Hey Guys
A few weeks ago I heard a whine coming from the fuel tank, definitely from fuel tank. Put my ear on bottom of tank while whining and can hear and feel the vibration. This is not a prep whine, almost a screeching. The whine went away and returned. It comes and goes. Quality of gas should be fine. Gas cap is good. No codes. No other problems besides the strange slightly rough/loopy idle it has had since I bought it. Getting ready for a trip and paranoid about this noise. I know it had a fuel pump replaced a couple years ago before I bought it, probably with the cheapest pump the shop could get their hands on. What do you think? Is the pump likely beginning to fail? Should I replace before trip or run a few diagnostics? Any info I can provide to help please let me know because I am lost. Thanks in advance.

 

Better safe than sorry. Went ahead and ordered replacement. Found good deal Delphi pump + Delphi Filter = $286 shipped after coupon at autopartswarehouse.

 

As long as Ive had my Blazer I noticed the fuel pump is loud. I was worried about it for a while. Now Im just used to it. Get better speakers. You'll never hear it again.

 

Haha. Forgot to mention it was a 2001 Jimmy. Guess that might have helped. Its not the noise that bothers me, its the fact that it showed up unannounced. Speaking of speakers. The rears do not work. Apparently, tons of people have a problem with the rears not working. Put in new speakers and all is good, move "bad" speakers to another stereo and to amazement, they work???

 

fuel pumps can and will whine especially if you buy cheap ones... some people do think if they whine they are goin bad and that isnt 100% correct... my brother put one in a 74 chevy super cheyenne when he converted it to tuned port injection and was the LOUDEST pump i ever heard but it never went out or lost pressure... and FYI i have the part number for a AC-DELCO fuel pump rebuild kit that only cost $60 that has pump,lines,socks and updated wiring for 2nd gen blazers

 

I would like to get that part number. The only thing wrong with my pump was worn brushes.

 

Delphi Mfr #: W0133-1599177

 

Hey Guys. Took pressure readings and unsure about results. Please bear with and read to the end because the last set is what worries me.

Initial Connection, truck not driven in a couple days. 0 PSI

Prime Pump
7:05 60 PSI 7:08 55 PSI 7:10 55PSI 7:15 54 PSI 7:20 53 PSI
7:25 51 PSI

Start 700RPM Idle
7:25 54 PSI Steady

Accelerate and decelerate rapidly
7:27 Upto 60 PSI down to 52 PSI settles at 54 PSI all instantly throughout the rpm range

2000 RPM
7:28 52 PSI Steady

Shut off engine
7:30 From 54 PSI while running upto 62 immediately after shutoff, can hear relay click and pump stop, immediately settles at 58 PSI

Bleed to 10 PSI
7:52 10 PSI
7:53 12 PSI
7:54 13 PSI
7:55 - 8:07 14 PSI

Here is the last one. Started up after the last set and the needle on the gauge was NOT steady it was jumping so rapidly it was just a blur. I could slightly hear the pump but not nearly as much as the whine I sometimes hear.

8:10 Needle jumping between 54 and 56 PSI
8:15 Needle jumping between 52 and 58 PSI
Needle still holds 52 PSI steady at 2000 RPM

Ran vehicle for a while to see if I could see what the pressure is doing when the pump is whining, but of course, it did not happen.
THANKS FOR READING GUYS, appreciate the help.

 

I believe the elctrical connector on the fuel tank had a habit of failing. It would not provide a good connection. So if the connector is loose, corroded, burnt, arcing the pump may not be getting full voltage. No juice in means no juice out!