97 Astro Fuel Pump Replacement - Hints (Long Post)

[QDH Dale]

I bought a 1997 Astro AWD conversion van a few months ago. I use it for camping, ham radio contest expeditions in the mountains, and to pull a 19ft boat. It has a ton of miles (170K) but came in great condition. Included were the repair records from mile zero. I did not find any evidence that the fuel pump had ever been changed, and as it was making a noticeable whine and I had nightmares of getting stuck on a forest road 30 miles from nowhere, I decided to do a pre-emptive fuel pump change in the comfort of my driveway. I did it the conventional way by dropping the tank, but I also added a floor access plate in case I ever have to do it again. Since the forums mention fuel pump failures as a common occurrence, I'll provide a few hints of my experience in case it is of help to anyone else out there.

First a gripe, and lots of others have said the same thing: why in the world GM did not provide an access plate in the floor is beyond me. I figure it would have cost GM about $5 to provide this feature. Every Japanese or Korean car I've owned always has a fuel pump access plate located under the rear seat or in the trunk floor over the tank. I have a theory that GM and the car dealers conspire to purposely make owner repairs very difficult because it is immensely profitable to the dealer service dept. The non-American brands are often sold in third world countries; I've seen a lot of major repairs made alongside the road in Asia, S. America and Africa, and the Japanese brands seem to be a bit friendlier for this activity. But enough of that.

There are YouTube videos showing how to bore a hole through the floor to access the pump without having to drop the tank. It's not a bad idea, but it's hard to know exactly what's where when you're cutting away the floor. So instead I dropped the tank. It's not as difficult as I imagined. I drove the rear wheels up on car ramps and left the front wheels on the ground; you need enough room to pull the tank out from under the van. You can use the scissor jack that comes with the van to support and lower the tank. I would advise against trying this with a full tank. If you have anything less than a full-up tank, you can pull the fill hose off the tank and then insert a siphon hose and drain it from there without gas pouring out of the fill fitting. Hint - remove filler door and plastic inside plate to create enough wiggle on filler hose before attempting to pry it off the tank fill fitting. I still had about 3 gals in the tank when I dropped it and it gets a bit tippy while you're lowering it because the fuel sloshes to one end or the other. Just be prepared for this. The three pump fuel lines are located above the driveshaft and are accessible once you remove the plastic shield between the tank and the driveshaft. Hint - the shield is held to the frame with plastic insert connectors. Pry out the middle button with a small screwdriver and then you can easily pull them out. Push the shield over against the driveshaft. The fuel hoses on mine can be removed by pressing the two tabs on each side of the plastic connectors - no special tool was required. Hint - you don't need to try and disconnect the pump wiring connectors before lowering the tank. The wiring harness is long enough to drop the tank and actually pull it out clear of the van while still connected. The pump on my 97 uses a large snap ring to secure it on the tank rather than the cam ring I saw on some YouTube videos. Easily removed with snap ring pliers. Replacing the old pump with the new is a 5 minute piece of cake.

Since the tank was already removed, I decided to make an access hole in the floor for "next time" (which pretty much guarantees this pump will never fail). So here are some hints if you decide you want to bore a hole in the floor. The fuel pump is located exactly in the middle of the tank. It is midway between the tank support straps fore and aft, and midway across the width of the tank. There are no frame beams to worry about. It's always a bit tricky translating what you're measuring under the vehicle to where this is inside the vehicle, but if you're careful and clever you should be able to figure it out. Hint - there is a fairly heavy stamped steel shield between the floor and the top of the tank. This protects the hoses and wires so if you're careful, you probably won't get into trouble. There is a bit of clearance between the floor and this shield but don't use a long blade. A cutting wheel or metal nibbler would probably be best if you're trying this without dropping the tank. A 10 x 10 inch access square centered over the pump will be plenty of room to remove the pump. Hint - on my van, under the carpet and above the corrugated floor there is a heavy plate for the seat anchors. I don't know if this is standard from GM or whether it was added by the conversion company when they installed the middle row of captains chairs. If you have a standard cargo van and are looking at the original corrugated floor, you have it easy. For me, I had to cut through both the heavy steel plate and the floor. A jigsaw did it but it took a lot of time. And again, I had already dropped the tank so I wasn't worried about hitting the top of the tank with the blade. I plugged the hole in the floor with a scrap of sheet metal and short self-tap screws. I used foam weather stripping between the sheet metal cover and floor to seal it. Put the carpet back and you'll never know it's there. Be a nice guy and put a small label FUEL PUMP ACCESS PLATE on the inside wall near the floor for the next person who has to replace the pump.

Some final caveats: I am describing a 1997 Astro conversion van. I "think" it is a standard cargo van from GM that went to the conversion company where they added the nice interior, thick carpet, panoramic hippie windows, TV, etc. I've got to believe all these vans are pretty much the same, but if you have a passenger van or a different year, well, no guarantees; take the above with a grain of salt.

Good luck
dale

[2001Astronaut]

Thanks for the how to on fuel pump replacement. Haven't needed it yet, but if I do I'll follow your lead and make a hole in the floor. As you say that almost guarantees I'll never need it