1990 Q45 no fuel r+r fpcu

[doninfla]

what a great place for info on Q. ok i've read all the posts re: fuel pump+fpcu. mine was a strong burning smell. i actually thought it might be the rear bose speakers- shut off the radio. she got me home then died- no fuel pump hum after restart.,dead. thanks to the great posts i removed both pump and fpcu somewhat easily. my fpcu had totally melted the connector plug @ the white wire and unit itself burnt a hole in it's circuit board. replaced both w/94 Q parts from a yard. reassembled w/new(used)parts. pump hummed ok but no start..no fuel. R values on both pumps are ~.5 ohm. i want to jump the fpcu ground per posts. is it the black wire on fcpu harness to body ground? any possibility w/ all the current draw there are other potential circuit/ wiring problems? i miss my ride.. 1990 Q45 pearl/white. trans replaced 2x. now 1 year w/cooler. any help is appreciated !!

[3Q Jay]

yeah, harness to ground. pin 8 i think--don't remember the color.

welcome to NICO, you get points for searching first--well done.

there is also a green relay by the power antenna you might verify.

[elwesso]

Yeah i've seen this before, the fuel pump ground is kinda bad, especially if you have a failed FPCU.... You might run a new ground wire ...

[doninfla]

thanks guys - i'll try suggs. and get back.. but in my world 2-3 days goes by without time to squat.... so till then !!

[doninfla]

hey- i'm still on it got out my original and tried it in water. it hummed but no juice so gave it a rap on top and it squirted brown then ran clear for 2-3 minutes. reassembled, put in car and no start yet. looks like another week or two. any suggs? relay tested fine. now when checked the used pump from the yard by same method it didn't pump at all but hummed. hope to return that one....more later . thanks to all!!

[Q45tech]

Used corroded internal rusted pump from a junk yard? When water and corrosion caused your first pump to fail.

[96Qowner]

As long as you have it out of the car, you might try cleaning it up. Texasoil had great success with his:

"I took apart a 'noisy' but working fuel pump (135K) to see what was causing the noise. Found a small amount of 'rust' or corrosion on the tip ends of the spyder holding the rollers. Just enough corrosion on the tips to rub the cage at the close spot. No other wear of any kind anywhere. It would have gone at least another 200K miles in my opinion."

zerothread?id=73822

"I have a couple of good extreme close-ups of a disassembled Q45 fuel pump that clearly shows the source of noise. The pump is supremely robust and exquisitely designed. Noise is incidental"

zerothread?id=71411

[Q45tech]

EXCEPT the noise is a function of the rpm slowing down which increases the FPCU CURRENT................unless you return the rpm to as new the FPCU fails from overheating.

No other wear of any kind anywhere. It would have gone at least another 200K miles in my opinion." ????? AFTER IT WAS REMANNED/Cleaned up.