low fuel pressure, HELP!!!

[1972BlueC20]

Originally Posted by ssxty8

New gauge? This time try a dry one. Not oil filled.

yeah i was going to try that....they are cheaper anyways!

[Lee H]

[QUOTE=MARKDTN;6958691]Yes, a few inches of rubber line is OK.

Lets slow down and take a big-picture look.

-new engine with Holley carb and Holley mechanical pump (did that come with the engine? What didn't you like about the Holley?)
-changed to Edelbrock carb and Edelbrock mechanical pump
-blocked the return line to the tank
-changed to non-vented fuel cap
-various filters and lines and hoses and routings from pump to carb

QUOTE]

According to a separate post on this same subject, the poster stated he has run rubber hose in place of the hard line from the tank to the fuel pump, that was my reference in post three. That is why he wants to run new fuel line.

[MARKDTN]

Originally Posted by Lee H

...According to a separate post on this same subject, the poster stated he has run rubber hose in place of the hard line from the tank to the fuel pump, that was my reference in post three. That is why he wants to run new fuel line.

Yes, if there is that much rubber line REPLACE IMMEDIATELY!. A few inches or rubber line is OK around a filter and tank to line and line to pump, but the more rubber line the more danger of leaks. Maybe a foot total.

[imjeff]

Gauges are liquid filled to keep the needle from bouncing. The altitude it was filled has absolutely nothing to do with the pressure it reads. The air bubbles, especially when warmed up could be the start of a boil...beginning of vapor lock. Double check the proximity of your fuel line with exhaust and motor.

Jeff

[Scott Liggett]

Fuel pressure gauges under hood are notorius for dropping their readings as they get heated by the engine temp. Even the pricey ones. Many manufacturers of the gauges now say to only use them for setting regulator pressure and testing, then remove them. I have had many on 65 Impala over the years, several pumps, regulators, etc; every one dropped to near zero on hot days. Not once 18 years has it ever ran out of gas at 6000 rpm WOT. Gauge readings are not always gospel for accuracy.

[ssxty8]

Originally Posted by Scott Liggett

Fuel pressure gauges under hood are notorius for dropping their readings as they get heated by the engine temp. Even the pricey ones. Many manufacturers of the gauges now say to only use them for setting regulator pressure and testing, then remove them. I have had many on 65 Impala over the years, several pumps, regulators, etc; every one dropped to near zero on hot days. Not once 18 years has it ever ran out of gas at 6000 rpm WOT. Gauge readings are not always gospel for accuracy.

"DITTO"
The one in my 68 Camaro indicates close to real pressure, after bleeding the pressure inside it tho.

[1972BlueC20]

UPDATE!


So I changed out my under hood fuel gauge with a dry gauge (my other was liquid filled)....and the pressure has stayed a steady 6 PSI even after the truck ran for 20 minutes.....previously the pressure would show 2.5 - 3 PSI after the truck ran that long. This is the first time the pressure has stayed steady. I've only ran it once, but it looks like I didn't really have a pressure issue afterall.

I guess it was just a faulty gauge.

I'm not sure if I still have bubbles in the lines since I've put a solid non see through metal filter on, but if it's running good then I don't care I guess LOL

Only problem left is to figure out how to get my TH350 kickdown working correctly....

Thx guys for all your help!!

[ssxty8]

Glad you solved it.

[slomotion]

Originally Posted by ssxty8

Glad you solved it.

What he said

[E.TexasTwister]

I was doing a search of the same type problem and Found this thread.
I was having the same problems with low fuel in the filter and what was in there had bubbles.
It had a clear glass MR. Gasket #9706.
After checking all up and down the fuel line three times and putting on a new fuel pump. (I was going to change that anyway it had been on since '99 and the truck only had 18K on the crate motor.) I also changed out the rubber line from the fuel line on the frame to the pump. It felt soft and it had a flat feel to it where it bent back towards the pump. I thought I had it with that.
NO, Still didn't fix it. If anything it was worse. I changed the filter to a clear canister type.
All problems solved!!! No air, plenty of gas and runs better than it has in months.
It must have been a problem that had been steadily developing.
Keep On Truckin'

[1972BlueC20]

Originally Posted by E.TexasTwister

I was doing a search of the same type problem and Found this thread.
I was having the same problems with low fuel in the filter and what was in there had bubbles.
It had a clear glass MR. Gasket #9706.
After checking all up and down the fuel line three times and putting on a new fuel pump. (I was going to change that anyway it had been on since '99 and the truck only had 18K on the crate motor.) I also changed out the rubber line from the fuel line on the frame to the pump. It felt soft and it had a flat feel to it where it bent back towards the pump. I thought I had it with that.
NO, Still didn't fix it. If anything it was worse. I changed the filter to a clear canister type.
All problems solved!!! No air, plenty of gas and runs better than it has in months.
It must have been a problem that had been steadily developing.
Keep On Truckin'

yeah my problem was a bad fuel pressure gauge, it wasn't really low pressure ...was just showing low on the defective gauge.....i also changed my filter to a metal non see through type....not sure if it's still filling up half way or if it has bubbles...but it's running good now....my other hesitation problems were timing and carb related.....truck is running almost perfect now.....running 21 degrees initial timing.....still have an occasional hesitation from cruise....I think i need to play with the squirter size some more and maybe adjust float levels....

[E.TexasTwister]

Mine is a 350 with a mild RV cam. It is now working fine from cruise. That was the only problem I was having before the no fuel with bubbles.