Removing fuel tank to replace fuel pump on GMC van questions

[Victor]

Excuse me for asking this question on an Infiniti forum but after searching the internet I have found very little information on the subject and much to my dismay I discovered the repair manuals I bought with my 1988 GMC van do not cover the fuel injected engine fuel system. I figure there are a lot of experienced guys here who may have done this on another vehicle, and I am guessing one would use about the same procedure for any vehicle with the fuel pump in the tank.But anyway, I have narrowed it down to a bad electric fuel pump that is inside the fuel tank. Some accounts I read say it typically costs around $900 to get this job done in a shop, but another guy said he did it by himself without a lift in four hours. Just looking at what needs to be done I would guess an experienced mechanic who had a lift and some thing to support the tank could probably do it in two hours. But anyway, here are my questions:1. Does the tank have to be drained before dropping it? One website showed some kind of machine for draining the tank, and another said that if the pump still worked, which mine doesn't, you could use the car pump to drain the tank by jumpering the control circuit and hooking a hose up to the fuel line. My problem is I have 3/4 of a tank of gas so the tank would probably weigh 200 pounds, that's a lot of weight to try to manuever around while laying on ones back under the vehicle. One person suggested putting a piece of plywood on top of a floor jack and use that to support the tank.2. If anyone ever paid to have this done what did it cost and how many man hours were involved? I checked fuel pump prices and they range from $49 on to as high as $260. 3. If anyone ever did this how long did it take and were you able to do it just using jack stands and a floor jack?BTW, this is the first time in 40 plus years of driving that I ever had to be towed.

[Infinitiguy19]

Are you sure there is no way to jumper (Ground) the Pump?

See if it some how runs so you can drain the tank by just letting the truck idle.

I would support the tank on four Jacks for stability.

[Victor]

I am almost certain the pump is bad because I disconnected the the plug going to it and I have 12 volts when I turn on the ignition key. I also tried applying 12 volts directly to the input terminal and no sound. I know it not a clogged fuel filter because I disconnected it and it was clean inside, and no fuel came out when I turned on the ignition key while it was disconnected.. I also checked the fuel pump relay by removing it and applying 12 volts to the coil and the contacts were opening and closing like they should. The oil pressure switch which is part of the fuel pump circuit also seems to be working properly. I also tried banging on the tank which some people recommended might start a jammed fuel pump.But anyway the van won't start, and I do have a spark.

[dllkbales1]

The banging on the tank usually works best if you bank on it with a large heavy hammer while someone is cranking the engine. When you pull the tank, less fuel is less weight and easier to handle. You could always put a hose in and siphon some of it out. To pull the tank spray everything first with penitrating oil. bolts clamps everything.If this tank is next to the driveshaft you may want to remove it for more working room.Loosen clamps on the fill hose and the vent hose, (the smaller on next to the fill hose). Spray a little oil in next to the tubes and work these hoses loose with a small screwdriver. Disconnect any hoses you can see coming off the tank and your wiring harness. There may be one place to disconnect off to the side of the tank or 2-3 seperate oned on top. Alot of extra hands will now become usefull. Support the tank on a floorjack, back off the bolts or nuts on the tank straps and bends them gently out of your way while balancing the tanks. If it falls things will break. Lower the tank slowly looking all over the top, you need to get everything loose. There will be a fill hose, vent hose for filling, fuel supply and fuel return (may require special tool), one or more hoses for the evap vent system to store fumes and burn them later. If you break it you must fix it our the check engine lite will come on and you will have an evap code. If you buy a good pump you will get the entire module assembly. The lines will most likey require special removal tools to release off the fuel module at the tank. You would put the tool around the fitting,slide it into the line to release the internal clips, push the line and the tool towards each other then pull the line off. Cheaper pumps may have to be put on the fuel module and then put back in the tank. The module will be held in the tank by a large snap ring or a ring you need to rotate of with hammer and punch. Clean this type well, blow out the dust and dirt before attempting to rotate, spray with oil. NO SPARKS PLEASE. A little vasiline on the o-rings and seal, lines and fittings will help it go together easier without damage to any seals. Damage a seal and this will be practice for the next time. Cheap pumps at discount stores have always failed during the warranty time that our shop offers. Its you time and money, chose wisely. Best of luck, Dave

