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agarabaghi
06-08-2011, 03:58 PM
So i took readings from the fuel sender plug the other day.

Black and Red = 10ohm
Black and White = 1.5ohm

This made me think that the tank was 1.5/10 full...

So we put 15 gallons of gas in and took readings again.

Black and Red = 10ohm
Black and White = 1.5ohm

Shouldn't the resistance have gone up as we added almost 1/2 a tank of gas?

Is this telling me the sender is bad?

agarabaghi
06-09-2011, 09:02 AM
no one has a clue?

j.mccreight@hotmail.com
06-09-2011, 09:04 AM
I'll measure a fuel sender when I get to work...

agarabaghi
06-09-2011, 09:08 AM
I'll measure a fuel sender when I get to work...

Thanks!

This is on a 2006 X1, I just put the meter on the plug from the sender unit. Black and Red and then Black and White (middle one).

j.mccreight@hotmail.com
06-09-2011, 10:06 AM
I think your measuring method is wrong, stand by

agarabaghi
06-09-2011, 10:13 AM
lol... how wrong could i be?

Let me know your procedure and i will follow. My sending unit has 3 wires from the plug Red (+) / White (STD) / Black (-)

Red and black = 10ohm on meter
White and Black = 1.5ohm on meter

j.mccreight@hotmail.com
06-09-2011, 10:43 AM
First I'm not a MC mechanic, so I don't know their wiring diagram. (Nissan, GM). There are generally 2 types of senders a 0-90 ohm and 33-240 ohm. A fuel level sender is just a potentiometer. The first number will be empty. If MC uses a GM sender like they use their fuel pumps it will be the 33-240 ohm type. Senders work by sending an analog signal to an ecm, mdc or some kind of control unit this is used to convert an analog signal to a digital signal for the digitally processed gauges, I believe MC uses medallion digital gauges. You really need to remove the assembly for an accurate diagnosis. Ok here it goes. Disconnect the connector you do this so your not getting inaccurate readings and possible burning out the ecm, one lead of dvom to ground wire and the other lead to the other side of the sender, you do not switch the wires of the sender to measure the empty or full readings. like I said I don't have a MC diagram. now measure the ohm value, empty float down should be around 33ohm and full float up will be around 240 ohm half a tank will be around 105ohm give or take a little. If the sender is a 33-240 and your readings are in this range then I would say your sender is good and you need to start looking at other components for the problem, like I said you really need to remove the sender and test it on the bench so you know your on the correct 2 wires and so you can move the float up and down. you can pm me if you need to and well discuss it. Hope this helps, James

agarabaghi
06-09-2011, 10:45 AM
I see... Ill take a look when im back on the boat.

76S&S
06-09-2011, 01:24 PM
No PM's please, inquiring minds want to know!

agarabaghi
06-09-2011, 01:36 PM
I will post here when i get into the boat, wont be till later tonight or tomorrow.

willyt
06-09-2011, 01:57 PM
Indeed - I have a similar problem on my 05 X2

76S&S
06-09-2011, 02:32 PM
thanks........

JimN
06-09-2011, 03:16 PM
So i took readings from the fuel sender plug the other day.

Black and Red = 10ohm
Black and White = 1.5ohm

This made me think that the tank was 1.5/10 full...

So we put 15 gallons of gas in and took readings again.

Black and Red = 10ohm
Black and White = 1.5ohm

Shouldn't the resistance have gone up as we added almost 1/2 a tank of gas?

Is this telling me the sender is bad?

Is your sender the kind that's a skinny aluminum tube with a black top that has two adjustment "screws" or is the aluminum tube about 1-1/4" diameter? Can you post a photo of the sender, out of the tank?

If it's the skinny one, measuring resistance is useless because it doesn't have any moving parts- it has active electronics and it measures capacitance. Also, they're accurate in clean fuel or whatever other liquid they're used in, which is why they have the adjusters.

agarabaghi
06-09-2011, 03:59 PM
No adjusters. It has a 3 wire plug, and maybe 8 screws going into it. Im at work and cant remove it yet.

JimN
06-09-2011, 04:45 PM
No adjusters. It has a 3 wire plug, and maybe 8 screws going into it. Im at work and cant remove it yet.

Your boat had 3 wires going to the original sender? I thought they all had a pink wire and a black wire, with a green ground wire that attached to the aluminum plate in '94. Should have had 5 screws, going into metal inserts in the mounting plate. The forst ones I saw with red/black/white wires was in '99 and that lasted part of one year. Those boats needed an interface module to work correctly with a two-wire sender.

agarabaghi
06-09-2011, 05:01 PM
ill take a pic.

j.mccreight@hotmail.com
06-09-2011, 05:13 PM
Your boat had 3 wires going to the original sender? I thought they all had a pink wire and a black wire, with a green ground wire that attached to the aluminum plate in '94. Should have had 5 screws, going into metal inserts in the mounting plate. The forst ones I saw with red/black/white wires was in '99 and that lasted part of one year. Those boats needed an interface module to work correctly with a two-wire sender.

He now has a 2006 X1 thats has this problem...

agarabaghi
06-09-2011, 05:14 PM
http://img825.imageshack.us/img825/985/imagerka.jpg

http://img196.imageshack.us/img196/3880/imagexlt.jpg

http://img810.imageshack.us/img810/9513/imagenyt.jpg

j.mccreight@hotmail.com
06-09-2011, 05:24 PM
Pull the sender out, unplug the connector use the blk and white wires on your sender to your meter leads move float up and down and record the ohm values, of course if its like the sender jimn is talking about I have no clue on how to test that floatless sender, if it doesn't go to 240 ohm it simply might be a different ohm value sender also watch the readings to check for smooth movement of level and readings...

j.mccreight@hotmail.com
06-10-2011, 05:45 PM
Any new information...