I'm in the middle of replacing the original fuel pump in my Formula ('88) and came across a small but important issue. Many, if not all, original Fiero port-injection fuel pump installations incorporated a "pulsator" just downstream from the pump, and there is a small rubber "pad" or "isolator" that goes between the pump and the pulsator.

It may be OK to leave out the pulsator when replacing the pump ... Delphi includes a short piece of rubber hose for just this purpose ... but I chose to retain it. Unfortunately, while new pumps, pulsators, and strainers are readily available from Delphi/Delco, the rubber isolator is not. The problem is that the original rubber isolator is not compatible with the new-style fuel pumps.

Here is a picture of the original rubber isolator and fuel pump. Note the two round plastic plugs to the left of the fuel outlet tube. These plugs are approximately flush with the pump body.



Here is a picture of the new-style rubber isolator and fuel pump. Note the two raised metal bosses (probably electrical terminals) on the new-style pump in place of the two flush plastic plugs on the original. These raised bosses extend about 1/8 inch above the body of the pump. Note also that the new-style rubber isolator has a recess molded into it to provide clearance for the raised bosses.



Finally, here is a picture of the new fuel pump, rubber isolator, and pulsator assembled. Note how the recess in the rubber isolator provides clearance for the raised bosses on the pump.



If you are going to replace your fuel pump and want to retain the pulsator, you need to buy a new-style rubber isolator. The problem, as I said earlier, is that the rubber isolator isn't readily available. Your local parts store can order you a new pump, pulsator, and strainer from Delphi/Delco, but as far as I know the rubber isolator is only available from directly from a GM dealer or a Delco distributor, and even then very few of them stock the part. Here are the part numbers ('88 V6) for reference:

Pump --- Delphi FE0113 (Delco EP378)
Pulsator --- Delphi FA0001 (Delco FP27)
Strainer --- Delphi FS0001 (Delco TS1)
Rubber Isolator --- GM/Delco 25004553 (dealer only)

Would the original isolator have worked with the new-style pump? Maybe. Was I willing to drop fuel the tank a second time if it didn't? No. I hope this information will help somebody out in the future.


Edit to add a better picture from Delco of the new-style rubber isolator:

[This message has been edited by Marvin McInnis (edited 07-21-2006).]

Not directly related, but I cant find any in tank rated fuel line at ANY of the car part stores around here, I need a peice longer than what came on my 4cyl fuel pump to install my walbro.

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https://www.fiero.nl/forum/Forum2/HTML/072877.html