New fuel pump won’t idle

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Cam1399

Cam1399

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Hey I installed a new mechanical fuel pump in my 74 duster. 360. Now it won’t idle. It is a Delphi. Is there anything special when installing these pumps? Thanks
 
it is possible it may have to much fuel pressure and you need a regulator . check the fuel pressure .
 
Will be checking that next. Looks like the same pump that was on it. Arm was a bit different
 
Will not idle because of fuel pump ?? It should idle fine without a fuel pump as long as the fuel bowls are full and the floats are adjusted properly. The fuel pressure is regulated so it does not over power the needle/seat seal.
Idles with the choke on? , put your hand over the top of the carb when you start it. if it stays running you have a vacuum leak...
If it idles with the choke on, it is not a fuel pressure problem. The choke only restricts air into the throat of the carb making it run rich.
A lean condition idleing is going to be a vacuum leak if nothing else has been touched. Have you tried any adjustments to idle speed, a/f or timing after the pump replacement ?
Even to try to make it "idle?"
Give the whole story to right now...
 
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Ive looked at all the vacuum lines on carb and intake. Ran fine last week before I changed the pump. Changed pump due to it leaking down real fast
 
Cam1399 said:
Ive looked at all the vacuum lines on carb and intake. Ran fine last week before I changed the pump. Changed pump due to it leaking down real fast
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My Holley pump leaks down in about 10 minutes. Have AN lines and one of these days I’ll put in a one way AN check valve to stop of from leaking down. Other thing is fuel in the bowls will evaporate as the engine is cooling down. If ya don’t have a fuel pressure gauge and regulator in line after the pump, I’d add one...
 
Looked over vacuum again. Had a crack in the bottom of one of my caps on the carburetor sucking air. Idles now. I didn’t realize they leaked down that fast. But car sat for awhile before I got it. Trying to get it road worthy again. Thanks guys
 
Can you expound on "arm was a bit different"?
 
Cam1399 said:
They were the same length but new one was straighter than old
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And you installed it anyway? Sounds like a big block pump. They will bolt in the same place. No way would I have installed a different looking pump.
 
Both arms ended at same length and angle. Does anything come in contact on the middle of the arm?
 
RustyRatRod said:
And you installed it anyway? Sounds like a big block pump. They will bolt in the same place. No way would I have installed a different looking pump.
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Big block pumps are short armed and use a pushrod. Small block pumps are long armed and run right off the cam lobe. You knew that.
 
toolmanmike said:
Big block pumps are short armed and use a pushrod. Small block pumps are long armed and run right off the cam lobe. You knew that.
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Yeah that's right. I forgot. ....and I shouldn't have, because I'm getting ready to mod a big block pump to work on a slant 6. If it works, and it will, that'll be a good how to for our slant 6 brethren. In looking, there ARE small block pumps with different shaped arms. "I GUESS" all that matters is that last 3 or so inches is at the correct angle.
 
That’s what I was thinking too. I’m new to mopar cars. Grew up on gm but got this duster of my wife’s grandpas. Car is here and grandpa is gone so trying to get it dependable again. Thanks again
 
Cam1399 said:
That’s what I was thinking too. I’m new to mopar cars. Grew up on gm but got this duster of my wife’s grandpas. Car is here and grandpa is gone so trying to get it dependable again. Thanks again
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"IF" you end up removing the pump, just check to make sure the last bit of the arms on each is the same. It's probably the right one.
 
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