Need help,, what do you suggest ?

Discussion in 'General Chevy & GM Tech Questions' started by Rat Rod Mac, Jan 7, 2014.

  1. Rat Rod Mac

    Rat Rod Mac New Member

    First off, new here, but I am searching the net for a place to ask a question and maybe some good advise and suggestions.
    I have a 1982 Chevy 1/2 ton pickup, standard cab, 8' bed, two wheel drive with an auto tranny and a 1977 350 small block in it. It's old with quite a few miles on it, but I want to get a year or two out of it. It never did get real good gas mileage, but in the last couple of months it's gotten real bad, and another thing is when it sits for a few days it acts like the fuel bowl dries up (quadrajet) and you have to crank and crank to fill the bowl before it will fire. Do you think that this ethanel gas has ruined something in the carb. to cause this? When it's running it runs fine. I don't see any gas leaking on the ground or any working it's way into the crankcase. Thought maybe throw an old two barrel carb. on it if I could find one in decent shape. Could a bad fuel pump cause this. I don't use the four barrel anyway, just the primaries. Thanks for your help. RRM
  2. BurbanMan

    BurbanMan Rockstar 3 Years 500 Posts

    I would start with a rebuild. I had an 80's caprice with a 2 barrel that I put a Holley 4 barrel on and got the same 17mpg as I did with the dual jet. How many miles are on ol faithful? Obviously your not going to do better than 14-17mpg hwy in a 4500lb truck.
  3. Enkeiavalanche

    Enkeiavalanche Loving the Outdoors Staff Member 5+ Years ROTM Winner 5000 Posts

    Check the pump There should be a inline filter in the drivers side Frame rail replace that too.
  4. BurbanMan

    BurbanMan Rockstar 3 Years 500 Posts

    being an 82, the filters oe location would be in the inlet line of the carb.
  5. poncho62

    poncho62 Active Member 2 Years 100 Posts

    That filter in the carb usually has a check valve in it. If that screws up, gas will siphon back into the gas line, causing your slow start issue
    A 2bbl carb will get worse mileage than a Quadrajet, unless you have your foot in it all the time. Do a good tune up....plugs, cap, rotor, wires and your mileage should improve. A kit in the carb wont hurt either....and check for vacuum leaks (cracked hoses etc)
  6. tbplus10

    tbplus10 Epic Member Staff Member 5+ Years 5000 Posts Platinum Contributor

    If your unsure of when or if the carb's ever been rebuilt, being its a Quadrajet, a rebuild would be a good idea.
    Yes new fuel blends and addatives might be causing issues like bad "O" rings and or gaskets.
    Again being its a quadrajet Id recommend finding an old mechanic that knows them well, rebuilds on Q jets can be trickey if you dont know the carb well.

    2 bbl vs 4 bbl, remember the primarys in a 2 bbl are normally as large as the secondarys in a 4 bbl, which almost always causes 2 bbls to get a little less mpg than 4 bbls.

    If your running a mechanical fuel pump you may have leaks into the crank case, they wont always be obvious, normally theyll cause fuel starvation issues which may not be noticeable unless you get on the gas pedal alot.

    Yes the fuel filter should be at the carb inlet, given the trucks age its possible an aftermarket filter couldve been installed anywhere on the fuel line too, normally under the hood within 12" of the carb.
    I'd be tempted to remove the factory filter and use either a 5 or 10 micron aftermarket inline filter, probably a clear one that allows you to see any sediment being caught. The truck is 30+ years old and Id fully expect to see trash from the fuel tank getting in the fuel lines, probably rust from the tank too.
  7. Rat Rod Mac

    Rat Rod Mac New Member

    First off I want to thank all of you guys for responding. There is some good advise and suggestions here. Gives me a place to start. The mileage on the truck is around 160,000. Thanks again. RRM
  8. fugitive

    fugitive Member

    I had a 85 1500 and ran up over 200,000 on her in around a 8 year period rebuilt the quad on that thing twice you really have to make sure when you re-build to replace the welch plugs they will seap! I ended up buying the Holley replacement quad went from 20 mpg to 25 instantly this was a completely stock 305. I drove 45 miles one way to work all highway.

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