Dsmauney

Hey guys! I have installed 2 new Zo6 fuel pumps with fuel level sensors, both pumps will only show half a tank of fuel when the car is completely full. After driving the car around a 100 miles the gauge goes to completely empty then after you shut the car off and turn it back on the CEL for fuel level sensor comes on... I thought to begin with I had a faulty pump but both brand new pumps have done the same exact thing, then I thought maybe the zo6 fuel level sensor wouldn't work for the base but part numbers are the same.. Any help is greatly appreciated!!!!!!

schpenxel

What part number pump are you using? Where did you get them?

I just had the exact same thing happen on mine. 2005 as well, Z06 pump.

Basically the driver side fuel level sensor isn't being picked up (for whatever reason), and the computer realizes the passenger tank can't be full and the driver tank empty without there being something wrong. So, thus the error.

I assumed (perhaps wrongly) that the sensor arm was caught on a hose or something inside the tank, but I wonder if it's possible something else is going on

I wanted to compare the part you got vs. the one I got to see if we have the same part or not since mine is an 05 as well

I was going to read the resistance between the wires that are for the fuel level sensor this weekend and see what they read. I think I still have my original stock one around here somewhere so I can compare it to that too

Very strange that we are having the exact same problem.

Dsmauney

The part # I used both times is MU1889 acdelco#19207959!!

I have done a little research on part numbers this morning and its looking like 2005 used a different part number for the fuel level sensor than the other years, looks like 2006 up base and c6zo6 fuel level sensors are the same so I must have been mistaken in my original post..

schpenxel

That is very strange.. I'll do some more research on the fuel sender part numbers. That would certainly explain why we both are having this problem, if the 2005's do indeed use a different one. Seems someone else would have figured that out before us though.

The '05 is a weird year, but I didn't expect to find any difference between the fuel senders

This is the one I purchased:

I still have my stock one laying around here somewhere.. and I have another one of the one I just posted a link to.. so I am going to try to compare how the level sensors behave with a multimeter and see if they are the same or not.

schpenxel

I checked the part number on gmpartsdirect.com for a 2005 base, 2006 base and 2006 Z06 and all should 88967316 as the part number for the driver side fuel level sensor, so I don't think that's the problem

Dsmauney

Hey buddy just wanted to give you a heads up, I put the 2005 fuel level sensor in the car BACK TO NORMAL !!!! I kept the Zo6 pump and put the 2005 fuel level sensor on that pump!!!

Dsmauney

BTW that is the right part number for the fuel level sensor but its a different part # for 07+ so I believe we must both have 07 + fuel pumps..

schpenxel

Thanks for letting me know!

I think you're right.. mine is working almost backwards. When I get down to almost no fuel on both tanks the fuel gauge starts going up. It got up to 1/4 tank when I had used about 15 of 18 gallons.

When I was filling up at first the fuel gauge went down.. then once the driver tank was full and the passenger tank started filling, the fuel gauge started going back up. It got up to 1/2 tank on the gauge, as expected..

I'll ohm out the old fuel level sensor I have laying around and the new one. That way I can confirm it and hopefully save some other people some trouble in the future!

You're right though.. I bought a Z06 pump + sensor.. so I assume it's for an 07+

Did you just pull the tank out the bottom with the drivetrain and all still installed? I dread doing that. Last time I pulled mine out I had the drivetrain out so it was easy.

schpenxel

Figured it out!

They work opposite.

Here's the fuel sensor level vs. fuel remaining table for a 2005


and for a 2007:



They work opposite!

schpenxel

Updated tune and voila! Fixed! Woohoo!

BLOWNBLUEZ06@RKT Performance

Great discovery!

A hellluva lot better than pulling the tank and swapping the sending unit!

schpenxel

Indeed! This is something I've never seen mentioned on the forum. I think most swap the pump but use the original fuel level sensor.. so that's probably why.

I'm just glad I didn't have to pull the damn tanks. Everything else was working properly with the crossover, etc., so I really didn't wan to risk messing something else up in the process.

I need to make some small changes still--when 100% full it reads slightly less than about 7/8 full on the gauge. Not a huge deal, I'll probably try to fix that at some point though.