Fuel pressure

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kma176
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Fuel pressure

Post by kma176 »

My Satellite with a 419 stroker - running a Manual high performance Edelbrock pump & 750 double pumper dead headed .
From cold I'm getting just over 7psi but as it warms up it drops to 3 to 3.5psi .I didn't think I should be getting any drop as it warms up ???
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Pete
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Re: Fuel pressure

Post by Pete »

No, there should be virtually no change in fuel pressure if a regulator is used.

Check the Float bowls again and see if the carb is flooding down the venturi when the pump is on...
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kma176
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Re: Fuel pressure

Post by kma176 »

Yeah thanks for the reply Pete I'm using a Manual pump so obviously can't turn on .It seems to run perfectly fine stationary but haven't driven it on the road as yet.(Theres no flooding and doesn't seem to bleed fuel)
This reading was taken with the fuel line dead headed - when I re-connect the pressure reg and return line the pressure is less but still gets lower as the engine warms up?
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Pete
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Re: Fuel pressure

Post by Pete »

Most Manual pumps are self regulating to about 5 - 6 lbs so should not be an issue or require a separate regulator, though the big Carters may give pressure spikes... The only other thing to check is whether the pump push rod has worn down...
Pete Wiseman; Cambridge.

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kma176
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Re: Fuel pressure

Post by kma176 »

Pete wrote: Sun Oct 13, 19 9:18 pm Most Manual pumps are self regulating to about 5 - 6 lbs so should not be an issue or require a separate regulator, though the big Carters may give pressure spikes... The only other thing to check is whether the pump push rod has worn down...
I have checked the pump all in good condition operating arm is fine - the problem I'm concerned with is the pressure drop as it warms up - why would it drop???
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Pete
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Re: Fuel pressure

Post by Pete »

I see in the pictures in your other thread (great by the way!!) that the pump seems to be a copy of the big Carters, like I would run on a 440.

You can actually take flow measurements with the pump off the engine but it is hard work.

I do not see why the pressure would drop - it may be Ok if the flow is good and constant.

It may be worth putting a plastic (not glass) fuel filter in line and observe what happens...
Pete Wiseman; Cambridge.

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kma176
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Re: Fuel pressure

Post by kma176 »

Pete wrote: Sun Oct 13, 19 10:38 pm I see in the pictures in your other thread (great by the way!!) that the pump seems to be a copy of the big Carters, like I would run on a 440.

You can actually take flow measurements with the pump off the engine but it is hard work.

I do not see why the pressure would drop - it may be Ok if the flow is good and constant.

It may be worth putting a plastic (not glass) fuel filter in line and observe what happens...
I'm running two filters one inline between tank and pump and a glass filter(that is out of harms way!)between pump and carb - I will observe that a bit closer tomorrow- the pump is Edelbrock 1720 I have stripped it and all looks good inside no diaphragm split and the valves all seem to work and no debris.
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kma176
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Re: Fuel pressure

Post by kma176 »

I have eventually had a reply back from Holley - They tell me they don't make a pressure regulator with a return to tank for a manual pump and the pressure drop could be down to me purchasing the better fuel pressure gauge that is oil filled he reckons as it warms up they can give an unreliable reading ????
If its the case that the pressure reg is incorrect - any thoughts on the best way to run a fuel return with a manual pump set-up??
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Re: Fuel pressure

Post by Derek »

Kev, do you really need a fuel pressure guage.
Are we there yet dad ..... 10 to the gallon but worth it.

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Prothed
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Re: Fuel pressure

Post by Prothed »

No idea if this relates to your specific problem, but this post shows how a 'vapor separator' and return line are set up...

https://www.forbbodiesonly.com/moparfor ... ak.148543/
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kma176
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Re: Fuel pressure

Post by kma176 »

Derek wrote: Sun Oct 20, 19 5:37 pm Kev, do you really need a fuel pressure guage.
No probably not - just thought dotting the eyes and crossing the T's while I'm there - but now its there why does it drop so much ?? If I hadn't of fitted it I wouldn't have known and it would probably be fine and will drive OK( But its there now why, why :angryfire: :angryfire:
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kma176
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Re: Fuel pressure

Post by kma176 »

Prothed wrote: Sun Oct 20, 19 5:50 pm No idea if this relates to your specific problem, but this post shows how a 'vapor separator' and return line are set up...

https://www.forbbodiesonly.com/moparfor ... ak.148543/
I Haven't got a problem so far as I know(not on the road yet) Just thought it would be good to run a return line while doing the plumbing !!! :dontknow:
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Blue
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Re: Fuel pressure

Post by Blue »

I use a carter mechanical pump with a deadheaded holley regulator set at 5psi on the Barracuda. At times the pressure might go up to 9 or it might drop to 3, you adjust and its fine until the next time. I've had holley regs on many cars over the years and in my experience this is typical behavior, it's what they do. I have had 2 cars with return lines and non holley regs, both worked at the set pressures all the time with no issues. I'm not a fan of deadheaded fuel systems, you might want to look into a return line, I think you can get a fuel filter with 3 nipples on it to make it easier to plumb.
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kma176
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Re: Fuel pressure

Post by kma176 »

Blue wrote: Mon Oct 21, 19 7:09 am I use a carter mechanical pump with a deadheaded holley regulator set at 5psi on the Barracuda. At times the pressure might go up to 9 or it might drop to 3, you adjust and its fine until the next time. I've had holley regs on many cars over the years and in my experience this is typical behavior, it's what they do. I have had 2 cars with return lines and non holley regs, both worked at the set pressures all the time with no issues. I'm not a fan of deadheaded fuel systems, you might want to look into a return line, I think you can get a fuel filter with 3 nipples on it to make it easier to plumb.
Not sure if you remember but I posed the question sometime ago and you gave me the idea for the set-up with the Regulator being after the fuel log and then with a return to tank using a bypass regulator - well that's how I've set it up .
So I'm probably worrying about nothing with the pressure drop!
The so called technical expert at Holley I think is talking out of his backside - the oil filled gauges I thought were just to dampen the flicking of the gauge - so far as I know it will not affect the pressure reading ! But he also tells me they don't make a regulator for manual pump that runs a return?
The one I fitted seems to be working OK !
Were the 2 you had with return lines running manual pumps or electric?
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Blue
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Re: Fuel pressure

Post by Blue »

Both return line systems used electric pumps, One using a regulator on the return and the other using a regulator with a return port. I agree, I'm not buying the liqiud filled gauge thoery either.
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