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DIY: Replace Fuel Level Sending Units

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diy fuel pump
201K views 98 replies 67 participants last post by  Adarkane 
#1 · (Edited)
Fuel sending units & level sensors replacement

Here are the symptoms my car had that prompted me to replace my fuel sending units & level sensors:

1) Car died on the freeway even though CPU said I had 45 miles till empty.
2) Then it did it again even though CPU said I had 75 miles till empty a week later.
3) Car stutters while accelerating at full throttle, even in straight line.
4) Rough idle. When taking car out of gear coming to a stop, needle would dip below idle, sputter, rev itself back up, only to dip again and eventually die sometimes. I could fire it right back up, but just ANNOYING.
5) Poor MPG.

SO, I decided to replace both sending units/level sensors. I also replaced the fuel filter.

Fuel sending units & level sensors replacement:
NOTES: I AM NOT RESPONSIBLE FOR ANY DAMAGE. THIS IS SIMPLY WHAT I DID. WORK ON YOUR OWN CAR AT YOUR OWN RISK.
That being said, I had about 3/4 tank of gas in my car at the time. It's suggested that you wait till you are basically empty before you do this job.
HAVE A FIRE EXTINGUSHER HANDY. Although if my gas tank caught, I don't know what good the tiny extinguisher would have done. And finally, use your brain. You're working with fuel here, so don't smoke, don't use a working lamp that gets hot, etc.
Again, I am responsible for nothing, this is just documents of what I did.

1) Disconnect battery.
2) Open your gas cap.
3) Remove rear seat bottom by pulling up on the front edge of them and then lift the whole bench up and out. In the first pic, you can see the sliver tab on the driver side where it was holding the seat in. Just lift at that spot and it will pop off.
4) Lets start with the passenger side.


5) Lift the rubber grommet that seals everything up.



6) Now lift the big rubber flap covering the access panel. Remove the 4 nuts holding the plate in place.


7) Unplug the electrical harness. It's a sliding lock harness.

8) FIRST (1 on the pic), remove the hose clamp. This thing was annoying so I shoved a small flathead in the loop, pried it loose, and used a needle nose plier and just ripped it off. SOME gas will spill from this hose, so be ready with towels. I shoved a big bolt in the hose to keep it plugged while I worked. Replace the old hose clamp later with a standard, flathead-screw-closing hose clamp.
9) SECOND, (2) remove the ring that secures the fuel sending unit in place. To do this, place a flathead screwdriver on the raised ridge on the ring, and if you want, have a buddy do the same thing on the opposite side, and at the same time, both tap the screwdrivers with a small hammer. It will take a few good whacks to get this sucker loose. It only takes about half a turn to get this ring off. Turn in COUNTER CLOCKWISE direction to remove.


10) Once the ring is off, you will have to give the unit a good pull, but it will pop off. Stand by with a bucket to put this in as it's covered in gas.



There will be a rubber gasket that comes off. Replace it with the one that comes with your new pump.

11) Put the rubber gasket in place first. Then slide the new fuel unit in place. Push it in so it's all sealed and in tight. Replace the ring to seal it and hammer it back in place, opposite of how you took it off.


12) Re-connect the hose using a new hose clamp.
13) Re-connect the electrical plug.
14) Put the plate back, bolt it back up
15) Put the rubber flap back.
16) Put the rubber grommet back.
17) DONE. Move on to the other side. Drink a beer here. DON'T SMOKE anywhere near by. :)

OTHER SIDE (Driver's side)
Basically, everything is the same EXCEPT there is a connector on the bottom side of the unit that you have to pry off the old one and plug into the new one. Here are the pictures:
1)


2)


3)


4)


5)


6)


7) OK, here is the part that was connected to the UNDER side of the sending unit. You have to pry it off (one push tab connector and then used a flat head to pry it off. It's one piece)


8) Here's the new unit installed. Re-install the electric harness, the hose to the connector with a new hose clamp again, and finally the ring to secure everything.


9) Put the black top back and bolt it down, cover it all back up, put your seat back in place and you're done! Don't forget to put your fuel cap back on, re-connect your battery, and make sure everything is all cleaned up.

10) Time for a test drive!

Just so everyone knows, ALL of the symptoms I listed at the beginning of this post are now gone in my car. No more rough/dying idle, no more sputtering, just a smooth power band, and finally, I drove the car to 15 miles to empty and it was still running fine! I have not run it down to zero yet, but I'm just happy the way it is.

Thanks and good luck everyone.

-Toby.
 
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#43 ·
just got done with this on my aughters 00 323. the retaining ring on the sending unit (drivers) side was a real ***** to get off but otherwise all went well, she was having the 1/4 tank out of gas problem.
 
#47 ·
wow i have all those symptoms except crappy gas milage, im still getting over 27 avg but its got a miss thats occasianal got better when i replaced the ccv and cleaned the mass af meter the miss is still there all though not as often, its got new plugs and the like but what confused me forever was the id be screaming down a clover leaf hit the bottom and try to go and it was out of gas though ive got well over an 1/8th tank left according the the guage. so now i know and to answer the what to do to prevent fire is disconnect the battery and let the computers discharge and by that i mean wait half hour to an hour after disconnect to fully discharge and capacitors in the system same goes for anything to do with the air bags
 
#48 ·
After driving on empty in the boonies searching for a gas station, my fuel pump died the following morning. Searching around e46fanatics and found what I thought was the problem, fuel pump. Sure enough, after ordering a fuel pump from pelican and installation took 2hrs, my car starts up like new! Thanks for the DIY! :bow:
 
#52 ·
Hello everyone,

I was using this DIY post

http://forum.e46fanatics.com/showthread.php?t=592414

to educate myself and get the right parts for this swap out - I ran out of gas twice and have been getting shitty fuel economy. So I ordered the three parts as noted in the above-mentioned post (and a few other similar DIYs):

Fuel Filter. Part # 13 32 1 740 985 KAYSER
Fuel Tank Sending Unit Left Side. Part # 16 11 6 768 788
Fuel Tank Suction Device Right with Main Fuel Pump and Level Sensor. Part# : 16 14 6 766 942

while still at the office.

