Sending Unit,

Roberto ... here are the pictures ..... a quick reply would be awesome

Originally Posted by David Arabiat

the guide wire isn't tight at all ....
the two filament wires look tight ..this is the picture from that site ....
if i have the time and strength , i will disassemble mine and take a picture ...

i have disassembled it like 5 times aready ... getting tired of it :-P

The guide wire can be easily tightened. Just create a crink in it at the very top or the very bottom using a pair of long nosed pliers.

You said earlier that you are getting false readings from the sending unit, thus indicating that something's wrong with the filament wires. Well you can test it right there by hooking up your fuel pump's connector to the top of the open sending unit and key2ing the ignition (key0, key1, key2, and key3=ignition). The fuel gauge will activate and move up and down according to the position of the fuel float as you move it up and down. You can use visual estimations, it should suffice. You can also use the multimeter to see if the resistances are correct between full and zero as stated in the bentley manual.

If all of this sounds like too much work and you don't feel compelled to do it, just purchase a new unit. Time is money and your car has been down for too long.

Originally Posted by robertobaggio20

The guide wire can be easily tightened. Just create a crink in it at the very top or the very bottom using a pair of long nosed pliers.

You said earlier that you are getting false readings from the sending unit, thus indicating that something's wrong with the filament wires. Well you can test it right there by hooking up your fuel pump's connector to the top of the open sending unit and key2ing the ignition (key0, key1, key2, and key3=ignition). The fuel gauge will activate and move up and down according to the position of the fuel float as you move it up and down. You can use visual estimations, it should suffice. You can also use the multimeter to see if the resistances are correct between full and zero as stated in the bentley manual.

If all of this sounds like too much work and you don't feel compelled to do it, just purchase a new unit. Time is money and your car has been down for too long.

looking at the pictures... can u tell anything concerning my sending unit ?
my car is working .. i have a spare sending unit ... which is even less accurate than my original one ... this one is showing that the tank is completely empty .. below the R letter... which is not true .. coz i filled in 30 liters of fuel yesterday

Hi David,

Just caught your pictures. You posted it at just about the same time I posted my earlier message.

I can't really spot anything obviously wrong with it from the pictures alone. As mentioned, the thick guide wire can be tightened easily by introducing a crick with a long nosed plier which consumes the slack. Just make sure that it stays straight and does not force itself against the float.

You might want to test resistances between the wire from within the wire itself, and from the float's connectors on top of the float, for the same float's position. The problem may be the connector. If it is, there is probably nothing you can do except try to clean the connector and retest, which is something I'm sure you've already done.

A used sending unit is cheap so I would really advise that you spend no more than another 15 minutes on what you've got there to test resistances and the like, or test gauge positions on the car by connecting it to the fp's connector directly, if you don't have a multimeter. If you can't sort it out within that 15 minutes, dump it and get a used one.

Good luck.

If you have an electrician where you live, an ordinary shop electrician not necessarily a car guy, and they should be dirt cheap in Jordan, one of those guys in a hole-in-the-wall setup in the marketplace, you don't need anyone more sophisticated for this, you can take it to them and ask them to resolder joints or whatever they feel needs to be done and tell them what the resistances should be for various positions and they should be able to sort it out for you. Sometimes its worthless cracking our own head over this when labour is cheap relative to the price of a new or used unit.

Originally Posted by robertobaggio20

Hi David,

Just caught your pictures. You posted it at just about the same time I posted my earlier message.

I can't really spot anything obviously wrong with it from the pictures alone. As mentioned, the thick guide wire can be tightened easily by introducing a crick with a long nosed plier which consumes the slack. Just make sure that it stays straight and does not force itself against the float.

You might want to test resistances between the wire from within the wire itself, and from the float's connectors on top of the float, for the same float's position. The problem may be the connector. If it is, there is probably nothing you can do except try to clean the connector and retest, which is something I'm sure you've already done.

A used sending unit is cheap so I would really advise that you spend no more than another 15 minutes on what you've got there to test resistances and the like, or test gauge positions on the car by connecting it to the fp's connector directly, if you don't have a multimeter. If you can't sort it out within that 15 minutes, dump it and get a used one.

Good luck.

the thing is ... my type of sending unit is VERY hard to find .. as u've noticed from the picture .. its comes with a metal top .. with 8 screws in it .... it was used in the E32 and early E34 (1988,1989 ) .. so i did get a used one ... and its installed in the car as we speak .. but the accuracy sucks ...

do u think cleaning the filaments with carb cleaner would make things maybe a bit better ?

about the guiding wire .. im afraid to snap it if i try to tighten it ... does it have any use as far as u know ? the float doesnt seem connected to it in any way ...

sorry for bothering u with my sending unit problems

Originally Posted by robertobaggio20

If you have an electrician where you live, an ordinary shop electrician not necessarily a car guy, and they should be dirt cheap in Jordan, one of those guys in a hole-in-the-wall setup in the marketplace, you don't need anyone more sophisticated for this, you can take it to them and ask them to resolder joints or whatever they feel needs to be done and tell them what the resistances should be for various positions and they should be able to sort it out for you. Sometimes its worthless cracking our own head over this when labour is cheap relative to the price of a new or used unit.

i think an electrician can easily resolder the guiding wire for me ....
but the resistances ... how do i know what the resistance should be like in various positions ?

