Fuel Pump Pulsator question
07-16-2007, 10:53 AM
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Fuel Pump Pulsator question
Replacing the fuel pump on my 84 with an 85 pump. The 84 does not have a pulsator, just a hose. Do I need to add a puslator to it??
Tom Shaffer
shaffermotorsports@zoominternet.net
Tom Shaffer
shaffermotorsports@zoominternet.net
07-16-2007, 11:42 AM
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Well...............guilty as charged. I only did it because I had it apart, the car has 80,500 miles and with my luck once I put everything back together it would fail.
Was getting very low pressure because the hose was split about 1/4 inch so I it was pumping fuel back into the tank. Was the pump weak? I don't know and the replacement was only 80.00 so if figure I got off cheap for a vette.
The issue is this: the new pump has a .318 Dia., the old pump is .375 so I'll have to get 5/16 hose and force it over the 3/8 dia fuel line so the 5/16 will seal off the exit on the new pump. Make sense??
Was getting very low pressure because the hose was split about 1/4 inch so I it was pumping fuel back into the tank. Was the pump weak? I don't know and the replacement was only 80.00 so if figure I got off cheap for a vette.
The issue is this: the new pump has a .318 Dia., the old pump is .375 so I'll have to get 5/16 hose and force it over the 3/8 dia fuel line so the 5/16 will seal off the exit on the new pump. Make sense??
07-17-2007, 08:10 AM
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I called the Auto parts store for them to double check the part number, it matches what I have and it listed for 85 - 88 Corvettes (the 84 is a different number). So what I did was I bought a piece of 5?16 diamter hose heated up one end in boiling water to soften it up. I slid this end over the exiting steel fuel line that is part of the sending unit assy. I then slid the fuel pump into the other end. What this does is it makes a transition between the two diameter's. The piece of hose is only 1 1/2 inches long.
The 85 diagram show something called a "Puslator" that takes the place of this hose. I don't know what the puslator does but I guess I may find out.
Tom
The 85 diagram show something called a "Puslator" that takes the place of this hose. I don't know what the puslator does but I guess I may find out.
Tom
07-19-2007, 03:40 AM
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You can, however, swap in a 85-91 pump into the 84 and it will work just fine. It will offer no performance gains over a properly working 84 pump though.
Pumps create flow....regulators (restrictions) create pressure.
It will still achieve only 13 psi maximum, as the fuel pressure regulator on the rear throttle body will keep it there.
It's a popular "upgrade" if the original 84 pump has failed. I did this when my 84 pump went bad for the simple reason as they both cost the same and the 85 pump was in stock (84 pump had to be ordered). Working fine for 2 years now.
07-19-2007, 10:50 AM
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EXACTLY!!!If you need a fuel pump for an '84, an '85 pump makes for a good replacement. However, if the '84 pump is performing up to spec, there is NO gain to be had in replacing the stock pump with one for an '85.
RACE ON!!!
07-24-2007, 10:22 AM
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07-24-2007, 10:43 AM
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Originally Posted by Sprint7677
Unless your plans are to change some things down the road
What is planned for down the road? Not a TPI, I hope.
RACE ON!!!
07-24-2007, 05:09 PM
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I just used the 85 pump because it cost no more than the 84 pump and I see on here that it would not hurt to go that route. Was not looking for any gains in HP, or overall performance
I could have re-used the original pump and just replaced the hose, but given the age, and my luck I figured while I have it out I might as well replace it. Heck it was one of the easiest things I had to do so far on the vette.
07-24-2007, 07:57 PM
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I don't believe in replacing good functioning parts unless they are a maintenance item. But since you've done it, the '85 pump is the right replacement for a failed '84 pump. There is an old wives tale that says switching to an '85 pump will provide a performance gain over the stock pump, kind of like the myth that the oil pressure switch is a low oil pressure safety cut off. I was trying to help by making sure you weren't wasting money on the '85 pump looking for a performance gain.
What do you mean by, "get the TB's redone"? They are easy to rebuild at home. Unless they are really gummed up and dirty, don't look for a performance gain there, either.
RACE ON!!!
What do you mean by, "get the TB's redone"? They are easy to rebuild at home. Unless they are really gummed up and dirty, don't look for a performance gain there, either.
RACE ON!!!
