Okay, so I had parked my car for a couple hours the other day, and when I got back in it and fired it up, I pulled a CEL and a DIC message that read "engine power reduced". I called OnStar, had them narrow down the code and it came back as the high flow fuel pump was not getting any voltage. Diagnostic tech recommended I wiggle the wire and see what happens. So I then proceed to fiddle with the Fuel Pump sensor wire. I notice from when the gm tech replaced my cam shaft sensor, they "broke" the wire harness that straps into the black bracket beside the fuel pump, thus causing the wire from the fuel pump sensor to lay directly on the bracket itself, which gets fairly hot. So I decide to unwrap and re-tape the wire itself and pull it away from the bracket. Then I put the car through an ignition cycle and the code popped off, and Onstar probe came back clear. The car seems to run the same, except I have been getting 33 MPG on back wood country roads doing about 60MPH with the cruise set in 5th gear.

My question is, could the contact from the heated bracket cause the wire to temporarily "short"? And my second question is, WTF am I getting 32-33 MPG after this?

 

what mpg did u get before this? when im going 60mph in cruse i get about 35-38. im sure id do more on a long road trip

 

well if it melted the insulation yea or caused a very high resistance due to the heat wouldnt be a short but a faulty signal and if youre MPG changed that much check youre a/f ratios

 

Well on those same roads...maybe 28-29 MPG. The MPG is not a big concern, considering I have seen 32-33 on the highway pushing 75. Just noticed that it was weird. What caught my eye concerning fuel, was when I reset the MPG AVG reading mid-drive for the first 3-4 miles I was seeing 45 MPG...after some shifts, slowing and starting, etc. then she dropped to 32-33MPG. BUT again, the MPG isn't so important, as to the reason why the fuel pump lost voltage...

As far as AF goes...no scan. The insulation was not melted at all. If you look at the pump and wire coming off you see its wrapped with a plastic insulator, but right when it meets the larger insulator, there is a tiny gap where the fuel pump wire feeds in with the rest of the wires. That's the exact place it was laying at on the bracket. But the wire was not burned through at all, I just decided to add extra tape just in case. And whats unusual is the car was not driven for almost 4 hrs. So it was somewhat cold. The only conclusion I can draw is that it got heated when I drove it, and it laid on the bracket while it was cooling...?