Please check the relevant section in the bentley manual. Please search for the searchable download on these forums.

Originally Posted by robertobaggio20

Please check the relevant section in the bentley manual. Please search for the searchable download on these forums.

yeah i saw how to check the resistance ... gonna go buy an ohmmeter today and try the resistance on it

Originally Posted by David Arabiat

yeah i saw how to check the resistance ... gonna go buy an ohmmeter today and try the resistance on it

Get a digital multimeter dude....$5 shipped from ebay if you are stateside. Its basically sold for peanuts worldwide from what I hear.

Originally Posted by robertobaggio20

Get a digital multimeter dude....$5 shipped from ebay if you are stateside. Its basically sold for peanuts worldwide from what I hear.

well ... my resistance readings are as following :

G and 31 on empty = 91.5 ( chart says normal is 88.7 +-2.8)
G and 31 on full = 4.4 ( chart 3.2 +-0.7 )


i dont know what that should tell me :-P
any idea ?

That tells you that your fuel level sender is working perfectly. Something else is wrong with it.

Or maybe its perfectly fine. Its quite possible that its your wiring that is screwed. I have a friend, a forum member here, who's fuel level sender also gave bad readings. Please do a search for mamij. Nevermind, I found it :

http://www.bimmerfest.com/forums/sho...d.php?t=521531

http://www.bimmerfest.com/forums/sho...d.php?t=483780

The fuel level sender (fls) was fine. The problem was traced to wiring insulation in the fls's circuit that had been chafed off and was causing a mild short and thus screwed readings. Please pm him directly for more information on how we solved the problem. cheers.


Roberto

hi again... so im still having problems with my sending unit ... it acts crazy .... i noticed this ... when i steer left... the sending units seems to float ... when i steer right .. the arrow goes down about 20 liters or more .... can the problem be not the floater or the filaments , but rather the plastic cylinder cover ?
i removed that cover from an old sending unit .. and tested it in water ... found out it has alot of places where it leaks air (and water ) ... should the plastic cover be completely sealed ?
i tried using the a tape to close the leaks ...
so my question is , does it matter whether it leaks water from the side or not ? coz im thinking since im turning right all fuel from the cylinder seems to leak out ... thats why the guage drops ...

here is what i tried to do ... didnt try it in the car yet ... stupid idea ? anyone ?

Bad idea very bad idea ( with the tape ) that's normal when u turn left my gage also goes up and turn right it goes down . Granted yours is a little off , but mine does the same you figure on a 22 gallon tank 5plus gallons is about on empty and 2 gallons of the 5 is the reserve . So in retrospect 3 gallons is what should only register on the needle and the 2 gallons is for the solid low fuel light ( reserve is 2 gallons )

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but it wasn't like that a couple of years ago ... the needle would never move up or down no matter how u turn ....
its annoying when you put in 5-6 gallons of fuel and then make a hard turn right or go uphill , and u see the fuel light turn on !! makes you doubt yourself ... then you drive downhill .. and the needle goes back to 30 liters !

LOL I know but these are old cars . And tape will only add problems . Google how much a new sending unit is and you can make a monetary decision if its worth replacing it or learning to live with the slight annoyance . You've been doing it for a couple of years now

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Originally Posted by supertech777

LOL I know but these are old cars . And tape will only add problems . Google how much a new sending unit is and you can make a monetary decision if its worth replacing it or learning to live with the slight annoyance . You've been doing it for a couple of years now

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true .. true :-P
but then again .. what should i believe ? the needle when it shows less fuel .. or the needle when i shows more fuel ?

Originally Posted by David Arabiat

true .. true :-P
but then again .. what should i believe ? the needle when it shows less fuel .. or the needle when i shows more fuel ?

Do you think that it is accurate when it is on level ground and you are not turning? I would think that might give youi the most reliable reading.

Originally Posted by BMR_LVR

Do you think that it is accurate when it is on level ground and you are not turning? I would think that might give youi the most reliable reading.

+1

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the gauge in my swapped E34 sometimes plays up too. i never use it though, my very first BMW E30 had a screwed sender, i learnt that once i had done around 400km it was time to fill up again, and have used that theory on all my cars since. My econovan is 300km and my E34 is 350miles or 500km depending on which E34 im in.

of course, this wont work if you only put $30 or so in at a time, you have to fill to the top each time.

A loose guide wire may be jamming the float and stop it moving smoothly/at all.

Error - sorry folks - can be removed.

Originally Posted by _Ethrty-Andy_

the gauge in my swapped E34 sometimes plays up too. i never use it though, my very first BMW E30 had a screwed sender, i learnt that once i had done around 400km it was time to fill up again, and have used that theory on all my cars since. My econovan is 300km and my E34 is 350miles or 500km depending on which E34 im in.

of course, this wont work if you only put $30 or so in at a time, you have to fill to the top each time.

hmm .. thats exactly what i do .. fill it up with 30$ of fuel every time ... 28 dollars to be precise the 28 dollars get me 25 liters of fuel ... the 25 liters of fuel get me 200km .. thats when go for refueling ... so 25 liters give me 200km of driving ... i know it might go more .. but because of the inaccurate fuel guage , i just decide to refuel ...