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Wierd fuel pressure problem #709255
05/27/10 11:14 AM
05/27/10 11:14 AM
Joined: Jan 2003
Posts: 21,064
Niles , Ohio
T
therocks Offline OP
oh wait.but hey.lets see.oh yeah.
therocks  Offline OP
oh wait.but hey.lets see.oh yeah.
T

Joined: Jan 2003
Posts: 21,064
Niles , Ohio
Had the 440 out last week.Fuel pressure started to drop.Went to probally 3 to 4 psi.I figured maybe the Holley mech pump was going.Put my Carter hipo pump on.Started it and had 6 psi.Took it out last night and pressure was 3 to 4 and goiing to 1 at 50 mph.Today I hooked up my test gauge and had 4 to 5 psi idling.Id think the rod.Only thing I cant figure is why it had 6 to 7 when I first hooked up the Carter.I have great flow from the tank witj 3/8 line.Thought maybe my Auto meter gauge was bad but I doubt my test gauge is also.Just seems at 1 to 2 psi my Dominator would run out of fuel.So do you think the push rod might be bad?Whats the OE length?Rocky


Chrysler Firepower
Re: Wierd fuel pressure problem [Re: therocks] #709256
05/27/10 11:18 AM
05/27/10 11:18 AM
Joined: Nov 2004
Posts: 843
Suffolk,VA
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ireland383 Offline
super stock
ireland383  Offline
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Posts: 843
Suffolk,VA
OE is 3 1/4 inches. How is your fuel line? Do you still have the winter blend in it?

Re: Wierd fuel pressure problem [Re: ireland383] #709257
05/27/10 11:27 AM
05/27/10 11:27 AM
Joined: Jan 2003
Posts: 21,064
Niles , Ohio
T
therocks Offline OP
oh wait.but hey.lets see.oh yeah.
therocks  Offline OP
oh wait.but hey.lets see.oh yeah.
T

Joined: Jan 2003
Posts: 21,064
Niles , Ohio
Fuel line is all great.Has just had gas in it.I put 25 bucks worth in last week.Was empty or almost there a month ago.Rocky


Chrysler Firepower
Re: Wierd fuel pressure problem [Re: therocks] #709258
05/27/10 11:36 AM
05/27/10 11:36 AM
Joined: Nov 2004
Posts: 843
Suffolk,VA
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ireland383 Offline
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ireland383  Offline
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Suffolk,VA
What I found happening on my car was the header was close to the mechanical pump and boiling the gas at it. What's weird is it didn't happen last year. I also found a worn fuel pump pushrod that same season. I wound up going to electric. Check the length on the rod and report back.

Re: Wierd fuel pressure problem [Re: ireland383] #709259
05/27/10 11:54 AM
05/27/10 11:54 AM
Joined: Jan 2003
Posts: 21,064
Niles , Ohio
T
therocks Offline OP
oh wait.but hey.lets see.oh yeah.
therocks  Offline OP
oh wait.but hey.lets see.oh yeah.
T

Joined: Jan 2003
Posts: 21,064
Niles , Ohio
Pulled the rod its just shy of 3 1/4 inches.My mics are in my big box and I can get to them.My headers are pretty much away from the pump and lines.Been on for 20 years and never had amy proble.Even cold the pressure is down.Im wondering if the sock might be a problem.Its new as is the sender only like 3 years and 3/8s.I did notice on the cam side the rod looks like it might be mushrooming a bit.Its real shiny the pump side is only shiny on one part.Rocky


Chrysler Firepower
Re: Wierd fuel pressure problem [Re: therocks] #709260
05/27/10 12:02 PM
05/27/10 12:02 PM
Joined: Feb 2005
Posts: 28,312
Cincinnati, Ohio
Challenger 1 Offline
Too Many Posts
Challenger 1  Offline
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Joined: Feb 2005
Posts: 28,312
Cincinnati, Ohio
Quote:

Pulled the rod its just shy of 3 1/4 inches.My mics are in my big box and I can get to them.My headers are pretty much away from the pump and lines.Been on for 20 years and never had amy proble.Even cold the pressure is down.Im wondering if the sock might be a problem.Its new as is the sender only like 3 years and 3/8s.I did notice on the cam side the rod looks like it might be mushrooming a bit.Its real shiny the pump side is only shiny on one part.Rocky




