Fuel Sending Woes And Headaches

Hi all! I've reached the end of my rope and the scope of my knowledge trying to get my fuel gauge to work and I could use a fresh set of ideas. A little backstory for ya: In January the stock fuel pump in my '99 finally died. I was in a bit of a financial pinch so I picked up a delphi pump and carefully put it in, and put everything back together. All was well for about 3 weeks. I stopped in a shell station to get gas, and put about half a tank in to bring it up to 3/4. Drove about 10 miles down the road and my fuel gauge dropped out to below empty and my low fuel light came on. It jumped back to where it was supposed to be 30 seconds and later and went back and forth for about 2 minutes before it just fell down to E with the light on again and was stuck that way for a while.

Fast forward about 2 months later when I have the free time to work on it. I run diagnostics on the car which returns dtc9202 and Fuel 255. I'm aware this is a fairly common problem, so I get my pump traded out under warranty and spend all day yesterday dropping my fuel tank and swapping out the pump. I crank it last night, and get literally 2 miles down the road and the gauge drops out again with the low fuel light on. As you can imagine, I was pretty sad.

I've heard stories of people replacing sending units and pumps only to discover it was something called an anti-slosh module. Any ideas at all would be greatly appreciated! If it helps any, my baby is the 1999 3.8L V6 35th Anniversary model

p.s. If anyone helps me get this SOB fixed, and you're ever around the Memphis, TN area, I'll definitely buy you a beer!

Az Pete said:

Did you verify the sending unit on the remove pumps was in fact bad? Had a Focus that acted up and after the pump was replaced, I located a loose connection in the gauge wiring.

Most info I found searching the Web related to 93 and older on the anti slosh module. If the car has one, it is most likely behind the gauge cluster and wired in line with the gauge. Cleaning the contacts seemed to help many I read.....but again, on the older Mustangs.

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You know, that might just be the problem. My friend recommended checking the harness that starts on the fuel tank. I feel like he's right because my gauge worked until I hit a good bump and then bam. Game over. I'm just hoping it's loose somewhere towards the front of the car. It's way too damn hot to be dropping the fuel tank over and over again.

Although, it makes me curious. The code it threw up was an open sending circuit. If something had gotten disconnected wouldn't there be an overall bigger problem? Or does the fuel pump and sending unit operate off of their own separate connections? Pardon the ignorance. I'm handy with all things mechanical on my car. I don't prod around the electronics too often.

Mattstang04 said:

I wonder if you got a chafed wire that's grounding and shorting the gauge out. Kinda sounds like it's cool until it suddenly grounds. Hit a bump, and it knocks it out.

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I feel like that is the problem. The only issue I have now is finding the bastard. Ive followed both of the wiring harnesses all the way up to this metal box thing on the driver side in the trunk. Not exactly sure what that does. Hmm.

Update: I dropped the tank again and checked all the wires all the way up until they go into the body of the car. The connectors were all in good shape. I sprayed contact cleaner on them and sealed them with dielectric grease. Fired up the car and all was well until exactly 1 mile down the road. My odometer stopped working followed by the fuel gauge yet again 2 seconds later. The Odo eventually came back, but the fuel gauge not so much. Im starting to think it may be a bad connection somewhere towards the front of the car. However,I have NO idea where to start looking.

Az Pete said:

Not sure how the wiring attaches to the instrument cluster but I would consider pulling it to check all the conections. Also, try letting the car idle in the drive for the time it takes to drive that mile....that might clue you if it is movement or current overload that causes it to fail.

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I may do that next. I got yet another new sending unit. It's slightly different from another one. It passed all the electrical testing. However, if it works with this new unit I'll let it idle for a bit.

If anyone can tell me the significance of this connector running into the evap lines I would surely appreciate it. Im not sure if it has anything to do with my problem, but it's always nice to know.