counterfeit DELCO products

A price of $25 for a new AC Delco EP381 fuel pump sounds very suspicious. There must a way to tell the counterfeit from the originals but the fact that the OP's fuel pump is whining, tells you that something is just not right. Remember the flood of counterfeit Walbro pumps that came in a few years ago. They caused al kinds of problems for the company that made the genuine article. There were failures all over the place and the fake pumps even had the Walbro trademark stamped on the case!!!
good article: http://www.acdelco.com/counterfeit-auto-parts.html


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" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

[This message has been edited by Dennis LaGrua (edited 05-27-2017).]

Sorry -- I probably should have specified that I went with the stock replacement for a stock 2.8 car, which is the AC Delco EP240, right? If that is wrong, TELL ME NOW BEFORE I INSTALL IT, LOL

That kit is only $21.69 at Autozone. I know this is different than the OP's requirements, but I also suspect it is much cheaper than the AC Delco replacement used to be. And unlikely to be counterfeit given it is coming from a large retail vendor.

Now whether the AC Delcos are really any better than others, or simply rebranded cheap aftermarket is a different conversation

[This message has been edited by USMUCL (edited 05-28-2017).]

A fuel pump is obviously a critical automotive component. It must work continuously for hours on end. To do so rock solid reliability must be built into the design. Nothing new with this comment but the point is that major companies like Bosch & AC Delco set stringent quality standards. They have to as their parts are used in automobiles that are guaranteed for 5 years/50,000 miles or at the least 3 years/35,000 miles. In China few such quality requirements exist. The manufacturers range from large modern facilities to small mud huts where slave labor is used. When you decide to buy Chinese, you never know what quality standards if any were applied to the parts that you are buying and there is no law against importing junk. At my local Autozone, two full pallets of defective/returned parts are sent back every month. Look online at the horror stories of failed brake rotors.

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" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

If it means anything, I bought it off Amazon and it was a genuine ACDelco.

quote Originally posted by Threedog: If it means anything, I bought it off Amazon and it was a genuine AC Delco.

Amazon is a resale service. The warehouse distributor who resells the fuel pumps would know for sure. If you in fact purchased and installed a genuine AC Delco pump then why the whine? You say its "so loud" That's not normal .

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" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

quote Originally posted by Dennis LaGrua: Amazon is a resale service. The warehouse distributor who resells the fuel pumps would know for sure. If you in fact purchased and installed a genuine AC Delco pump then why the whine? You say its "so loud" That's not normal .

The seller was Amazon themselves, not a third party.

Regardless, I posted the solution I found above. Same pump, same connections, whisper quiet now.