Fuel Delivery issues

[Gussy]

I have a 1980 Datsun 210 that starves for gas going up inclines. Shuts down and when looking in the engine bay even the fuel filter is empty (no fuel in it). I read that this could be related to lines being blocked but after looking over the fuel lines I noticed a connection at the fuel tank that has been blocked off with a piece of hose and clamped. Could this issue be the tank not venting properly? I don't have a diagram of the fuel/vent lines so kinda sketchy for me. Any help would be great.

[Bleach]

I had a similar issue with a 620 truck. It was a partially clogged fuel line. I disconnected both feed and return lines and blew compressed air through the line both directions. Rust came out.

 

After that, I ran a new filter and saw a lot of rust from the tank coming through for a while. I changed the fuel filter at every oil change. Worked perfect from that point on.

 

If you have an aftermarket carb and only run the feed line, you may want to try running a return line so that you are circulating your fuel from the tank at all times. That will help to make the best use out of that filter and get those rust particles trapped.

[banzai510(hainz)]

3 hours ago, Gussy said:

Could this issue be the tank not venting properly? I

did this work before??????????? then it should work now.

But can alwaysy take the cap off and see say run it at half tank.

 

Mos time its a fuel filter or maybe by chance the float is running dry on a incline. (rule this out as last) as I hate takinf a carb apart to find nothing wrong with it. a Stock carb is a Rubix cube. I cant do myself a Weber DGV is alot ezer

[wayno]

I echo Hainz, try taking your gas cap off and going up the same hill the same way, if it starves then it is not a tank vent issue.

[datzenmike]

 

 

 

Said it does it on inclines where the demand for fuel is higher than normal. You would have to almost empty the tank for the pump to not be able to suck fuel out of it against the vacuum. This is part plugged line, dirty filter or filter on the carburetor inlet banjo fitting, or the float is set too low.

 

The breather and the fuel line are both mounted higher on the tank. The return line lower down.

 

If there is a clamped hose look around for the hard line it was connected to.

 

 

Look at the front of the carburetor, it should have a small sight glass showing the fuel level. Normally it will be in the middle. If low then the float is set to low and needs adjusting. If normal then it's a delivery to the carburetor problem.

[junkafide]

Try going up the same hill in reverse, that will tell you if the gravity is helping the pump along. 

[ggzilla]

Yes, it could also be the float level. If set low, the engine can still run, but when the engine is working harder, requiring more flow it could starve. Itis SO EASY TO CHECK that I always start with this visual inspection:

 

 

If the fuel level is within 1mm of the dot, it is already at the correct adjustment

 

This one is too low

 

 

AAAND it may still have an original sintered brass filter in the carburetor inlet. That works just like a fuel filter and over the decades can plug up. Just remove it, and change the regular fuel filter once a year

 

 

the vent line is crucial, not sure if it would cause a problem solely on inclines, but it can starve the engine after running long enough to evacuate the tank of air. USA fuel tanks since at least 1971 were not vented at the cap, but only through the vent line up to carbon canister which is in the engine compartment

1980 B310 (210) canister

 

[datzenmike]

The cap is sealed to keep hydrocarbons from getting out. As fuel is used up air is equalized by the vent line and the vent line is connected to the charcoal canister that stores the fumes. I had a 16 gallon 720 tank on my 620 and something was wrong with the vent and the tank imploded.

[ggzilla]

Thanks, that reminds me. The fuel cap is supposed to have a vacuum relief. So hydrocarbons can't get out, but if the tank is subject to vacuum, it lets air in. If someone has replaced the cap with a solid one, the tank can implode, or the engine stall. Ive seen this more than once

 

Bottom line: check the cap to make sure

It should be more or less flat on the outside, with a nubbin on the inside

 

Testing

• You should not be able to blow air out throw the cap
• You should be able to suck air in through the nubbin

1. Wipe valve housing clean and place it in your mouth.
2. Inhale air. A slight resistance indicates that the valve is in good mechanical condition. Note that, by further inhaling air, the resistance should disappear as the valve clicks.
3. If valve is clogged, or if no resistance is felt, replace cap as an assembled unit.

[Gussy]

@datzenmike has to be delivery to carb in my case because the fuel level in the sight glass is right in the dot until it shuts down on inclines. I wanna rule out the lobe on the cam that operates the fuel pump is worn since the car only has 48k original miles on it. I did blow out the lines and I'm getting some gunk coming to the filter so I'm gonna change filter out and see how the car operates. As far as the clamped line, I cannot find a hard line where it would connect to. I'll keep you guys posted on results. Appreciate all the feeback.

[banzai510(hainz)]

needle valve sticking ???????????letting gas in

 

make sure your in time with your distributor. open it up and ck the vaccum adv is not loose you your timing is set right

[datzenmike]

Most common cause is a partly restricted fuel filter but you said it's ok. Maybe not visible. They're cheap so just replace, probably due anyway. 

 

 

Pull the hose off the carburetor or connect a hose to the pump outlet and direct into a suitable container far enough away from the engine. Turn the warm engine on and let idle. You should be capable of about one liter in one minute or less. Get help doing this.

[Gussy]

Changed the filter out and I believe that was the issue considering now I'm getting too much fuel to the carb. The fuel level on the sight glass is high.

[datzenmike]

Results are all that count. Does it climb hills now.

[Gussy]

@datzenmike you're absolutely right! I'm waiting for it to warm up and taking it for a ride

[Gussy]

@datzenmike so I drove the car for about 15 minutes. Went up an incline about a 1/4 mile long and no hesitation or stalling. After I got back I checked the level in the carb and it looks almost spot on now. Appreciate the help! Once the weather gets nicer out I'll be going for a decent ride. Thanks again