AWR-fix: Siphon pump repair

[270_BMW]

Originally Posted by wpoll

I think it's the latch (head) on the zip tie that is doing the job here. It stops the lower section moving up (pivoting) and sitting wonky....

That’s what I was thinking. So it needs to be tight enough to keep the head in the gap. Wouldn’t it be better to move it to the other side?

[wpoll]

The further the "stopper" is from the pivot point, the more effective it is.

[andrewwynn]

I did position the head opposite from the fulcrum for exactly that reason. I wasn't sure if the main body of the tie was thick enough to not fit into the socket.





You can see that it actually holds tighter than straight. I am ok with that as once operating there will be torque from the gas pressure pushing to straighten it out.

[270_BMW]

SCIENCE!

Lol. Thank you guys for clarification. Sorry to ask so many questions just wanted to make sure I was on the same page.

[ahlem]

Thanks for this thread.
I changed the O ring and was testing to see if the siphon pump worked properly now. As it turns out, it was. I ran out of gas on an off ramp today near work. Between the 3+ gallons from the red gas can a guy from work brought and the 22 gallons at the station down the road, I proved it runs all the way to empty. I just need to figure out why my level indicator stops and sticks just a shade under 1/2 tank so this doesn't happen when it's in the middle of a snow storm. I had the transfer pump side pulled up for a bit when I fixed the O ring and possibly got the level sensor arm twisted or caught on something in the process of putting it back in?

[andrewwynn]

My fuel gauge got stuck at about 3/8 of a tank. It was from the sending unit on the left side reading high. I have a how to on XO to fix it yourself. The spring part of the wiper is not pushing hard enough on the resistive surface.

Search awr-fix in the title and you should find it. It's not a difficult fix. I found a BMW service bulletin on how to tweak the resistor wiper. I only saw it once and couldn't find via Google so it was all from memory but it worked like a charm my sending unit snapped into action and has been working perfectly since.

[ahlem]

I found the other post. Nice write up.
I'll check the sending unit. My first guess is that I bent something or that the float arm popped out of the wiper bracket rather than the wiper itself. I do have 1000 grit wet or dry paper. Personal experience here on a similar repair to an e46.
In that case the float arm popped out and was pivoting at will. I'll wait just a bit because when I filled the tank after the event, I topped it off to see how far down I was when I ran out of gas. Bone dry I'm pretty sure.

[andrewwynn]

You can tell when you are about to run out of gas by watching test six. The right side will stick at 014 or so until both tanks are depleted. Once that starts to drop you have about 3.6L of gas and can go maybe 10 miles before a walk with a gas can is in your future.

[ahlem]

I didn't put teflon tape on the non O ring seal. Is that why the test 6 results show 020 to 000 on the right side as the fuel sloshes around? 020 on left hand turns and 000 on long sweeping rights. The left side is reading 027 +/-

[andrewwynn]

Once below 28L or so total the right side effectively is empty. It should register about 1.4L on level ground.

When you accelerate or turn all hell breaks loose with the floats thats why the dash uses a buffered value.

A firm right turn will spill more than normal fuel from right to left and can eaisky register 000L for a bit until the siphon jet sucks some fuel from left to right.

If on level ground the right side drops lower than the 1.4 ish, then you have siphon problems and need to address it.