I'd try a new push rod. My

Re: Wierd fuel pressure problem [Re: Challenger 1] #709261
05/27/10 12:09 PM
05/27/10 12:09 PM
Joined: Jan 2003
Posts: 21,064
Niles , Ohio
T
therocks Offline OP
oh wait.but hey.lets see.oh yeah.
therocks  Offline OP
oh wait.but hey.lets see.oh yeah.
T

Joined: Jan 2003
Posts: 21,064
Niles , Ohio
I think Ill go over the other garage and get one of my old ones.I know the OE one I pulled was good.This is a MP one I bought probally 11 years ago.It dosent have maybe 5000 miles on it.Rocky


Chrysler Firepower
Re: Wierd fuel pressure problem [Re: therocks] #709262
05/27/10 12:09 PM
05/27/10 12:09 PM
Joined: Nov 2004
Posts: 843
Suffolk,VA
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ireland383 Offline
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ireland383  Offline
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Posts: 843
Suffolk,VA
Both sides of the rod should have a 45 degree bevel around the outer edge. Try to get an exact measurement.

Re: Wierd fuel pressure problem [Re: Challenger 1] #709263
05/27/10 12:10 PM
05/27/10 12:10 PM
Joined: Dec 2003
Posts: 531
USA
5
540DUSTER Offline
mopar
540DUSTER  Offline
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Joined: Dec 2003
Posts: 531
USA
fill the fuel bowls,disconnect fuel line from carb,start engine with fuel line in a empty gas can and see how much it pumps in 15 seconds.BE CAREFUL AND HAVE FIRE EXT. AT HAND! Also a helper is good to have on the ing. key just in case.

Re: Wierd fuel pressure problem [Re: 540DUSTER] #709264
05/27/10 12:16 PM
05/27/10 12:16 PM
Joined: Jan 2003
Posts: 21,064
Niles , Ohio
T
therocks Offline OP
oh wait.but hey.lets see.oh yeah.
therocks  Offline OP
oh wait.but hey.lets see.oh yeah.
T

Joined: Jan 2003
Posts: 21,064
Niles , Ohio
I had it running with my test gauge on it earlier.Still only had like 4 psi.One side looks beved one looks smooth.My fuel filter and bowls were still full even with low pressure.Rocky


Chrysler Firepower
Re: Wierd fuel pressure problem [Re: therocks] #709265
05/27/10 12:22 PM
05/27/10 12:22 PM
Joined: Nov 2004
Posts: 843
Suffolk,VA
I
ireland383 Offline
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Suffolk,VA
Stick it next to the OE one and check the difference, then put the OE one in.

Re: Wierd fuel pressure problem [Re: therocks] #709266
05/27/10 12:22 PM
05/27/10 12:22 PM
Joined: Nov 2004
Posts: 9,312
SoCal
68HemiB Offline
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68HemiB  Offline
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Posts: 9,312
SoCal
Quote:

One side looks beved one looks smooth.




My money is on the aftermarket push rod starting to go south. You hang around here enough to have read the sob stories of crappy push rods, and the solution is always to dig out a decent original one. Which it sounds like you are on the road to doing already.


Down to just a blue car now.
Re: Wierd fuel pressure problem [Re: 68HemiB] #709267
05/27/10 03:12 PM
05/27/10 03:12 PM
Joined: Jan 2003
Posts: 2,521
Richmond Va, KeislerTKO 60...
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VanishPt Offline
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Posts: 2,521
Richmond Va, KeislerTKO 60...
Vacumn in the tank ? loosen the cap and see if you hear a WHOOOSH

Re: Wierd fuel pressure problem [Re: 68HemiB] #709268
05/27/10 03:14 PM
05/27/10 03:14 PM
Joined: Jan 2003
Posts: 21,064
Niles , Ohio
T
therocks Offline OP
oh wait.but hey.lets see.oh yeah.
therocks  Offline OP
oh wait.but hey.lets see.oh yeah.
T

