1. Disconnect battery
  2. Remove the lid on the rear deck of the car. Remove the fuel filler cap. Slide the rubber boot over the fuel filler neck. Be careful not to tear the boot. Remove the 10 or 12 bolts that attach the fuel filler neck to the tank.
  3. Grab the fuel filler neck and carefully twist and lift the pumps out of the tank. The pumps are all attached to the fuel filler. Be careful not to bend the rod on the float for the fuel filler gauge. Make sure to install new fuel strainers on bottom of pumps.
  4. When you remove the old pumps from the module, and install the new pumps make sure you use new clamps and that all of the rubber hoses that connect to the fuel pumps are in good shape and be careful not to crimp any of the hoses that would restrict fuel flow. Also get an ohm meter and check the resistance on all of the wire connections to make sure the pumps are getting current.
  5. When re-installing you have to carefully twist and turn to get the pumps and the pump housing installed back into the tank. Once you get everything in the tank firmly push down to seat the fuel strainers on the bottom of the tank. make sure to use a new gasket where the fuel filler neck bolts to the tank and tighten it up.
  6. Did not notice any fuel mileage degradation cruising around. Noticed a big difference running balls out.
  7. However I had a weak secondary pump to start with.
  8. Once you get it back together do a fuel pressure check as follows:
    1. Remove primary pump fuse on side passenger side panel. Attach fuel pressure gauge. Turn ignition on (but don't start motor) this tests the secondary pump. You should have about 50 to 60 psi. Before I replaced the pumps I only had 38 lbs on this pump. After replacing the pump I had about 55 lbs of pressure.
    2.  Bleed off pressure from gauge. Reinstall primary pump fuse. Remove secondary pump fuse. This is under the passenger side of the dash board. It is a bitch to get at. Read the owners manual for more details on this fuse. Do the process I mention above to test the primary pump now. Before I replaced the pump I had 45 lbs, now this pump has 55 lbs as well.
  9. Last change the fuel filter. It is on the underside of passenger side of car.
With engine running fuel pressure should be at or around 42 to 50 psi.
Fuel Pump part numbers:
GM Part #25163473 ($72) *Fits '96 Suburban with 454 Engine
Airtex - E3904 ($69) (800 424 7839)
Master- E3265 ($69)
Neihoff - P36 (it also has BWD P36 on it) ($65)
I would recommend the Master brand over the Airtex but if you can get the Neihoff do that. It's internal parts are all metal. The Airtex one failed on me a month after putting it in. It also has a wiring harness change over you have to do. The Master and Neihoff are a drop in replacements.
As per Scott Fabre
Also note you can buy fuel pumps at most auto parts store like Autozone which sells them for $50-$65. The part number is 3940 however the 3904 has a different electrical connector than the original pump. You can use the 3265 which is the replacement for the LT1 engine, but it has the same connector as the original LT5 pump. They also have the sock filters as well. They are made by airtech. Airtech supplies them for GM and GM stamps their own delco logo and part number on them. You can also use 3270 part number as well.
Author: Glenn Richardson
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