novajoe said:
Any further info on this? Did you find the problem?
Today after a five hour drive my fuel pump started to make the warbling noise during the prime only. (130+K miles on pump) Fuel pressure is good so the pump is working. I am just checking to see if there is anything else that may cause this or is it just the first signs of a dying fuel pump.
You know what? I never did find out. As a matter of fact, I ran it for about four hours on a cool day last September and not once did it make the warbly noise. Same as you, fuel pressure was fine and no performance issues.
I wanted to try and measure voltages on the pump (to rule out faulty wiring), but never made it that far. I was also wondering if it was some sort of venting issue since it only happened on hot days-but that is pure speculation...I am not a mechanic or even probably familiar enough with the system to make that statement; just my personal thought.
The only advice I can offer after spending a lot of money having a mechanic look at it (and it was only half done, since the issue was not fixed and they did not troubleshoot) and watching May03LT's videos and reading posts are:
1)The pump has 130K on it, it's probably time to replace it anyway.
2)Get an OEM pump.
3)Make sure the mechanic troubleshoots the issue and doesn't throw parts at it--check wiring, measure voltages, and anything else they can do with the tank off since you already paid the labor to have it removed.
![Smile :smile: :smile:](/forums/smilies/smile.gif)
4)Maybe replace the fuel filter, too? Especially I think the later years, the filter is a lot harder to access?
I am sure someone might offer something a little more useful, that's just my experience and I am not a mechanic. Good luck it was frustrating. I ended up trading it in for a Ford Expedition....I already miss my Trailblazer...it seemed more comfortable and I have already paid to rebuild the rear differential, a rear wheel bearing and front axle seal. Plus, it has a bunch of other minor "known" issues I need to fix someday....and my biggest fear....Spark plugs--it's a 2005 and I guess that 2nd gen 5.4 engine is known for plugs getting stuck in the block, yay!
If you do find a solution, I'd be curious to know what it is.
gunrock