1
Fuel Systems and Drivability / Re: Fuel System Picking up Air
« Last post by prider5 on Today at 06:01:43 pm »Thanks for letting me know bd! I can make a new thread if you'd like.
Truck is 1977 K20, with a lot of parts from a 1980 K10. 350 SBC with a 1906 carb, and has dual tanks.
I've been rebuilding the truck, so it currently has 2 new fuel senders (dorman iirc), new tank switching valve, and just recently put a new mechanical fuel pump on (after having fuel delivery issues). I thought maybe the hard line had a hole somewhere, so I recently ran new rubber line from the switching valve up to the engine and made sure I ran it away from heat (thought it was potentially vapor locking), and back when I put the sending units in I ran new rubber lines before the valve as well.
I have a clear filter after the fuel pump before the carb, and I can see it pump fuel well when I first start it, and then after 10 minutes or so of driving the filter runs dry, with what looks like a lot of air bubbles flowing in as it runs out. Been struggling to figure out what the issue is, contemplating just putting an electric pump on it, but it would probably need to be after the switching valve, and I know they are notorious for not wanting to pull fuel and going out, so not sure. I think I tried it without the cap on as Vile suggested, but it's been a bit now and I'm struggling to remember for sure ha. I'll try this weekend if I can find the time to go and test.
Truck is 1977 K20, with a lot of parts from a 1980 K10. 350 SBC with a 1906 carb, and has dual tanks.
I've been rebuilding the truck, so it currently has 2 new fuel senders (dorman iirc), new tank switching valve, and just recently put a new mechanical fuel pump on (after having fuel delivery issues). I thought maybe the hard line had a hole somewhere, so I recently ran new rubber line from the switching valve up to the engine and made sure I ran it away from heat (thought it was potentially vapor locking), and back when I put the sending units in I ran new rubber lines before the valve as well.
I have a clear filter after the fuel pump before the carb, and I can see it pump fuel well when I first start it, and then after 10 minutes or so of driving the filter runs dry, with what looks like a lot of air bubbles flowing in as it runs out. Been struggling to figure out what the issue is, contemplating just putting an electric pump on it, but it would probably need to be after the switching valve, and I know they are notorious for not wanting to pull fuel and going out, so not sure. I think I tried it without the cap on as Vile suggested, but it's been a bit now and I'm struggling to remember for sure ha. I'll try this weekend if I can find the time to go and test.

1
Recent Posts
