Correctly adjusted fuel gauge sender, empty tank resistance reading Once you've fiddled your brains out and get close as you can you can, then get some fixed resistors in the values given above (20 and 222 Ohms, or use a single variable 1K ohm potentiometer and use your multimeter to calibrate it before attachment). 0000010103 00000 n That would actually be a very useful piece of information - what do the white lines correspond to in terms of ohms. Powered by Invision Community. �ĩ�S��[�-q&����g��̥p�|>2��O�gaj8�ҏ�~t"�0K]�u�Nx�,u5��ZX3����ײ45xhmn!���h}Y���c�~�@Y��_ ��� I'm sure someone on here knows what the min and max resistance is supposed to be. Procedure. 0000022255 00000 n Paste as plain text instead, × You do not need to drop your fuel tank to change or customize your sender or re-calibrate your fuel gauge. �CE���B�h+q؇�� 41�Q��~6�:i�H~�v����X�n��=�� ��ـ�p��Ω8ۙ�~[v�7^E�\��}��A�9D��0�ӳ.�R�[�:w����^AT߼���( Cavitating pump = loud pump. Testing can be done by removing the sending wire from the gas tank sending unit and plugging in the test unit. You can clean them gently with solvent / lubricant. 0000003510 00000 n I re-assembled and it still gives a lopsided reading. 0000001725 00000 n It is ready about twice the fuel it should, so I put together a voltage divider using a dual cement 5 watt resistor. You may use 18g or 20g stranded wire for all fuel level gauge wiring. deschodt, October 23, 2017 in BMW 2002 and other '02. This will "polish" the wire and remove any debris that could cause the float to stick. It's linear, so at midpoint the reading should be 37.5 ohms, etc. The only easy way to accomplish this is to reduce the voltage to the fuel gauge with a small voltage reducer (resistor!). 0000076586 00000 n Make sure the brown ground wire on the sender is clean and making a good ground (in addition to checking the ground on the instrument pod). Make sure the brown ground wire on the sender is clean and making a good ground (in addition to checking the ground on the instrument pod). If you have an account, sign in now to post with your account. The fuel gauge is composed of two components: a sender in the tank and a gauge on the instrument panel. × Try rotating your sender several times to get the float to slide from empty to full. I build a cheap testing device using a 0 to 100 ohm potentiometer, then built a small box to house it and marked the exact calibrations for 0, 33 and 78 ohms on the box. EIS Model 4000/6000/9000 units have 6 user-definable Aux inputs. When I tested the sender I get about 12 ohms when the float would be at its highest in the tank and 311 at the lowest. 20 AWG is sufficient for most wiring. They can be cleaned (VERY carefully) with carburetor cleaner and a Q tip. FWIW - the increments on a 2002 fuel gauge are not linear. �x ����BE�_�^��]/����Q���I��%���s�PڠMu8:T�. Zero ohms correlates to "empty" and 90 ohms correlates to "full". I disassembled mine and it was relatively clean. Today I decided to take a closer look and pulled the inline Mann fuel filter, which immediately shot fuel 6ft in the air (pressurized). The fuel gauge is composed of two components: a sender in the tank and a gauge on the instrument panel. I think I have a compatibility issue. Thanks for the synopsis guys. I've seen it happen. They say "Connect to 12 Volt directly. Wiring suggestions ? h�b```a``�����p�,?�3�EY8ZV�10Lq`@��*�^:����B��`)��������@Z���"��L}lW��'0=c�g��x�u {�…8�y�NMq,g��,��~u��3�Z ���LؓW;�2 -`���@�+�Al��d�4;��@����A���p00 �@D ��+� As built in Cirrus Perspective since years they might have an excellent reputation concerning accuracy of fuel level indication. 0000056701 00000 n Those hair-thin resistance wires that the float contacts get coated with crud and varnish--especially on a car that sat for some time with little fuel in the tank. The sender consists of a float on an arm that varies the resistance the sender applies to the circuit with gauge. If it's a brand new sending unit (or one installed previously by someone else, recently), someone may have neglected to remove the set pin / thin wire that holds the float stationary during shipping. Can you calibrate the fuel gauge ? 