other Hard overnight starting - SOLVED

['76mintgrün'02]

I don't have a check valve, nor do I have this problem.

 

I really really do have this problem in my 72 Suburban though and it is due to 44 year old cloth covered fuel lines, between the tank and pump; about a dozen pieces of it, with the extra emissions lines.  Some of them are on top of the 42 gallon tank, which I will have to remove, to get at them.  In the meantime, I prime the pump with an extra Snapper fuel tank/hose.  Procrastination is silly, but I digress.

 

How are the fuel lines coming off the tank in your trunk?  My car came with the cloth covered originals, so I replaced them... this may have nothing to do with your issue, but it is one thing that comes to mind.  The pump should hold its prime, but if air is able to enter the line, that may be a problem.

 

Have you tried disconnecting the fuel line at the carb and running it into a catch container, to see whether fuel is flowing when you are cranking?  (after it sits overnight)  I like Jimk's practical solution as well.

 

If you are getting fuel, I would wonder about your ignition timing.  My points adjuster is slipping (to be easily corrected in version #2) and it takes more cranks as the dwell creeps up, which affects the timing.  With it set correctly, it fires in one or two cranks.  I am not suggesting that this is your only problem (if it is even a problem at all), but as Ed suggests above, it may be a combination of things.  So... here are a few more to consider, though they may be gibberish.

Tom

[Healey3000]

First off, I wish to thank Ed (Zinz) for his invaluable assistance with my carb rebuild.  Not only did he send me helpful links but he also offered many pearls of wisdom.  Carb is now rebuilt but the long cranking issue was solved, I believe, by the addition of a check valve in the fuel line.

 

A fairly inexpensive aluminum-bodied check valve from Amazon was plumbed between the fuel pump and filter.  Car now fires up almost instantly, even after sitting for a couple of days.

 

Once again, Ed, thanks a ton!!

 

 

Edited August 25, 2016 by Healey3000

[zinz]

Shucks... t'weren't nuthin'.  I am glad we solved the problem!

 

FYI, I ended up putting this inline check valve just out of the tank to keep fuel from draining back through the electric pump.  I now have good fuel pressure at all times, no matter how long it has been sitting.  

 

 

http://www.siliconeintakes.com/liquid-air-adapter/aluminum-one-way-check-valve-8mm-barbed--p-9581.html

 

Ed Z

[dang]

1 hour ago, zinz said:

Shucks... t'weren't nuthin'.  I am glad we solved the problem!

 

FYI, I ended up putting this inline check valve just out of the tank to keep fuel from draining back through the electric pump.  I now have good fuel pressure at all times, no matter how long it has been sitting.  

 

 

http://www.siliconeintakes.com/liquid-air-adapter/aluminum-one-way-check-valve-8mm-barbed--p-9581.html

 

Ed Z

 

Nice.  My 2003 GMC truck has a faulty check-valve on the fuel pump and I have to turn the key about five times each time I start the truck.  I've considered adding another check valve, thanks for the info!

 

[Healey3000]

The one I used looks exactly like the one in Ed's pic above, except that I got it on Amazon Prime (no shipping :-)).

[BarneyT]

I had the same problem for a long time after a drive figured out the tank was under neg. pressure and pulling the gas back to the tank because the air was not replacing the used fuel at an equal rate...

[Guy Cocquyt]

On a related issue, I have an electric pump in the trunk, good fuel pressure and performance, good quick starting, but I am getting vacuum pressure in the tank, after I shut the engine off I have the tank loose the vacuum with a boink sound. Also the gas cap is under vacuum pressureand takes some effort to pull off right after shutting down the engine. Should I be concerned?

Sent from my SM-T110 using Tapatalk

[Simeon]

3 hours ago, Guy Cocquyt said:

On a related issue, I have an electric pump in the trunk, good fuel pressure and performance, good quick starting, but I am getting vacuum pressure in the tank, after I shut the engine off I have the tank loose the vacuum with a boink sound. Also the gas cap is under vacuum pressureand takes some effort to pull off right after shutting down the engine. Should I be concerned?

Sent from my SM-T110 using Tapatalk

 

It definitely means that you don't have a viable breather on your tank. You should be concerned. The tank should be at atmospheric pressure. 

 

Are you you missing the breather pipe plumbed from the tank filler neck at the top to either a hole in the trunk floor or to the engine bay via a charcoal canister?

[Guy Cocquyt]

Thanks Simeon, I thoughtthis was odd. I traced the breather tube in the filler neck to see where it is coming out. A cursory inspection looks like it is going to a plastic tank just above the right strut in the trunk. A second tube into this plastic tank looks like it is going forward through the trunk wall toward the front of the car. Will have to see where that one leads.

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[Simeon]

That one leads to underneath the battery in front where the old emissions system saw the fumes burnt in the engine. It is likely to be plugged at that end. 

[Transcon]

I deal with this daily on the first start after an overnight/multi-day sit. Feeding dual DCOE 45's I have just come up with letting the pump run for around 20 seconds as I am getting sorted in the car, 2 long pumps on the pedal and another 10 seconds....starts right up. After the first start of the day it never seems to have a problem again until it sits for more than 8-10 hours

[zinz]

Spend the $8 on the check valve, install it close to the gas tank.  I bet you won't have this long wait time to pressurize the fuel system.  

 

Ed