I have an electric pump (in the tank) and I have a carb which needs about 6.5 psi. I installed a regulator but the most pressure I'm getting is 5.5 psi. the regulator adjusting screw is in as far as it will go. Any thoughts on what to look for or any other options.

This is an '82 with a ZZ4 engine with a Holley 770, (no mechanical pump)

Thanks,

Dave

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Lifetime Member #116
Dave's '82

   

Is there any way to get a pressure reading with no regulator in line? Maybe the pump isn't putting out to it's fullest potential.

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GEN III 5.7L "LS6" Engine swap
TKO500 5 spd.

The car runs. I'd have to disassemble the regulator and get a  fitting to go from the AN-8 to a 1/8NPT to mount a gage. Would be a pain in the a__. I don't see that pump going from 55psi(stock) down to 5psi. When I can get to the underside I'm going to change out the filter, maybe that will help?

Dave

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Lifetime Member #116
Dave's '82

   

Dave, I know you did your engine upgrade quite some time back, did you change the pump at the same time?  The pump itself may indeed be your problem or if not replaced when you did the engine upgrade, the short hose section between the pump and output hard lines going to the engine.  If you still have the frame  rail mounted fuel filter, it may be worth a swap if its been a while since it was changed.

Update:You must have posted while I was typing.  From your reference to 55 psi you must have installed a C4 pump previously, probably when you were still running crossfire.  Id check the filter.

|UPDATED|2/9/2015 6:03:08 PM (AZT)|/UPDATED|

Hey Chip how are you? Yes I have the '85 pump in there. I have to wait for a little warmth, since I have to move the car outside to get under it to change the filter.

Thanks,

Dave

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Lifetime Member #116
Dave's '82

   

Change the filter first, certainly.
I would try to find a way to test the fuel pressure before the reg. at the same time, if possible. As was mentioned, the rubber-like hose on the fuel pump can split/crack, and cause a severe loss of pressure and volume, as could a collapsed "sock" filter on the end of the pick-up tube on the sender unit.
Also, a loose/corroded connection can lower the working voltage available at the pump, and slow it down.
Hope a filter takes care of it, tho.

One way to kinda-sorta test for a cracked rubber hose on the pump unit is to fill the tank full. When full, the hose will be covered, so the crack/split would be moot. If the pressure at your gauge goes up with a full tank, then that points to the rubber hose being bad.


|UPDATED|2/10/2015 11:34:23 AM (AZT)|/UPDATED|


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Joel Adams
C3VR Lifetime Member #56    
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"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

Thanks for asking Dave.  Im doing well, just dont bet by the forum as often as I used to.  Still have my 82 and she is running fine.   Hope all my old friends here are doing well.  Ill try to poke my head in a little more often.

Well it looks like I'll have to wait awhile for the weather to get better so I can change the fuel filter. I could put a gage on the rubber hose at the filter when I take off the old one. Can't get out to fill the tank because of snow & salt. I'll keep you up to date.

Thanks guys!

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Lifetime Member #116
Dave's '82

   

So I changed the fuel filter and set up the carb and all is well, timing is perfect, 15lbs. of vac, mixture right, and idle is set.  We are good to go!!!!!!!!

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Lifetime Member #116
Dave's '82

   

  

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Joel Adams
C3VR Lifetime Member #56    
My Link


(click for Texas-sized view!)             NCRS

"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

    Hoorah!   Now we can travel.

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Now I need to put new seals in my rear end (the car's that is).

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Lifetime Member #116
Dave's '82

   

We've been around you Dave, you might want to do both.

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Dave C..........My mantra: I can not be bought!!      Long and short term leases available.

Turns out the fuel pressure is still at 2psi, so I pulled the fuel pump out of the tank and found that the short hose from the pump to the steel line is split open. I got a new pump with all the new parts to go with it and put it all back together and now I have my 6-7 psi at the carb. Glad I got that done before the gathering, if the hose let loose altogether I would have NO fuel at the carb, not a good thing.

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Lifetime Member #116
Dave's '82