Joined: Jan 2003
Posts: 21,064
Niles , Ohio
Well I was going to get an old one.One of my sons locked the door at the other garage and I dont have a key.So now I have to wait for one of them to get my tall ladder and go thru an upstairs window.That or hope one of the dummys have a key.My sons buddy rents the house and I have the garage and never lock it.Figure out why kids do stuff.Worst part is they are in their 30s.Rocky


Chrysler Firepower
Re: Wierd fuel pressure problem [Re: therocks] #709269
05/27/10 11:06 PM
05/27/10 11:06 PM
Joined: Feb 2005
Posts: 4,884
Michigan
MNobody Offline
master
MNobody  Offline
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Joined: Feb 2005
Posts: 4,884
Michigan
Buddy had the same prob, gas tank vent was plugged. Try loosening your gas cap.

Re: Wierd fuel pressure problem [Re: MNobody] #709270
05/28/10 01:11 PM
05/28/10 01:11 PM
Joined: Jan 2003
Posts: 21,064
Niles , Ohio
T
therocks Offline OP
oh wait.but hey.lets see.oh yeah.
therocks  Offline OP
oh wait.but hey.lets see.oh yeah.
T

Joined: Jan 2003
Posts: 21,064
Niles , Ohio
I found one of the old ones.Ill put it in later and see what happens.It looks like it might be just a tad longer than the one I pulled.Hopefully it will fix the problem.Rocky


Chrysler Firepower
Re: Wierd fuel pressure problem [Re: therocks] #709271
05/28/10 02:00 PM
05/28/10 02:00 PM
Joined: Nov 2004
Posts: 843
Suffolk,VA
I
ireland383 Offline
super stock
ireland383  Offline
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Joined: Nov 2004
Posts: 843
Suffolk,VA
Good luck, soak the cam end of that rod with some good oil with zinc or additive. I'm sure you already know that.

Re: Wierd fuel pressure problem [Re: ireland383] #709272
05/29/10 04:08 AM
05/29/10 04:08 AM
Joined: Nov 2009
Posts: 520
New Zealand
nz383man Offline
mopar
nz383man  Offline
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Posts: 520
New Zealand
Yes you should replace the rod if it is shorter than 3 1/4" but the pump should still hold pressure with a rod up to 1/4" shorter & if it dosn't you have other problems as well.
If all else is good & you are getting a full stroke on a good pump it will run down to about 3/8" shorter than the factory 3 1/4" without loosing pressure. There will be hundreds of bigblock owners out there that needed to change to an electric pump because they were using too much fuel for the mechanical pump when they only really needed a full stroke of their mechanical pump.

Re: Wierd fuel pressure problem [Re: nz383man] #709273
05/30/10 12:22 AM
05/30/10 12:22 AM
Joined: May 2009
Posts: 35
Aurora, CO
Manifold Offline
member
Manifold  Offline
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Joined: May 2009
Posts: 35
Aurora, CO
Figured out today why the "genius" who had my car before me put on a crappy auto parts chain store Purolator electric fuel pump vice using the mechanical still bolted to the motor - push rod wore out. After figuring out the new Carter I put on wasn't moving any fuel, I removed it and pulled the pushrod. It measured only 2 7/8" long.

Guess I best track down an OEM so I don't have to go through this again! I really appreciate all the good advice and information folks take the time to post. Thank you!

Re: Wierd fuel pressure problem [Re: 540DUSTER] #709274
05/30/10 10:18 AM
05/30/10 10:18 AM
Joined: Jan 2003
Posts: 21,064
Niles , Ohio
T
therocks Offline OP
oh wait.but hey.lets see.oh yeah.
therocks  Offline OP
oh wait.but hey.lets see.oh yeah.
T

Joined: Jan 2003
Posts: 21,064
Niles , Ohio
Found my old rod.It was a tad longer than the one I took out.Tried the Holley and Carter pumps and still only 4 PSI.I think maybe the cam eccentric might be worn.I might pull the Holley off my kis car and try it.One other question.If I have to go electric do you absolutley need a return line?I might get the Summit pump and reg.My Dominator likes a lot of fuel.Rocky


Chrysler Firepower
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