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Happy Wanderer
04-04-2010, 07:17 PM
I have been working on my 96 R1100RT for a couple of weeks now trying to purge the surge with no luck. The last thing I did yesterday was put in new Autolite 3923 plugs knowing full well they would not fix whatever the problem is but I wanted to check that off the list. Once done I rolled the bike out of the shed and fired it up. As it was warming up I backed off on the "choke" lever to lower the idle and she just coughed and died.

Now what ??? I wondered. :scratch Started checking things and to make this short(er) it turns out the fuel pump decided to just die coincidentally after changing plugs. Weird but nice of her to do it just outside the work shed I suppose.

An old post by flyboyscd was really helpful in debugging. I should mention I know it is the pump because after making sure it was the pump and pulling it out I also hooked it up direct to the battery and you can feel it sort of click and stall. It is stuck or just broken and will not spin. I might cut it open just for fun but as I took the filter sock off I found a small piece of brown plastic in the pump inlet. A few more bits of plastic shrapnel were in the filter sock too. Hmmmm... this is not good says I. http://tinyurl.com/yh6fzom

I siphoned what was left of the gas out till I could inspect the bottom of the tank and found there was a much longer shard of the same plastic in there along with other really small nasty bits including a very tiny shard of some metal. I got a nice clean rag and sopped up the little bit of gas in there and cleaned the bottom of the tank thoroughly. http://tinyurl.com/ylkt9k3

BMW wants over $300 bucks for the pump so I hunted and found this OEM replacement from Euro Motoelectrics for $139. http://tinyurl.com/yhzgrj5
http://tinyurl.com/yhzgrj5
The original pump has screw post connectors and the replacement comes with push on connector tab style wiring so a bit of soldering will have to be done. I hope this pump works and fits well. I do wish they would have included new screw clamps because obviously they will be needed.

I looked at the wiring and assembly of the fuel pump and filter unit and understand all that pretty well but inside the tank there is a part I am not sure of. Maybe someone out there knows. There is a long metal tube with a spring inside of it that attaches to a plate at the top of the tank and goes all the way to the bottom where you can see that spring inside the tube . There are two blue wires attached to it with a cable tie that go to a connector on the fuel pump assembly. http://tinyurl.com/ycnptol

My questions are:
- What is that tube for?
- What are the two blue wires for? Is there a switch of some kind in there?
I thought the fuel float and wiper was the only fuel measuring parts in there but now I wonder if that tube and plug are also for fuel measurement. :dunno

I plan to reassemble using normal screw type fuel line clamps. If anyone out there has any tips or advice for me on re-assembly so I don't have to take it apart again that would be much appreciated!

Meanwhile, I will keep scouring the forums and learning. :lurk

norton
04-06-2010, 09:25 AM
The tube measures the amount of gas in the tank, while the float arm is for the low fuel light. Check out the following link. http://www.bmwmoa.org/forum/showthread.php?t=2411

Happy Wanderer
04-06-2010, 02:16 PM
Thanks Norton! I figured from the wiring I found in there the tube and float items were related so it had to be a level sensor of some kind. Now I know. The link you posted however is for some guy who joined the MOA in 2004 and was saying "Hi" in the club forum. Must have been a typo.. :type

I did some more searches on the keyword "Float Arm" I found in your post and learned a few more things. The float arm is delicate, (do not bend) prone to bad readings due to gunk on the wiper and is for the low fuel light only. The tube is for the RID fuel level display and it is not that accurate apparently.

On my bike I have noticed the low fuel indicator comes on rather early with one bar still showing. After the last fuel bar disappears I can still ride a lloooonnnnng way before filling. I found this out accidentally in Northern California last year and although I don't know just how far I can go with the light on I know it is more than 40 miles after the last bar disappeared. I was glad I reached a station that time without finding out just how far is too far.:doh

I also learned it is bad to do this since you risk losing prime on your electric fuel pump and also risk over heating and ruining the pump. I try to avoid low fuel situations as a rule but hey, it happens..

Happy Wanderer
04-08-2010, 07:41 PM
Installed the new fuel pump this morning and the RT fired right up. I highly recommend Euro Motoelectrics in Golden CO for after market BMW electric parts. (Thanks gsaddict!)

Order placed on Easter Sunday, shipped Monday am and arrived in Pt Roberts WA in two days on Wednesday. Awesome service. Also, they respond to queries very quickly by email.

I also bought a new spark wire set and the quality is excellent. I believe these are made by the same manufacturer BMW uses for wires with the BMW name on them. Only these cost $49 a PAIR. Also bought a six pack of Bosch Premium oil filters for $39. When you compare price and quality compared to BMW Canada it's a no brainer. A BMW fuel pump from my local dealer is over $400! That is over $100 more than a US BMW dealer and three times more than after market.

It's a gas pump for cryin out loud. Why we get the shakedown by BMW for wear items even with dollars at par now is beyond me.:banghead