How do you replace a fuel pump on an 89 Isuzu Trooper?

Answer 1

not too hard. You need a bucket, 12mm socket, 17mm socket extension, offset box end, a jack, phillips screwdriver, vice grips.

If possible run the tank dry. If not place the bucket below the drain [plug in the tank and drain the gas out. Hopefully the bucket is large enough to take all the gas. You really don't have to drain it all but at 6 or 7 lbs per gallon it gets heavy. You got to remember it is gas and will burn so no sparks, no smoking no hot exhaust etc. Care is paramount. If you can drain all the gas you might as well clean out the tank too by adding a bit more and sloshing it around then drain again. Dirt clogs the little filter and starves the pump. Also if you run your tank low for a while the pump overheats and can fail.

First, using the 12mm remove the tank shield and set aside.

Then find the sending unit and fuel pump plugs located on the passenger side of the tank. The big one is the pump. Unplug it and reach up over the tank to undo the clips.

Next loosen & remove the tank bolts (3) on the driver's side of the tank and let the tank flop down on that side. You can use the floor jack to lower the tank slowly. It will also help hold the tank up when you are working on the bolts. The three need to be held from above using the offset box 12mm wrench.

Once these bolts are removed and the tank is flopped down on the drivers side you can see the 9 or so screws holding the pump assembly in.

First remove and plug the two neoprene lines going to the pump. You can use a pair of needle nose pliers to remove the clips. These are 3/8 lines and you need plugs handy or you will get wet.

Once the lines are out of the way you can attempt to remove the screws. First with the Philips #2 stubby and when that doesn't work with the vice grips. Just work slowly and carefully. Keep track of where the hose connectors pointed maybe by marking the plate.

Once you get these all out you can remove the pump assy.

The new pump will come with a new filter. Take the whole thing to the parts store to see exactly what you need to do to replace the pump. It is pretty easy and self evident. You might need to buy a few extra screws too. I usually replace the Philips with hex head.

Te install the pump assembly, jack the tank about 1/2 way up and reinstall the fuel lines. Jack it the rest of the way and reinstall the three bolts on the drivers side. You may have had to buy a bolt or two as these freeze and twist apart if you do remember the standard hex nut for a 12 mm bolt is 13mm

Reconnect the pump connector and start the engine after you clean up the spilled gas. It should work if you remembered to fill the tank.

Remove the jack, replace the tank cover and you are on your way.

You may want to replace the line filter (in front of the rear passenger side wheel along the frame while you are at it.

The procedure is the same for any trooper from 87 to 94 and probably all others.