Fuel sending unit

[wazzabie]

K5 78 - what are the steps to check if my fuel sending unit. It never worked and I would like to fix it.

what are the ohms range for the unit?

Can the filter at the bottom be replaced?

 

[dyeager535]

I believe all the gauges respond to 0-90 ohms.

See if you can't find some links from me about fuel tank sending unit service manual testing photos. I unfortunately don't have enough time to check my webshots to see if I uploaded any.

 

[bigbadchev84]

try this:

http://www.6066gmcguy.org/Electrical-02.htm

 

[4X4HIGH]

Almost all GM sending units are 0-90 OHMs. Some of the early stuff from the 60's was different but all of our rigs are 0-90 OHMs.

 

[wazzabie]

Thx for the help.

Anyone know if the filter at the end of the pick-up can be replaced?

 

[dyeager535]

Yes

 

[wazzabie]

Yes

This is called the sock. I'm not understanding how it comes off. Maybe it might be better to just run an inline fuel filter outside the tank.

I also mesured the ohms. It starts at 20 and goes to 120. The fuel gauge would always read full untill the last 1/4 of a tank and then it would start to go down fast. It still gave me enough time to know that I needed gas but I never trusted if I had a full tank or note. I would know when I was down to a 1/4 tank.

At empty it is still putting out 20ohms so some problem with it.

 

[4X4HIGH]

They usually just pull off.

 

[dyeager535]

A) there is a repair procedure for the sender. I posted about it, but somoene else posted the entire procedure. It's been awhile.

B) the sock is a push fit over a metal ring on the bottom of the sender. It is designed as a pre-filter, not as a one filter does it all deal. It also is designed to keep water thats in the tank from getting to the engine. (as an update, as I knew I made this comment before but didn't cite my reference and just ran across it, the 1991 R/V manual states "The filter prevents dirt from entering the fuel line and, also stops water, unless the filter becomes completely submerged in water". Page 4-7.