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Fuel pump replace - cut or drop

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Think I have a fuel pump failure.


What have people been doing as to the task:

Drop the tank or cut the floor to gain access.


2003 Savana extended cargo 2500 6-lug 5.3 340,000 miles.


I asked this in the appropriate section but I believe that the viewership is much greater here.

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Up here in MA, it's easier to cut - you'll spend more time breaking bolts, cutting straps, & sourcing parts than it wouId take to just cut the floor. Then you can fabricate a little door for future access ... but with the miles on that one my bet is you'll have other problems far before this pump fails.


Why GM doesn't do this from the start like Volvo & Subaru do, I'll never understand. I swear they love to watch salt-belt mechanics suffer ... :nonod:

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NOTE: Somehow when I post in this section

1996-2014 Chevrolet Express & GMC Savana


It does not appear.






Not sure what happened to my original post in this section, so I'm back doing a re-post..





Well, confirmed it is the pump.

Got voltage at the grey wire near the pump and zero psi at the schrader valve.


Since I'm working in the driveway and I don't fit under there like I did at one time, I'm gonna cut the floor. Been all over Google and can't seen to find any pics or writeups for cutting the floor.


Anyone here done it???

Edited by WaterBoyz
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I've seen people do it on a truck bed which makes no sense at all but this is a different story, as long as you cut in the right spot and make sure you don't cut any wires or lines and it doesn't bother you I say go for it cause your the one that has to deal with it. Make sure you have a bigger around piece of metal to put over the spot if you are going to screw it down and make sure you rust proof the bare metal with some primer or paint and you have some sealant such as RTV or something to keep water and fumes out. Good luck and give us an update.

Edited by Btuggle88
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  • 2 weeks later...

OK, got the job done.


Of course I made sure I had voltage at the wires at the pump before I started this adventure.

2003 @ 324,000 miles.


Here are some pics and comments.


I dropped the tank down some by backing off the strap bolts to near their end to get more room on the top.

Removed the two screws and one push-pin to let the inlet move down with the tank.




I put a wet towel on top of the pump area and used a cut-off air tool.
























Gasket on the left is the original.

Had a real biotch trying to get the metal ring to go on. I fiddled with the new gasket and shortened it and shaved it down and it got closer to the ring going on. Last thing I did was put some grease on the ring and the slide hooks and it went on muuuuuch easier.




Don't laugh ... that is what I had from a long ago project. Used different length screws depending on how much space there was. I did fasten up the tank straps before this step.




I added a bunch of quality duck tape to seal it as well. That pic I won't show you.




For over 2 years my fuel gauge never read correctly. Unlike a broken clock, this gauge was never right. Sometimes it would show MINUS 1/4 tank. I was hoping the new pump and sending unit would fix that but, alas, it appeared to be working correctly for the first day or so but is not correct again. Not as extreme but still not right.





As a side note...

The pump went out in my 99 dually while going down the interstate. That was a dealer done job.

The pump went out in my 90 Astro while in the driveway. That one I did.

The pump went out in my 98 Luminia while in the garage. That one I did just the pump.

Edited by WaterBoyz
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Having done this on a few GM trucks (so maybe my experiences don't apply) & a few GM cars and dropping the tank every time except once, if you were able to loosen the tank strap bolts enough to make a difference, why not just go ahead and drop the tank? Seems like it would have been less work than all the cutting, drilling, etc at least in this case.


Around 11 years and 300k+ miles and the top of the unit was that clean! Wow! Last one I did literally had wheat growing on it....


Still, good ingenuity on using what you had on hand for securing the flap back down!


Are you 100% positive the pump/sending unit was exact part number for your VIN? My good old 99' Silvy had, IIRC, 11 different GM part numbers for the pump/sending units on it. That gasket issue makes me wonder.


As far as the fuel gauge, I think there are some threads in here that can help point you in the correct direction.

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There was 25+ gallons of fuel and I had nowhere to put it. I'm getting older and my belt seems to be keeping up as well, so I don't fit as well as I did.


The last one I dropped was the Lumina. That had some plastic tubing fittings that I could touch but not see. Of course those were the ones that would not come apart. Thus some unorthodox repairs were needed. PITA it was.


As to the gasket, the original was very sloppy fit to the pump. The new would not interchange nor the old to the new. After awhile I lost track and just was head-strong to get the ring on.


I bought that pump off Ebay many many moons ago and did the best I could researching the part number. It was a GM pump.


My next mission is to do the knock sensor since it is tossing a code now. Then, maybe I'll dig into the fuel level issue. I've gotten used to used the trip-o-meter as the fuel gauge.


As for the flap hold-downs, the last time we moved it took me 10 weeks. Took the wife a week.

So yea, I've got STUFF.

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