Surely the fuel gauge going "backwards" wouldn't be a reinstall problem. Just reverse two wires going to the fuel gauge. Or put E and F stickers over the scale on the gauge.
When I was first stumbling into this problem, it went like this:
I got home from my emergency repair and took the RV into my usual local mechanic. He's convenient because his shop is directly across the street from the storage place where we store our RV, so he can just go get it when he has a time lot to work on it.
Originally, we were working under the assumption that the electrical short had not only burned up the pump but also the fuel gage. He wasted some time trying to hunt down a replacement gauge or an aftermarket fuel gauge.
After he got into it he discovered that the "fuel pump was defective and he has seen this before". He thought that the sending unit on the pump had been installed "backwards". He said removed it, flipped it over, and re-attached it to the pump. He said he had seen this before and that the pumps were manufactured wrong. In fact, he was wrong.
However, what he did
did make the gas gauge start working again. However, it doesn't work right. My guess is the rheostat/potentiometer in the sending unit is not calibrated properly running backwards. So when absolutely full the gauge only reads about 3/4 full, and it very quickly runs down to the E and sits there for most of the tank of gas. I don't know if he reversed the wires or if he really re-mounted the sending unit.
Anyway, I called Airtex to complain, and that is when I got into the heart of the problem. It's not that the pump was manufactured wrong, it was that their database spits out the wrong pump part number for my VIN. So did the AutoZone web site.
When I first emailed Airtex, they said that the problem was that the VIN was not accurate and that sometimes the chassis date did not match the RV manufacture date. This turned out to be incorrect. The VIN number
absolutely identifies the rolling Ford chassis. It is true that often RVs are built with last-year's rolling chassis, but that has nothing to do with the rolling chassis nor its VIN nor its identification.
After digging around on the web and other parts-locator web sites, I started to see that there was a cut-off date in 1990, I think it was around September, where before that date one part number was given and after that date another part number was given for the fuel pump.
After months of emailing Airtex they finally sent me the correct fuel pump for my RV for free.
So I spent $800 for the emergency repair when the pump burned up to have the wrong pump put in, and then I spent about another $300 with my local mechanic debugging and partially fixing the problem. So I'm already $1100 in. And it's going to cost me probably another $300 to have the "free" correct fuel pump installed.
On one hand I feel like I probably should have sued the original mechanic. Even though it was virtually impossible for him to know about the problem, I did take the RV right back to him after I stopped for gas after leaving his place and noticing that the gas gauge did not work. But he kind of blew me off when I returned to the shop and said, "Yeah, ok we'll look at it." I could tell when I left that he probably wasn't going to look at it and was just going to say, "we can't fix it the gauge must be fried."
Sure enough a week later he said they could not figure out what was wrong. I don't think they ever checked. If they had done some investigating and some googling on "gas gauge not working" or "gas gauge works backwards" they would have gotten a clue that they had the wrong pump.
The moral of the story here is this, folks: If you get your fuel pump replaced and the gas gauge doesn't work, you need to assume the wrong fuel pump was put in.
Steve
