adjusted fuel pressure, pump failed next day almost? any input?

[281pony]

this past week i installed a new fuel level sending unit. i vacuumed the top of the tank, blew it off, wiped it with a rag, and vacuumed again. i NEVER came close to touching my fuel pump, not even the connectors off it. no dirt got in the tank swapping sending units.

so now, the second time i drove the car since i replaced the sending unit, the pump has a different sound when priming. now it has more of a "droned" down prime, i drove it 30 miles to my cousins place. it still kept the weird sound, then when i left today to come home, it sounds different again. sounds like someone gurgling underwater. now i know this sound all too well, the pump is struggling and will be failing me soon. my question is, WTF could possibly cause this failure? the tank was just thoroughly cleaned, all new components installed (injectors, pump, filter, ect), with the install of the pump not even 2500 miles ago.

the only thing i touched semi-related to fuel pump was my fuel pressure. i raised it to 50 psi with the car idling (is that vacuum off? never clarified for sure if that was vac. off). could/would changing the fuel pressure dump a pump like this? it is a 190 lph walbro pump.

so i am buying a new pump tonight, anyone think i should go with a 255 this time over the 190? its no price difference either way. would just like these damn FORD fuel pump issues to go away. my cousin had it too, his parents contour have it also.

 

[HISSIN50]

The pump puts out what it can and the reg sends the rest back to the tank. So the FP should not have had much to do with it. (stock spec is 38-39 PSI with the vac line off and capped).

I really dont have any great ideas for ya. The pump's pitch can change when the tank gets low on fuel, but you know that.

Good luck bud.

 

[Luvmy88]

put your old level sending unit back in -that will tell you one way or the other.

 

[Michael Yount]

Looking at your list of mods - mass air or speed density?

If mass air - the pressure should be left stock - 38-39 psig measured at warmed-up idle with the vacuum line off and plugged. There is no reason or perf. benefit to changing the fuel pressure if you have a properly matched maf/injectors/ecu.

 

[281pony]

its mass air converted. 24# injectors are a bit too small without playing with my fuel pressure which is why i have increased it a few times.

why would putting my old sending unit back in fix a fuel pump?

it is in the lower range on fuel. like 1/8-1/4 tank. i guess i can take it and get some more gas. i wasnt really planning to fill it up anymore though to drop the tank. ill siphon it out worst case i guess.

i knew about the return line, but it just didnt make sense for a pump to go bad out of nowhere with essentially only an fp adjustment to blame. the tank has not been under half for probably 8 months or more.

i never had a gauge to read it, so i always put gas in there just to make sure. recently i thought it was low after i didnt put any in for awhile. i got 4 gallons in and it was full this is the first time that fuel pump has been under half a tank actually since its been used, so ive never heard it at a lower level. it sounds damn weird though, ill see if my camera will pick up the noise.

 

[281pony]

update.

camera wouldnt pick up the weird prime. it was the same this afternoon still.

went in another car and put 4 gallons in the tank. primed it, sounded a little different, second prime almost normal sounding (steady pumping sound) but a little quieter, third prime it sounded normal except a little different initially.

so then i drove the car, it drove ok. i came home, took the vacuum line off the regulator, plugged it, set the fuel pressure. funny thing is, before my last adjustment it was set perfect with vacuum off. so its right back where it was before the pump issue.

i shut the car off, prime it. sounds normal again. second prime normal, third normal again. so for now it sounds fine, fp is back to where it was, tank is just under half.

i can ONLY come to the conclusion it was from a fairly low tank (a little over 1/8th) and adjusting that fuel pressure. this makes no sense at all.