0000007190 00000 n 0000003462 00000 n If it's true I'm not going to mess with my sender anymore. endstream endobj 65 0 obj <> endobj 66 0 obj <>stream I'm going in again. Out of Calibration Reason 1 The resistance range of the sender unit is wider than what gauge can indicate. Are you saying that all new 02s out of the showroom were like this? When the tank is empty the float sits on the bottom of the tank. To convert a resistance sensor to a voltage, a pull up resistor is required, see figure 1 below The resistor shown here has an actual value of 135 Ohms and as can be seen, this causes the sending unit to appear to have an EMPTY value of near 90 Ohms. The gauge does not appear to coincide with the sending unit. I'm not cancelling the order, just because California pissed me off... good to have a spare before they start scanning packages too. 0000061228 00000 n SENDING UNIT The sending unit is installed in the fuel tank and consists of a float and arm that is attached to variable resistor. There you go, problem solved ! Level sensor is actually an FD's which is 10-70 ohm I believe I'm using a 33 ohm resistor. Consulting my good ole BMWnospaceCCA Tech Tips book from 1975, the writeup on the 2002 fuel sender shows that with the float at the top of its travel (full tank) an ohmeter placed across the two contacts should read essentially zero ohms, and with the float at the bottom of its travel (empty tank) the ohmeter should read 75 ohms. ‪Fuel gauge calibration‬‏ - YouTube ... but I can tell you that using a variable resistor or potentiometer is the method for testing gauges and gauge circuits in Ford dealerships for most cars made basically forever up until recently when gauge circuits are becoming digitized. I always assumed fuel tank sender units worked thus: + -> potentiometer (in the fuel tank) -> output -> fuel gauge -> gnd -> gnd So I had it all working great on the bench using the output from a potentiometer to read the voltage into an analog pin on the Arduino. 0000056548 00000 n 0000060903 00000 n Perhaps it's sticking part way and not dropping as the fuel level falls away beneath it. When I tested the sender I get about 12 ohms when the float would be at its highest in the tank and 311 at the lowest. Display as a link instead, × 0000000016 00000 n   Pasted as rich text. A 40 Ohm resistor will indicate about 1/2, and a 60 Ohm about 1/4, etc. The 3/4 mark is near the full mark and the 1/4 mark is near the empty mark... so the first 1/4 seems like it lasts forever and the second half of the tank seems like it disappears quickly. When new, the range of the resistive signal is between 0-90 ohms. GM cars from the 1930s to the 1960s operate on a 30 ohm scale. When the tank is full, the resistance to the fuel gauge is about 4 Ohms. I'd start by seeing what the resistance swing is as you make the sender go through full travel. 0000009260 00000 n 0000001116 00000 n %%EOF to the fuel sending unit to alter its resistance range to match the aftermarket gauge. h�bb�e`b``l � + � 0000002077 00000 n Such a pull up resistor is not available on the market so choose a 1200 Ohm 1/4W resistor (very prudential power value) with a 5% precision. The arm moves the wiper on the variable resistor to zero ohms or a short circuit. GND = Connect this to engine or chassis ground. (Right tail light assembly shares a common ground with the fuel sender). Can I put my gauge cluster into DEMO mode, for display at an event, or testing purposes? 0000008491 00000 n That way, you will be able to vary the resistance in multiples of 10 ohms and see if the gauge behaves linearly or not. I digress, I'm a genius (not). endstream endobj 94 0 obj <>/Filter/FlateDecode/Index[17 38]/Length 20/Size 55/Type/XRef/W[1 1 1]>>stream Yep. Don't know if this is your problem, but I thought I'd share the thought. Some tests can be done to get an idea of the accuracy of the gauge. GM cars from the … Fuel senders have a rheostat that provides a resistance to ground. 0000009130 00000 n EMPTY. I was going to clean my wires, but no longer. Also connect one of the resistors to ground on the case, and you can leave it connected that way for the duration of this calibration exercise. I get 100 miles in the first 1/4 tank. To correct for this variability, in gasoline applications we use a scheme we call Full Detection where the sender detects a fillup and rescales the calibration if the reading would otherwise be something other than Full due to the percentage ethanol.   You cannot paste images directly. Shown between the two test leads is the additional resistor parallel to the sending unit.