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AIRTEX Fuel Pump doesn't pump enough fuel. Two years blaming everything except the weak fuel pump.


48ply1stcar

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Did a volume test on my car after trying everything else.  Low volume, weak stream, relatively new pump.  Is there a way that I could be wrong on the cam or to the side? I bought, this fuel pump in 2015 reinstalled it in 2016 after rebuild.  I have tried to figure out why my car doesn't go over 55 for two years.  Now do I buy another, complement with electric, try another brand, or rebuild?

Edited by 48ply1stcar
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One check to try-

Is the arm pivot pin still centered and not coming out of the casting ? , which could make a big difference.

 

DJ

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Have you tried putting mild air pressure on your gas tank and line to the fuel pump to see if there are any pin holes causing it to lose suction?

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As Dr said I don't believe you can install the pump incorrectly and have it function at all. Not sure you can even install it incorrectly and have it not function. So that leaves restriction in the line somewhere, sucking air somewhere, or a weak pump. Do you have new fuel lines? Do you have fuel filters somewhere? 

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I found out a while back that some actually run on the top of the cam and also work. Not many I'll admit but it came off a Mopar truck my friend had and sold the pump to me.

 

When I got home with the used pump and started to look at this used truck pump and compared it to the one I had I took it back to my friend and insisted on money be returned.

 

He told me it will work just fine but gave my money back. Later found That I WAS WRONG, some did ride on top of the cam. Why some were made that way??

 

Were these pump trucks only at some time??

 

DJ

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if i remember correctly there is a lobe onthe crankshaft the crankshaft rotates and makes contct witht he arm on the fuel pump and this creates the  pumping action to draw fuel up from the fuel tank so when looking at your engine from the fron the fan is rotating  in a counter clock wise manner  not clockwise so the lobe on the cam is actually  coming top down on the lever not bottom up so the pushing downward creates the  pumping action.

 

rich Hartung

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You can try pumping the fuel out of a container other than your gas tank . See if the volume increases . Sometimes the line inside the tank gets plugged with rust or junk and can be augered out with an old choke cable housing spun with a drill .  

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18 minutes ago, Jerry Roberts said:

You can try pumping the fuel out of a container other than your gas tank . See if the volume increases . Sometimes the line inside the tank gets plugged with rust or junk and can be augered out with an old choke cable housing spun with a drill .  

I failed to mention that the test today was from a gas can under the fuel pump with a new fuel line.

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1 hour ago, desoto1939 said:

if i remember correctly there is a lobe onthe crankshaft the crankshaft rotates and makes contct witht he arm on the fuel pump and this creates the  pumping action to draw fuel up from the fuel tank so when looking at your engine from the fron the fan is rotating  in a counter clock wise manner  not clockwise so the lobe on the cam is actually  coming top down on the lever not bottom up so the pushing downward creates the  pumping action.

 

rich Hartung

the fuel pump is operated from a camshaft lobe specific for the fuel pump

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  • 48ply1stcar changed the title to AIRTEX Fuel Pump doesn't pump enough fuel. Two years blaming everything except the weak fuel pump.

I have had issues with Airtex pumps not pumping enough. There is no decernable wear on the cam 41 Windsor, but the stroke is just not long enough (pump shoots out fuel when activated by hand). I have a used fuel pump out of an industrial 251 and it had an added weld where the arm runs on the cam. Again no wear felt on that cam as well, I'm wondering if these newer pumps don't have a long enough pump stroke?

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9 minutes ago, 1949 Goat said:

I have had issues with Airtex pumps not pumping enough. There is no decernable wear on the cam 41 Windsor, but the stroke is just not long enough (pump shoots out fuel when activated by hand). I have a used fuel pump out of an industrial 251 and it had an added weld where the arm runs on the cam. Again no wear felt on that cam as well, I'm wondering if these newer pumps don't have a long enough pump stroke?

Two days ago my wife's 85-year-old uncle told me they did that to jeeps in his Berlin Motor Pool in the mid 50's. Did you just add a bead along the top?  By chance did you take a picture?

Edited by 48ply1stcar
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I'd dismantle the pump and make sure there is no rust or other residue from the tank keeping the valve partially open. Agree with  clogged fuel line as mentioned above but sounds like you already bypassed that.

 

One last thought, do you have the correct gasket between the pump and block? If for some reason the gasket is too thick it will move the arm away from the cam, effectively shortening the throw.

Edited by vintage6t
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I bought a new pump for a Chrysler industrial engine probably 30 years ago for my 54 Plymouth and have had no more fuel pump problems since.  

Prior to that, I had low fuel pressure problems that i thought were vapor lock, etc.  I had tried rebuilding my original pump and tried buying a rebuilt pump.

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did you really expect anyone or any company taking responsibly for the lack of performance of their product...I was looking for nevernever land in their e-mail address...

 

Trust me, it is just not this company...it is about all of them these days....money back guarantee means just this, they are satisfied with having got your money and guarantee you are not going to get it back...

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I ordered a pump for my Studebaker truck.  When it arrived it was an airtex.  I inspected the lever and pivot pin area closely.  I observed that there was a collar of metal surrounding one end of the pin.  This metal was obviously from the cast body of the pump.  Neither end of the pin hole was staked, so there was nothing holding in the pin in but force of habit.  I called their tech line and explains the situation to one of their technical people.  He stated it was nothing to worry about as the hole was smaller than the pin and was pressed in by machine and was reliable, he stated they had never had complaints regarding pins moving or coming out.  So I asked him how pressing in a pin of x diameter into a hole of x-y which effectively made the od of the pin and the "id" of the hole the same diameter evidenced by the displaced metal, made the pin stay in?  He had no answer except to repeat that they were unaware of problems related to pins moving or fallng out.

So I have fashioned a sheet metal clip that slips over the pin, and should keep the pin from moving.  A check of the clip every once in a while gives a bit of piece of mind that the pin is still there doing it thing.

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4 hours ago, The Oil Soup said:

You did mount the pump with the glass bowl on the bottom?

Yes unlike all of the ads showing the glass on top.  I never this problem until my NEW fuel pump for my rebuilt engine.

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24 minutes ago, greg g said:

Still have the old one???? Give it another shot.

When I bought this 1956 engine the outer case of the fuel pump was broken.  I still have the pump from the 53 engine but is needs to be rebuilt.  It's been apart on my work bench for years.

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Airtex has always been crap.

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well my turn

my father was an International  Harvester mechanic for many years,

We purchased a Triumph station wagon 1959 model. Very few parts available here in CA .

When he got it running it starved for fuel. I did not understand what he did until recently. The mechanical fuel pump would not follow the cam lobe.

He simply put in a stronger spring. 

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