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Chrisoswald
06-11-2012, 03:37 PM
88 prostar...pics ar of my current sending unit. not sending! when i ground the connections fuel gauge reads full. I tested the continuity of this sending unit with my meter and only get continuity when the float is in the FULL position so i am assuming that the sending unit is toast as i should have continuity throughout the full range of motion of the float....correct?

thatsmrmastercraft
06-11-2012, 04:32 PM
You are correct, sir.

ricford
06-11-2012, 04:38 PM
Maybe just semantics, but continuity implies 0 ohms. You should only have 0 ohms when full. Not sure what the value should be when empty, but it would vary throughout the range of motion. If you are using a continuity tester it will only show continuity at full. An ohmmeter should show the variation.

Chrisoswald
06-11-2012, 04:38 PM
any special brand to use (or avoid) on the replacement..the one i pulled out was teleflex...i also found a moeller that would work...with price matching at west marine i can get either for under 25 bucks..any opinion on brands?? thanks!!

mikeg205
06-11-2012, 04:50 PM
you need to connect up a resistance test....240-30 ohms....

check senders here... www.wmausa.com

Chrisoswald
06-11-2012, 04:51 PM
Maybe just semantics, but continuity implies 0 ohms. You should only have 0 ohms when full. Not sure what the value should be when empty, but it would vary throughout the range of motion. If you are using a continuity tester it will only show continuity at full. An ohmmeter should show the variation.

so let me understand...when using my meter with the sending unit out of the boat (no power to the unit) i will only get an audible tone when full? i hope i am explaining this correctly but when i am testing for what i call continuity (ie my meter gives a tone) i only get tone with the float in the full position..as i simulate the float falling to empty...no tone. I assumed that you would get continuity thru the entire float range of motion..so if continuity is only at FULL i need to supply 12V to the unit, set my meter to ohms and test to see if i am getting fluctuation in ohms throughout the floats range of motion? correct?

thatsmrmastercraft
06-11-2012, 04:53 PM
so let me understand...when using my meter with the sending unit out of the boat (no power to the unit) i will only get an audible tone when full? i hope i am explaining this correctly but when i am testing for what i call continuity (ie my meter gives a tone) i only get tone with the float in the full position..as i simulate the float falling to empty...no tone. I assumed that you would get continuity thru the entire float range of motion..so if continuity is only at FULL i need to supply 12V to the unit, set my meter to ohms and test to see if i am getting fluctuation in ohms throughout the floats range of motion? correct?

This is the correct test for the sending unit.

Chrisoswald
06-11-2012, 04:58 PM
thanks guys...am i safe to assume that if my fuel gauge on the dash always reads empty and if i touch the pos and neg lead at the tank together and the gauge on the dash pegs to past full my dash gauge is functioning correctly? I read at some point that is a correct assumption. I will test the sending unit to confirm its a goner (which i think is the case) but just want to be certain that i am correct in that the dash gauge is OK...thanks again!!

mikeg205
06-11-2012, 05:03 PM
put ohmmeter on sender - move float... if you get a resistance change - sender ok... if sender ok...reconnect send to gauge...move float... if gauge needle does not move with float movement gauge is no good.

Chrisoswald
06-11-2012, 05:25 PM
thanks...i think i was making this harder than i needed to!!! when hooked up to my ohmmeter i get nada..nothing at all...i assume no reading is a dead sender

mikeg205
06-11-2012, 05:34 PM
thanks...i think i was making this harder than i needed to!!! when hooked up to my ohmmeter i get nada..nothing at all...i assume no reading is a dead sender

no reading - no resistance... short circuit...

mikeg205
06-11-2012, 05:41 PM
24 years old....dang...nothing lasts anymore... :D

sorry couldn't resist... if you replace I suggest a mechanical...I bought a resistance tube type...lasted 2 seasons... so I went with a float type from company mentioned above...

thatsmrmastercraft
06-12-2012, 01:09 AM
no reading - no resistance... short circuit...

Or open circuit. I guess it depends upon how you read "no reading". Either way it's time for a new sending unit.