Hi all, ive been thanking that i need to change out my fuel pump (88 3.4), i started another thread but it kinda died before i understood what a pulsator was, so i apolige for the double post, so anyway i got 16psi at the shrader and like 22 while running, 30 with full throttle, im assuming that my pump is on the fritz, but what is this pulsator? any wright ups on how to replace/ fix this??
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09:35 PM
PFF
System Bot
Xanth Member
Posts: 6886 From: Massachusetts Registered: May 2006
Scrap it and put in a length of hose. I believe in theory it is to reduce the sound of the pump inside the car, but I feel its unnecessary. It is also one more spot where pressure can leak from the system.
The pulsator is directly between the fuel pump and the fuel assembly, if you've replaced your fuel pump before and have a pulsator you will have seen it.
On that page you will see a pic of the fuel pump assembly removed, you can just see the pulsator above the fuel level assembly. It has two bulges on the side. The fuel pump simply pulls out of it, and the pulsator pulls right off the assembly. Just replace it with a piece of fuel injection hose and clamps.
I've replaced the pulsators on both my Fieros and my C4 Corvette with a short section of fuel injection hose. Works perfectly. If it's noisier than before, I've haven't noticed. Then again, I'm getting up in the years and all those concerts in the 70's and 80's took their toll on my hearing
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11:43 PM
88 Silver Formula Member
Posts: 857 From: belleville il Registered: Feb 2007
WOW thats alot of rust in thoes pics lol, mine doesnt even have rust on the fuel tank strap studs lol, but ehhhh, ive heard that the pulsator keeps fuel constant because the pump jerks with each pump causing gaps in fuel, the pulsator acts like a negitave capacitor..and if you do by pass it..will it be louder?
This says to use non fuel injection hose. Wouldn't you want to use fuel injection hose? All Fieros are fuel injected as far as I know.
Non fuel injection hose ( rubber gas line) can rupture under the high pressures that EFI requires. Fuel injection hose must be used and you'll never notice that the pulsator is missing.
------------------ 87GT 3.4 Turbo- 0-60 5.2 seconds 2006 3800SC Series III swap in progress Engine Controls, PCM goodies, re-programming & odd electronics stuff " I'M ON THE LOOSE WITHOUT THE JUICE "
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10:51 AM
Xanth Member
Posts: 6886 From: Massachusetts Registered: May 2006
This says to use non fuel injection hose. Wouldn't you want to use fuel injection hose? All Fieros are fuel injected as far as I know.
That hose I have listed is not for the high-pressure outlet on the tank, it was for the smaller low-pressure return and vent lines.
I used to have the proper high-pressure line listed there as well, I must have accidentally deleted it. Anyone happen to know the correct size off hand?
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12:12 PM
Xanth Member
Posts: 6886 From: Massachusetts Registered: May 2006
WOW thats alot of rust in thoes pics lol, mine doesnt even have rust on the fuel tank strap studs lol, but ehhhh, ive heard that the pulsator keeps fuel constant because the pump jerks with each pump causing gaps in fuel, the pulsator acts like a negitave capacitor..and if you do by pass it..will it be louder?
And that's my good tank
As for the pump jerking, that may be true if it was a piston or diaphragm pump, but its not. I believe its called an impeller type? Might be wrong there but fuel flow should be fairly constant through this type of pump.
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"If any car is both the parade and the rain, it is the Fiero"
[This message has been edited by Xanth (edited 08-09-2007).]