[Victor]

Dave, or anyone else, from your answer I assume you either work in a shop or own a shop. Do you usually drain a tank before lowering it or do you leave the fuel in it? One problem I have is where to store the estimated 17 gallons of fuel in the tank, I only have a five and two gallon gas can, and they warn not to store gasoline in an open container. I would rather just leave it in the tank if possible. One idea I had was to put it into my J30T, but the van uses regular and the J30 uses premium so there might be a problem there, but I guess it wouldn't hurt just doing it one time. I also tried syphoning gas out of a G20 I was going to junk once and couldn't get any out, so I don't know how much luck I would have on the van.If my van requires special tools for the hoses that could be a deal breaker as far as doing it myself, unless they are something I could buy in any auto parts store.I was thinking of rolling a furniture dolly under the tank, and then putting several layers of wood on top of it to support the tank. I could pull a few layer out to lower the tank and then roll it out from under the van. Or maybe I could make some wedges out of wood.I also read the straps and bolts should be replaced when after dropping a tank, do pros usually do that and do they usually install a new strainer?

[dllkbales1]

Putting the gas in your other vehicle would mix the two to become a mid grade octane. Under normal non-abusive driving that should not be a problem. We have a storage tank with a hand crank to pull the fuel out, or to a lower level. Go get some clear plastic hose, several feet. Push one end into the tank while blowing on it. When you enter the fuel you will hear it bubble. Slowlt suck the fuel out untill it has traveled far enought out of the tank towards the ground till its past the lowest part of your van, then put it into a can. We never dicussed what year the van was but being fuel injected it will most likey have self locking slip on fuel lines at the tank. The tool to release them comes in a set, cheep plastic sets are available at most parts stores. 10 to 20 for the set.They will be a "C" shaped piece or a circle that hindges open , that you put around the fitting on the tank that the lines connects onto. They have a sleeve that enters into the end of the line as you slide it down the fiiting into the end of the fuel line. This sleeve spreads clips that catch on a ridge of the fuel pump modles fittings. As you slide the line and tool of the fuel module, the tool holds the clips spread untill it hits the ridge, by then the clips are past the ridge and the line slips off the fitting. When you arssemble, no tool is required, just push it on tills it snaps over the ridge. Attemt to pull in back off. If it feels solid, you are good. If the straps and bolts come off well and are not badly rusted to the point os structual weakening, I reused them. The screen is hit or miss, most of the time I would advise it, but the one they sell you seldome looks like what I find in the tank. I hope I have been of help and answered most of your questions. Dave

[Victor]

Follow up on GMC van fuel pump problem. I troubleshot the problem myself and was 99% sure it was the fuel pump. I called a GMC dealer and they wanted a rip off $932 for parts and labor to replace the pump and strainer. I called around, and most independent shops wanted around $330 to $380 parts and labor, plus I would have to pay an additional $50 to get the car towed to the shop. My car insurance only covers one tow per a disablement, so since the car broke down on a holiday and I had the car towed to my driveway since no shops were open I would have to pay for the second tow myself.But I was looking on Craigslist and saw ads for a bunch of mobile mechanics who come to you. One guy said he would drop the tank and change the pump for $100 if I bought the pump and strainer myself. I bought the OEM AC Delco pump for $67 and a strainer for $7 from an independent AC Delco distributor. The GMC dealer wanted $117 for the same pump.But anyway now I know how to drop the tank and change the fuel pump if I ever have to do it myself. The secret is to partially lower the full tank on a floor jack until you can take the filler hose off, and then syphon the gas out. Its almost impossible to syphon the gas through the gas filler pipe where you would normally tank up. I tried it and only managed to get a gallon out. BTW, the guy syphoned gas the old fashined way, sucking on the end of the syphon hose, getting a mouthful of gas in the process. An empty tank is actually very light.So anyway, the total job cost me $180, whereas it would have cost me as much as $980 if I had the car towed to a dealer. The guy also read the OBD II code on my daughter's 2000 Q45T for me, which was P158, indicating a bank 2 Oxygen sensor problem. He offered to change the two oxygen sensors for $160 parts and $40 labor, is that a good deal?