It stalled and I'm a bit confused

fyton2v

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Drove the truck about 100 miles today. Ran fine on the way to work this morning (50 miles). Ran fine almost all the way home ... up to about 45 miles. So close. In general, it idles and accelerates fine. Vacuum is around 17 - 18 at idle. Starts right up. I'm pretty happy with it. But tonight, just as I came to a stop at a light, the idle started to drop and it seemed like it wasn't getting fuel. Then it stalled out. It cranked fine, but it wouldn't even try to start. No fuel, right? Fortunately for me, it stalled right next to a gas station and random nice dude helped me push it into a parking spot.

Tried cranking it over a bit more and nada. I opened the fuel cap to equalize the pressure because maybe somehow that could help. Had no idea. There was less of a woosh than it usually does when the cap comes off (I think) but I haven't been paying much attention to the vacuum in the tank. Put the cap back on, put the choke on, and cranked it again. After maybe 7ish turns it started.

So ... no fuel, and then it gets fuel. What could cause that? The fuel pump is new. The fuel filter is new. I haven't started really troubleshooting yet, that'll be a tomorrow thing. Just wondering where a better mechanic would start first.

Thx.
 

graham5david

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Vapor locked?
I'm not sure what your set up is but you could have a line getting hot and making excess vapor. If you have an original tank you could have a hole in the pick up tube. Could be fuel pump related. Hard to say without more details on your overall set up.
 

ToyotaMatt

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brian

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The "whoshing"...of any amount, is a bad thing...it means the tank is operating either at pressure or under vacuum....neither are good for fuel delivery.
 

hobbes

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How old is the fuel tank? What kind of carb? Does it have a fuel return?
 
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What year cruiser? Early years fuel tank was vented. Those the tank will go into a vacuum with the proper vent. Long trip at higher fuel consumption would where this would most likely show up.
 

fyton2v

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78 and all stock as far as the motor and related things go. Stock Aisin carb that was recently rebuilt, but by me, not a carb guru. Seems to work fine. It has fuel return. The tank is original.

I guess the reason I focused on the tank is because I think everything from the fuel filter to the carb is prabably good. I don’t understand the fuel return and vacuum in the tank parts. As I think about this, the less gas in the tank, the bigger the wooosh. In this case it was prob about half full.
 
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The "whoshing"...of any amount, is a bad thing...it means the tank is operating either at pressure or under vacuum....neither are good for fuel delivery.
This. If your tank isn't properly vented it can create a vacuum that your mechanical fuel pump can't overcome. Open the cap, the vacuum is released and the pump is able to pull again. I would Find a sacrificial cap and put a baby sized hole in it/remove the rubber seal and run it that way long enough to see if the problem goes away...then search for the root of your non venting tank.(assuming it runs out with a vented cap)
 

pb4ugo

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What is the condition of the tank? Is it rusty inside? You said you weren't concerned from the filter to the carb, becuase its recently been cleaned. Could the filter be clogged? I'm not that familiar with 2f's carbs, but my understanding they have a float bowl window. Is there fuel in the window? If your cranking for a while with the choke closed to gettit to fire, you are either trying to suck fuel thru the carb or you could have significant vacuum leak.
 

fyton2v

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I can’t know for certain if the tank is fine and there is zero gunk in there. But it’s probably OK. I had it out of the truck around 6 years ago and it looked good then. I live in a dry climate.

I’ve been restoring this thing for about 20 years (I work very slow, but at least the quality of my work is mediocre). Because it was always in some partially unfinished state I kept my rides local. Now that I think about it, my longest trips were mostly getting it warmed up and ready for a smog test. After doing a bunch of part replacing recently it now runs better than ever. And this was my longest trip in the most recent version of the truck. Just about 50 miles at freeway speeds, 2 ways about 8 hours apart.
 

fyton2v

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I checked the evap lines from the fuel tank and they seem clear. While inspecting the charcoal canister lines, I noticed that the connection to the VCV came off. Unsure if that’ll cause the unplanned shutdown or not. I need to learn more about what that doodad does and when it’s supposed to do it’s thing.
 
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Maybe your idle selenoid or the wire powering the selenoid is bad? Does is start up when pumping and holding the gas pedal down?
 

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