Help Diagnosing Fuel Pump Issues on '03 620ie

[rrover454]

Hi all,

Trying to track down why my fuel pump is currently not working.  I went and bought myself a multimeter to measure the power/resistance to/for the pump, and this is what  found:

I measured about 1.95 volts at the power wire that connects to the fuel pump at the base of the tank.  The other wire for the fuel light was getting 10.9 volts.

I then measured the resistance for the wiring coming off of the fuel pump.  The wire for powering the pump produced no reading on my machine ( 0 OHM) while the wire for the fuel light was at 4.33OHM.

I tried jumping the pump from the battery with no result.

Since I'm not as electronically knowledgeable as I'd like to be, could someone be able to interpret my results?  It appears that the pump is in fact getting power, but is 1.95V too little power?  What would be causing this?  Does the nil resistance reading at the pump wiring mean the issue is at the pump and not the relays? (not being able to jump it is a good sign of that, I suppose).   Just trying to determine if I need to just replace the pump or also take a closer look at the relays.  Thanks!

[ducpainter]

The problem is either the pump or the sender where the wiring passes through to the pump...I'm thinking a broken wire.

I'm not sure why you're only reading 1.95 volts.

[rrover454]

That would make sense.  On the '03, does one have to pull everything out through the bottom or does some work have to be done through the gas filler hole?

[ducpainter]

That would make sense.  On the '03, does one have to pull everything out through the bottom or does some work have to be done through the gas filler hole?

The pump is removed from the top.

Once disconnected from the pump the sender and pump wiring is removed from the bottom.

I'd pull the pump and see if a 12v battery will run it. If yes it's the sender. If not it's the pump.

[rrover454]

Thanks very much, ducpainter.  Appreciate it.

[rrover454]

OK, so I've removed the filler gap and taken the fuel filter out of the way.  I can see the fuel pump but can't figure out how it is removed from the tank.  Any pointers appreciated!

[ducpainter]

OK, so I've removed the filler gap and taken the fuel filter out of the way.  I can see the fuel pump but can't figure out how it is removed from the tank.  Any pointers appreciated!

You reach in and push it up towards the top of the tank.

It's in a rubber sleeve which is in a spring clip type U saddle.

[rrover454]

Got the pump out.  First connected it to a battery and it didn't run.  I then tapped it with a hammer, and it came back to life!  Guess it seized since it was sitting for a while.  Connected the pump back up to the wiring, and it turns on when I turn the key.  Thanks for the help!

I now, however, have discovered another issue.  I can see that there are some pieces of mesh at the bottom of the pump.  If I remember correctly, there's a mesh bladder that is attached at the end of the pump?  I'll have to drain the tank and fish it out and replace it ( I need to get new fuel in there anyway).

[ducpainter]

Got the pump out.  First connected it to a battery and it didn't run.  I then tapped it with a hammer, and it came back to life!  Guess it seized since it was sitting for a while.  Connected the pump back up to the wiring, and it turns on when I turn the key.  Thanks for the help!

I now, however, have discovered another issue.  I can see that there are some pieces of mesh at the bottom of the pump.  If I remember correctly, there's a mesh bladder that is attached at the end of the pump?  I'll have to drain the tank and fish it out and replace it ( I need to get new fuel in there anyway).

If the pump required a 'tap' to run...

I wouldn't run around like that...your choice. I guess if you use it daily it will be OK.

You need to attach the screen to the pump.

[rrover454]

Thanks, DucP.  I'll order a new screen and possibly a new pump. 

[Speeddog]

If the hoses look suspect, replace 'em.
Use only OEM or 30R10 (immersion) rated hose.
30R9 will work for a short while, but will die due to being constantly immersed in gasoline.

New filter would be a good plan also.

[Howie]

 A new pump would be best for relaibility.  Definitely install a new filter and screen.  Since so much is apart.  Reverse polarity on the pump can eject debris if you want to try and save the pump. 

[rrover454]

Thanks, all.  I'll definitely go ahead and replace the filter, as well.  Hoses look ok.  Thanks for the reverse polarity tip.  Hadn't thought of it but was wondering how I could clean it out while it was out of the tank. 

Essentially, the bike has sat for a good while, causing it to seize up.  I'm just getting to sorting out the pump issue and will see if fixing this bit will get her to start.  If not, I'll move on to the next issue.  If I can get her running, I may consider just throwing a new pump in there for piece of mind..

Thanks all for the great help. 

[ian48th]

I recently had a broken wire fixed on my bike - AFTER replacing the fuel pump, filter and hoses inside the tank.  Hopefully you won't have that problem.

In my case, I think I put a zip tie around the wiring harness near the steering head that caused tension on the wires when turning the front wheel to the left and the fuel pump wire eventually broke.