badjuju Posted October 10, 2006 Share Posted October 10, 2006 I understand quite well that an L4 is not in fact a 6 cylinder engine, however it's so close to an L6 that I thought I'd ask here. I just bought a 77 620 pickup, and it kinda tries to keep running after I shut it off. It kinda sputters, rocks the engine around a lot, and at the end of this it usually backfires. I'm wondering, how do I fix this? Is it a tuning issue? Is it still getting power from the alt? Quote Link to comment Share on other sites More sharing options...
mario_82_ZXT Posted October 10, 2006 Share Posted October 10, 2006 Idle too high, timing could be off, mixture could be off as well. Mario Quote Link to comment Share on other sites More sharing options...
510six Posted October 11, 2006 Share Posted October 11, 2006 Sounds like your timing is way off. Quote Link to comment Share on other sites More sharing options...
Tony D Posted October 11, 2006 Share Posted October 11, 2006 Check to see if the carburettor has an idle cutoff solenoid. It should shut the fuel passage in the idle circuit when you key-off. This keeps it from doing those dieseling things. VW Used them since the late 60's, and it really made a difference when you ran cheap gas! Quote Link to comment Share on other sites More sharing options...
badjuju Posted October 11, 2006 Author Share Posted October 11, 2006 my dad's 67 chevy c10 does the same thing, but without the backfire, thank god Tony, where would the idle circuit be? Quote Link to comment Share on other sites More sharing options...
Tony D Posted October 11, 2006 Share Posted October 11, 2006 Usually a little silve solenoid sticking out form under the air cleaner, screwed into the side of the carburettor. It should "click" when you turn the key on and off. Another symptom of a failed idle cutoff is the you have to idle the car waaay up in rpm (like to 1500+ to keep it running, as the thing won't idle at all without you hitting the gas to keep it running. They both go hand in hand, usually you won't get one without the other, sooo..... Like said above, if you have timing advanced too far for the fuel that you are running it can run-on afterwards as well. Same for if you are percolating in the carburettor, and bubbling gas down the carb throat after shutdown... (running hot) Best thing to di is strike the air cleaner and observe what you see after a shutdown and go from there. If you aren't seeing fumes, pukeover, or etc, it can probably eliminate a fuel issue. Man, I gotta get going to work. BAH! Good Luck! Quote Link to comment Share on other sites More sharing options...
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