Yes, Bosch may make a very good fuel pump, but the original pump installed in your truck came from one plant, Delphi. While at the Delphi plant, watching the plastic injection pellets heated and injected into the mold, seeing the pump assembled then magnetized , tested, inserted into the plastic bucket, the the sending installed, then re-tested before boxing, ensured me the quality that was incorporated into the process. A pallet of boxes where un-folded and the pump assembly went into an ACDelco box. After a while, the 8 pallets of freshly minted pumps went into a semi truck. At this point, Delphi boxes were used to be sent to warehouse distribution. I asked if the Delco units where going there as well. I was told no, their destination was the truck assembly plant in Oklahoma City for the Trailblazer, Envoy.
The different I know of, is the fuel sender's ceramic card. Instead of silver infused ink, silk-screened on the card, they switched to a higher content of noble metals including platinum, nickel, lead, gold or "Plainey 6" alloys in the ink to resist the formation of silver sulfide when the level of sulfur in fuel was not regulated. They used (bifurcated) multi-fingered sweeping contacts to reduce contact force while maintaining an excellent fuel level signal, that is also used for OBD-II for EVAP Op's for fuel levels from 10% - 80% of full before test for leaks. This also worked great with ethanol fuels up to 85%.
I can not say what Bosch uses for sender ink or the commutator plates on the armature that GM has formulated a change to work with E85 as well. My experience is aftermarket parts are copies using reverse engineering from the first design of the OEM product.
But using the "Broadcast Code" of ID will help, use of an "RFI" module will work as designed in your GM product. Change the external fuel filter on a regular basis is a no brainer.
You can also call ACDelco techline phone number, give them the "VIN" and they will tell you the part number that works, even with changes that update the pump assembly you spend so much money on. Or at least they had this phone service for years.
After changing the external filter and pump, I would inspect the pumps sock-type filters for condition, before just blindly sticking a pump in the tank. I hate doing things twice. If your pump is inside a plastic tank, it has two filters. The one inside, will require disassembly, but it is the bottom of the bucket and traps all the trash in your tank.
P.S. Return fuel from a fuel pressure regulator dumps into this bucket as well, not the tank. The plastic bucket design is not to increase the cost, but to comply with mis-fire regulations, keeping fuel around the pump when the tank is low and turning corners. All manufactures petitioned the C.A.R.B. to relax the mis-fire counter in 1997. Although cars fall into a different category that trucks, but this happens to trucks soon after parts for passenger cars change.
These are two designs as well. One is a simple bucket and the other can be identified bu see a small hose "Tee" off the top of the pump, then disappearing down the side to the bottom. This is a fuel bleed that goes into a brass "Jet Venturi" that creates a vacuum on the bottom external sock-type filter. This pulls fuel inside to the top of the pump, a float lifts, and dumps the excessive fuel into the tank.
Does the aftermarket do that?
