My fuel gauge is not accurate as I once ran out of gas when the aftermarket gauge showed 1/2 tank. I don't know if the sending unit is bad or the gauge is the problem. Question is, How do I access the fuel sending unit and how can I test it?
Fuel Sending Unit 78 Malibu
- Thread starter Malibu Frank
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First have fun getting a new one, been waiting months for mine on backorder.
Check the ground wire first it comes from the top of the tank and grounds on the back of the body or frame. Mine was pretty rusty and loose. Fixing it didn't help in my case.
The sending unit is in the gas tank. The resistance is 0 (empty) to 90 (full) ohms.
I think the wire from the sending unit is pink, at the gauge ground the terminal with the pink wire and it should read empty ( it has to have power to the gauge so key on). If you can get a 91 ohm resistor (white, brown, black stripes) put it between the pink wire terminal and ground and the gauge should read full (you need to remove the pink wire to use the resistor accurately).
Check the ground wire first it comes from the top of the tank and grounds on the back of the body or frame. Mine was pretty rusty and loose. Fixing it didn't help in my case.
The sending unit is in the gas tank. The resistance is 0 (empty) to 90 (full) ohms.
I think the wire from the sending unit is pink, at the gauge ground the terminal with the pink wire and it should read empty ( it has to have power to the gauge so key on). If you can get a 91 ohm resistor (white, brown, black stripes) put it between the pink wire terminal and ground and the gauge should read full (you need to remove the pink wire to use the resistor accurately).
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I know the sending unit is in the tank, Can i get to it from inside the trunk or does the tank need to be lowered?
There's many ways to do it, but you always end up at the same place. Here's a Monte Carlo tank drop. Extremely similar to a 'bu so you get the idea what you'll need to do. It's not tough, but don't do it with a lot of gas in the tank. You may have 3 or 2 tubes on the sender, but the procedure is the same.
GM p/n for MOST A/G bodies (not wagons) is:
25001612 or equivalent for 2 tube sending unit (Spectra FG08B for 40 and change, or Dorman 692049 on Rockauto for 50 and change)
25001613 or equivalent for 3 tube sending unit. (Dorman 692089 on Rockauto for 48 and change)
Check your own application to be sure which you need.
25001612 or equivalent for 2 tube sending unit (Spectra FG08B for 40 and change, or Dorman 692049 on Rockauto for 50 and change)
25001613 or equivalent for 3 tube sending unit. (Dorman 692089 on Rockauto for 48 and change)
Check your own application to be sure which you need.
Check your wiring inside the trunk on the left hand side. It's aluminum and often breaks. Repair one spot and another breaks. Well known issue.
Correct, and sometimes on the back of the instrument cluster there is erosion and damage.
I had to rewire mine by running over 10 foot wire through the trunk, under the tail light and then to the send unit.
i bought an in tank unit for my 81 malibu several years ago from this forum for a project. paid 20 bucks plus shipping. it's a feed and return line type. sold the car and never used the sending unit. i'll give you the same deal if interested.
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