1983 Big Block Monte Slow Build (Lowered Expectations)

[Supercharged111]

Weird, when I looked up M4514 it came back as a late 69s big block pump. I thought 30gph was good for more than what I'm making? But if MKIV spec'd a 40gph I can pursue that.

As for the suction side, rher'd only be a small section in question as a majority of the mid section hard line has been replaced. Wouldn't a guy have a leak if that were to blame? I can say for sure it's not the cause of the car not running, but may still rear its head with a good pump if that's to blame. The tank and sock are pristine, they were out back in December and thinking back, this problem predates that by quite a bit. I seem to recall my dad lamenting the thing running out of fuel back around 2018, I believe he got there because he had the vacuum modulator cranked to the moon and back. I had to fiddle with the governor to get it to wind up hard enough for that.

 

[scoti]

Weird, when I looked up M4514 it came back as a late 69s big block pump. I thought 30gph was good for more than what I'm making? But if MKIV spec'd a 40gph I can pursue that.

As for the suction side, rher'd only be a small section in question as a majority of the mid section hard line has been replaced. Wouldn't a guy have a leak if that were to blame? I can say for sure it's not the cause of the car not running, but may still rear its head with a good pump if that's to blame.

Mine didn't leak. I was having issues starting though. My engine is also a stock 305/2barrel carb so there was rarely a time when fuel demand while running was an issue. I could see leaks being very noticeable on the pressure side under the same circumstances (cracked lines) vs the suction side.

I actually had a similar issue on my dually more recently. It was fine @ idle & low load/rpm. Once over 2k rpm or more of a load (going up a steep hill) it struggled severely. I had replaced the fuel pump & the flex lines from the frame to the pump assembly fittings a week or so prior. I requested FI rated line but the counter guy gave me low pressure rated line & it kinked/collapsed on itself after a few days once fuel went through it. I had to drop the tank again & put the stiffer hi-psi FI rated hose (I also used longer lengths so it could be looped vs a sharp bend). Fuel starvation issue resolved.

 

[Supercharged111]

M4514 is just a base Chevy 305/350/400, 8 psi, 30 GPH.

M16011 converts to MF0001, Mark IV 454, 7 psi, 40 GPH.

I had lots of problems with O'Reilly's pumps, but on the 3 port units, not on the simple in/out ported units.

NAPA quality usually a little better, but as they say..., You get what you pay for.

If problem persists, check for plugged up sock or line with partial obstruction, or rotted out line sucking air.

I just called Napa and they said the M16011 is 23gph and M4514 is 30gph.

Edit: the plot thickens! The Carter version is 23gph and the Delphi that arrives this afternoon is a 40gph unit. At least according to Napa's books.

 

[Supercharged111]

Mine didn't leak. I was having issues starting though. My engine is also a stock 305/2barrel carb so there was rarely a time when fuel demand while running was an issue. I could see leaks being very noticeable on the pressure side under the same circumstances (cracked lines) vs the suction side.

I actually had a similar issue on my dually more recently. It was fine @ idle & low load/rpm. Once over 2k rpm or more of a load (going up a steep hill) it struggled severely. I had replaced the fuel pump & the flex lines from the frame to the pump assembly fittings a week or so prior. I requested FI rated line but the counter guy gave me low pressure rated line & it kinked/collapsed on itself after a few days once fuel went through it. I had to drop the tank again & put the stiffer hi-psi FI rated hose (I also used longer lengths so it could be looped vs a sharp bend). Fuel starvation issue resolved.

If this bigger pump doesn't do it I'll turn a more discerning eye to the aft section of line. That's really all that's left. But good to know it was sucking low pressure line shut! All the rubber up front is Gates high pressure stuff.

 

[scoti]

If this bigger pump doesn't do it I'll turn a more discerning eye to the aft section of line. That's really all that's left. But good to know it was sucking low pressure line shut! All the rubber up front is Gates high pressure stuff.

Yeppers.... I requested the hi-psi stuff & questioned what he was handing over to me as it was too soft from my observation & previous experience w/that spec type of hose. But he & my car buddy that was w/me said it was hi-psi which made me defer. It wasn't hi-psi stuff (look for the green stripe/writing on the hose if it's Gates). Night & day diff as far as the feel & qty of cording within the rubber.

 

[78Delta88]

I just called Napa and they said the M16011 is 23gph and M4514 is 30gph.

Edit: the plot thickens! The Carter version is 23gph and the Delphi that arrives this afternoon is a 40gph unit. At least according to Napa's books.

Hmmm yes the plot thickens... Better get Matlock or Columbo on it.

 

[78Delta88]

I used to go to the IAAI insurance auctions for builders and parts cars. Saw several 80s era burnt to the ground. The older fuel lines can not handle today's fuel. They get dissolved from inside out. Something many today don't think about.

 

[78Delta88]

On the fuel pumps, I used to get the 3 port units from O'Reilly's that match the OEM. The third connection was a return for the internal pressure regulator. Instead these were just pumping fuel back to the tank and not to the carb. Turned all of them back in and only use the simple 2 port units... Fuel in ---> Fuel out. Problem solved.

Also need to know... Many of the countermen today don't know the difference between vacuum line, fuel line or 3/8 radiator overflow line. So you got to watch...

 

[Supercharged111]

That may well be why the stuff I replaced was a bit mushy on the inside.

 

[78Delta88]

That may well be why the stuff I replaced was a bit mushy on the inside.

Could be.