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Discussion Starter · #1 ·
I'm looking for some insight as to a summer problem, It's 107 out and the road is hotter, I have a 64 Chevy van with a basically stock 350, I even had to some extent the problem with the original 6 cyl. so I'm thinking it's more of a formulation of the fuel issue. The engine temp is below 200 usually 190, I had the tank cleaned and sealed and removed it yesterday just to make sure all was fine there and it was,There is no filter on the fuel pick up tube. I have a fuel pressure guage at the carb and a glass filter by the fuel pump. I had an Edelbrock fuel pump and changed back to a stock one just as a test to eliminate that as the cause. As long as it's below 100 out it runs pretty well, If you are cruising along all is good if you stop at a light you can feel something isn't happy. This weekend I was really trying to see what's going on and now I'm needing some thoughts. At the light or after you get on it for a bit and then slow down you can watch the fuel filter level start to drop and then fill with bubbles and the fuel pressure drops to 0 and doesn't come back up to the 4-5 range unless you shut it down and sit for 20 min. or so you're lucky if you can get it up to 15mph. I did change the pump again yesterday and removed the inline filter even removed the gas cap to see if that or any was the cause, I have new metal fuel lines run throughout, to me it seems that the fuel is already hot in the tank and the road mades it hotter, and then the fuel pump just agitates an already volitile liquid and then starts cavitating. I'm thinking an inline fuel pump might do the trick or keeping the stock pump and running a return line back to the tank so it's not dead heading at an idle and would always have fuel flow. Any thoughts would be appreciated. Thanks, Eric
 

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FWIW,
The only time I ever saw air bubbles in a see thru filter (after the pump) there was a crack in the rubber hose between the tank and the hard line on the frame.
I don't suppose you could remove the line right where it exits the tank, and just before the pump, plug the pump end of the line with an air gauge, and hook up a high pressure air source to the tank end of the line with a valve that you could shut off after pressure builds in the line and monitor the leak down or see if it will hold pressure.
Just a thought, FWIW
ssmonty
 

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On second thought, instead of using air pressure, connect a vacuum pump at the line coming from the tank, and a plug at the pump end of the line. See if it will hold a vacuum?
Maybe a piece of trash is blocking the line. Might try blowing compressed air into the line at the pump end(line disconnected at the tank) to remove anything that might have got into it from the tank end.
FWIW
ssmonty
 

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Discussion Starter · #4 ·
Thanks for the thoughts, I have a pretty good vacuum pump and I'll see if that will work, The more I think about it maybe with everything being that hot (temp,road heat) maybe one of rubber lines is collapsing? There is only 3 places where there is rubber and it's only about 5-6" long but I'll pick up some industrial tubing at one of the jobbers just to eliminate that, It runs so well when it's cooler out and I don't see anything that obvious. Thanks again for the thoughts, Taking thursday and friday off so maybe I'll drain and pull the tank again and replace the rubber hose there and through the rest.
 
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