78 wont start after *nearly* running out of gas

[~rick~]

Hey there guys, I'm new to the forum. I bought a 78 620 longbed a couple of months ago and I've been learning alot about cars along the way, often with advice from here.

Last week, I almost ran out of gas. I barely limped into a gas station with the truck losing power. After I put a couple gallons in, she wouldnt start.

I've replaced the fuel pump (electric because it has the a/c), assuming that the strain of that last block to the gas station was too much for it to bear. Still nothing. I've got a brand new battery, coil, plugs, wires, cap, and rotor, so I'm pretty certain I have spark. I pulled the fuel hose to the carb, the stock hitachi, and confirmed that I have fuel coming to the carb. I dont know how it is supposed to be, but the float window is never full or empty; it fluctuates slightly around the middle. I know you all hate the stock carb but I aint gonna have the dough for a weber for a little bit, so,no, I can't just ditch the hitachi.

Any help would be appreciated, I'm runnin out of ideas haha

[Draker]

First pull a spark plug wire and confirm you have spark.

 

Second, If you ran the tank super low.. the pickup tube probably sucked in all sorts of debris. But it sounds like you have fuel to the carb. The fuel level should be right around the middle of the sight glass.

 

Does it sputter and not start? Or does it just not start at all?

[banzai510(hainz)]

Did you see spark?  Not pretty certain shit.

Yes or no.

If you have spark

 then do you have gas in the carb. sounds like yes. so cycle the carb so gas squirts in the carb from the accel pump. then it should start if the all the valves are closing normally.

 

olddatsuns.com read the datsuns tech section.

 

 

why you replaced the fuel pump again? it works or it dont.

[~rick~]

I say pretty sure because I can see the engine shaking when I try to start it. I dont have anyone to turn the key for me while I see if it has spark, so I guess I can try to catch someone walking by or something haha.

I replaced the fuel pump because it was cheap to do, and I figured it to be the most likely cause of my troubles. I assumed it had sucked up something from the bottom of the tank and wasn't operating at the proper capacity.

When I try to start it, it doesn't even sputter, it just turns the engine over.

[Lockleaf]

If necessary buy one of these.

 

 

Called a remote starter switch, it allows you to run the starter from under the hood. They are cheap and can be found at auto zone, oreilly, harbor freight etc.

[racerx]

You can ground spark plug to valve cover (better to do this in the garage so you can see the spark better) or buy a spark tester at Harbor freight for like 5 bucks to make sure you have spark.  Just because a car engine shakes it does not mean you have spark. There's also a guy here selling a slightly use 32/36 weber for like $150.  So check if you have spark first and how good is the spark. You can also disconnect fuel line going to carb to see if you have gas coming out or open the throttle all the way and look inside your carb to see if it's squirting fuel and nothing wrong with stock carb as long as it works. Good luck!

[banzai510(hainz)]

2 things you say. shutter then at the end doesnt even sputter so I am confused.

 

Iam not 620 qualified but with my 521 the key is on the left side and I can reach in and turn the3 key and hold the coil wire to ground and see if sparks.

 

if elelctric fuel pump its cheaper to pull the output hose and turn the key On and see if it squirts gas!!!!!!!!!than buy another fuel pump. Is it the correct pump and correct fuel pressure for that rig??????????

 

 

1 recheak for spark

2 see if gass shots in carb when cycle linkage.

 

anwser those 2 questions first

 

 

it should still fire off if you have spark and pour soem gas in the carb but this is same as cycleing the linkage. the fumes will light off if you have spark.

 

OK awser the ?s 

[datzenmike]

Almost running out of gas is not going to affect the spark. There's no reason to suspect that the spoark or ignition system has been affected. How could it???

 

Almost out of gas sounds like a possible fuel problem to me. As the fuel pick up is at a set distance from the bottom of the tank it's unlikely water would be sucked up when low if it wasn't when full. Low fuel will stir up sediment but you have a '78 with a return line so there won't be much crap in the tank. Sediment will never get to the fuel pump because it's the job of the fuel filter to catch it.

 

Look at the front of the carb... is there gas showing in the window???

 

 

Maybe that new pump does not work and why stuff should never be blindly replaced. Put the old pump back on and remove the output hose and direct into a suitable pail. Have someone crank engine. Fuel should shoot out in strong squirts.

 

If not maybe the filter is clogged?

 

 

 

Some systems have a hard time priming when only cranking the engine. Dribble some gas directly into the carb and fire up briefly. This will suck it through... but check that filter.

[datsun 160J SSS]

CHANGE the gas filter