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Fuel Pump Help

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Old 03-24-2018, 10:29 AM
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Attached are some pics of what I did for the trap door on my car along with some pics of my modified fuel pump assembly. I've since went to a different pump but the small purple wires are the ones connected to the fuel level sensor that attaches to the bucket and to the supplied connector from the racetronix hotwire kit.
Attached Thumbnails Fuel Pump Help-20180204_103906.jpg   Fuel Pump Help-20180204_103937.jpg   Fuel Pump Help-20180204_171251.jpg   Fuel Pump Help-20180204_172417.jpg   Fuel Pump Help-20180324_100906.jpg  

Fuel Pump Help-20180324_100910.jpg   Fuel Pump Help-20180324_101016.jpg  
Old 03-25-2018, 07:59 PM
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I have issues with my sensor too. I think the sensor itself was just worn and the simple act of taking the assembly out was enough to throw it out of whack. I tested it with the assembly out of the tank and I noticed if I was letting pressure on the sensor contacts I would get a reading on my gauge. With it in the tank I just think the leads are just worn enough to be slightly loose because I get intermittent readings. Sometimes it works sometimes it doesn't.

​​ if anyone has a part number for the sensor itself that would really help. I don't want to buy a whole bucket assembly just for the sensor.
Old 03-25-2018, 08:54 PM
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The last photo in the post by 01CamaroSSTx above shows where the fuel gauge gets it's signal. Those purple wires go to a reostat-type sensor. Your friend/mechanic probably didn't connect those wires to the fuel pump module when he changed the pump.

The new pump comes with a plug, which has two wires in it already. You have to "move" the purple wires from the old pump's plug to the new pump's plug. If you don't do that, your fuel gauge won't work. If you cut the purple wires, or screw-up the pins on the end of the wires (like I did), then you're screwed. You will probably have to buy a new module, unless you can find new pins for the purple wires/connector.
Old 03-26-2018, 03:49 PM
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Originally Posted by jaxcam02
You'll also want to replace the fuel pressure regulator, that's what is causing your priming issues. Ac delco #217-1598
Priming issues come from the check valve in the pump itself, not the pressure regulator. The pressure regulator bleeds off pressure above a set pressure, it doesn't allow to fuel to bleed off below that pressure, that's what the check valve's job is. I've replaced 100's of pumps for this in my time as a tech.

There is a check valve in the fuel pump that keeps fuel in the line so that the system primes quickly as soon as the pump comes on. When the check valve goes bad the fuel drains back into the tank and the pump has to fill the line then pressurize it which takes a few turns of the key, a few primes. If it were the pressure regulator causing it it would never build up.
Old 04-06-2018, 12:48 PM
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Bought a new fuel level sensor unit for only $10. Search ebay for "MU172"





Works great.
Old 04-06-2018, 01:20 PM
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Thank you for all the help guys. The fuel level sensor kicked back to life on its own after a week... I filled the tank up and drove it around for a while, and it's behaving like it should. (Gauge went to full on fill up, went to about 3/4 tank right around the time it normally does from driving all around town.)
Old 04-06-2018, 02:51 PM
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Originally Posted by SouthernRex
Thank you for all the help guys. The fuel level sensor kicked back to life on its own after a week... I filled the tank up and drove it around for a while, and it's behaving like it should. (Gauge went to full on fill up, went to about 3/4 tank right around the time it normally does from driving all around town.)

Glad to hear it!




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