To my horror, I get to the car and pull out the rear seat and I see 2 wires on the right side of the tank, and NO wires on the left side of the tank. See the attached picture -- one set of wires is brown, the other is red. I lifted all the rubber covers and am positive that none of the wires are threaded under them to the other side.

All the part numbers, model descriptions (including wagon bodytype), and car year matched up between the forum post and Pelican Parts, so while sitting at the office i ordered them without thinking twice. Both level sensors were designated for wagons too...

I have a 2003 325iT(ouring) wagon...

Any thoughts, past experiences (and hopefully good news) are greatly appreciated.
 

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#53 ·
Agh!!! Just found out the possible cause for the 2-wires in one side, vs one wire on each side of the gas tank! Apparently I have an M56 engine instead of M54. The M56 was made for the stricter air regulations, and only sold in California, Massachusets and Vermont. Only 10,000 made! Ugh. More on the specs here:

http://www.bmw-planet.com/lib/M56sulev.pdf

The main fuel system differences between the M56 and M54 engines are and I quote the wikipedia article:

"The fuel tank, tank filler neck and evaporative canister are made of stainless steel. Both the fuel pump and fuel filter are completely sealed inside the gas tank and require a complete replacement of the gas tank if either the fuel pump or filter go bad. A costly bad design which puts the financial burden solely on the consumer."

http://en.wikipedia.org/wiki/BMW_M56

AGH!! Can't even find the M56 parts online...
 
#54 ·
Great write-up. I had the same symptoms and used this to replace both units a few weeks ago, my machine has been running great ever since. It only took about an hour or so to complete. Thanks for taking the time to put this together.

SoCal325iT
Bummer to hear about your engine/fuel tank configuration. Sounds like the procedure will be a lot more complicated. Good luck.
 
#56 · (Edited)
Great DIY!! Many Thanks! My fuel pump gave out at 141k. Car hiccuped as if it was running out of fuel or fuel starved while driving home one night and just died out soon after (55 miles til empty).. It started up briefly and then died out again without any throttle response. After searching e46fanatics and putting in 2 gallons of gas just to be sure it wasn't out, I decided to replace both senders using this DIY. Had to use a jump and the car had rough idle at first, but after I restarted the car a second time I got a smooth idle. Thanks again.
 
#57 ·
What do you think?

Hey guys,

My only symptoms are a rough idle and some stuttering when I floor it, but other than that I can run the tank to empty and my mpg is about right (25 mixed driving). So should I replace both of these bad boys? Just the sending unit? Or look elsewhere for my rough idle problem? Thanks in advance..
 
#58 ·
quick question as im going to do this to my compact tommorrow:
would it not be easier to cut the gas pipe at the end of that retainer?or is there not enough lenth of pipe left to conect it to the new sender?
i must say a big thanks for doing this tutorial,its saved me loads of money!!
p.s im only doing the drivers side,any chance of a bit more info on that clip on the inside,the one push tab connector.
cheers
 
#60 ·
yes mate,just grab the seat from the bottom of the part that you sit on,it sticks out a bit,more or less where your knees would be if you were sitting on it,a few good pulls in a upward motion should do it.its just clipped on,no screws or anything .
let me know how you get on.what side are you doing?
 
#63 ·
Thanks for this excellent write up. My 01 325i has been having issues dying at stop lights, dying when I barely give it any throttle to take off to finally last night acting like there was no power when pressing the gas. After pulling off the side of the road, it would then try to start then sputter and die. Towed it home and this AM cleaned the MAF and replaced all the plugs and still no start. I then tapped on the fuel pump and it started!

Time for the replacement now!
 
#65 ·
Check johnnatalie's post above. I believe that is the answer. The fuel sending unit is really a fuel gauge to tell you when the fuel is low. I'm not sure why there are two of them (one on each side). If you buy a new fuel pump, it should have integrated into it a "fuel sending unit". Someone correct me if I'm wrong (which happens frequently).

I just replaced my fuel pump last night. Thanks to this write-up, it was honestly a 20-30 minute job. Here is my only bit of advice. When I disconnected the fuel line from the pump, it had some built up pressure and sprayed a bit on my back seat. There wasn't a lot of fuel, but the pressure made it spray everywhere. Sprayed worse when I tried to put my thumb on it. I would recommend wrapping the connection in a rag so that when you disconnect the fuel line, it sprays into the rag.
 
#68 ·
great write up. I used your DIY to change out my fuel pump today. the only bad thing I did wa I resused the hose clamp and pump gasket. I ordered the gasket and hose clamp but it did not arrive yet (different shipment from my fuel pump) Drove around the for 100 miles without the rear seats and the metal plates (w/ 10mm bolts) and did not see or smell any fuel leaks so I guess I am good to go.
 
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