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More running problems

Discussion in '40- & 55-Series Tech' started by offcamber40, Dec 26, 2003.

  1. offcamber40

    offcamber40

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    Ok, I had some bad running problems after my rebuild. It would miss and stall out at Wide open throttle. I was able to depress the throttle slowly and rev it out no problems. After pulling stuff apart and re-sealing for vac leaks etc, i re-timed it and adjusted the new weber, but still had the same problems.. I pulled off the fuel pressure regulator and it ran fine, so I thought the problem was solved. After getting the car back from being painted, it ran fine, I put the air filter back on and replaced the exhaust, fired it up, and it runs like hell, way worse than before.. No joke, all I did was put on the stock filter assembly, and put on a MAF header back exhaust.. It is sputtering and missing all over the place.. the idle keeps coming up and down. What would cause this itermittent fuel problem? My fuel filter had some debris in it when I replaced it last time, could the tank be the problem? Have you guys ever had problems with the factory pumps not putting out proper flow intermitently? This is starting to annoy me. Right now it is on a truck being shipped to my new home in colorado.. I will have to deal with this when I get out there in January, so any help now would be appreciated.
     
  2. IDave

    IDave

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    recheck for vacuum leaks. you may have tweaked the header in you exhaust install.
     
  3. Pin_Head

    Pin_Head

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    Vacuum leaks show up most at idle, so your WOT stalling problem is not a vacuum leak. It is a fuel delivery problem and you need to check everything form the tank to the carb nozzles. If you found junk in your fuel filter, you can be sure there is more in your tank; maybe even enough to block the flow. Have your tank cleaned out and reaseled at your local radiator shop. Check the flow by disconnecting the fuel line at the carb. Disconnect the coil wire and measure the amount pumped in 10 seconds of cranking. It should pump at least 1/2 cup in 10 sec. Also check the fuel bowl level when it stalls out. If the bowl is half way full in the sight gauge, then it is probably not a fuel pump/supply probelem; it is the carb.
     
  4. Poser

    Poser Oh...Durka Durka Durka. s-Moderator Supporting Vendor

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    Offcamber:

    I run a 38 weber on my truck. At one time someone put a bunch of sand and other crap in my fuel tank. I replaced the fuel filter many times, and it had crap in it every time. I now run three. :)

    I had to remove the top of the carb, and get the crap out of the float bowl before it would run properly again. I would take the top off this carb when you get the chance, and see how much crud is in there. You will probably be amazed, as I was.

    I drained and rinsed my tank, and installed a fuel filter in the line directly out of the tank, just under the body, and then also put one just before the carb. Fuel filters are cheap, and easy to install, I would suggest at least one more after you get this figured out.

    A customer had his truck pianted and I found the same problem with his weber and fuel system....There was over a .250" of blasting sand and other crap on the screen that I filtered the fuel through. What a mess.

    Good luck!

    -Steve
     
  5. Poser

    Poser Oh...Durka Durka Durka. s-Moderator Supporting Vendor

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    Weber carbs do not have a sight glass.

    I had fuel in the float bowl, and a little piece of crap was blocking a fuel delivery port, and the engine would not run properly.


    Good luck!

    -Steve
     
  6. offcamber40

    offcamber40

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    Thanks for the responses guys. This whole thing is annoying me b/c everything is brand new and shouldnt be all gummed up yet. It has a total of 10 miles on it since the rebuild. At this point it seems like it is overfueled by the fact that there is a good amount of black smoke blowing out at full throttle. But again, it misses and backfires like its fuel starved or the timing is off. Another related question, The gas tank appears to be over pressurizing for some reason. When I pull the cap it "exhales" out the filler neck.. would this cause a running problem? Im not sure what would be doing it.. the charcoal canister or the fuel seperator maybe? I never did understand this part of the fuel system.. LOL.
     
  7. fsusteve

    fsusteve

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    Kinda sounds like it's running rich or the float's stuck. Did it sit for a while when getting painted (bad fuel)? I'd also check what Steve says, sounds like a good start.
     
  8. Pin_Head

    Pin_Head

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    Just because it has been rebuilt recently doesn't mean that it was rebuilt right. I would take it back to who did the work and bitch.
     
  9. offcamber40

    offcamber40

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    I did the rebuild myself, everything new or refurbrished, I may have to be kicking my own ass! :D :D