jonaona

My question is: what’s the likely cause and what’s the fix? I’m moderately handy with cars. This is a car I purchased recently. (I have three other El’s, but have never seen this problem.) The car sat for three years before I got it. Seller said it had carburetor problems. 106k on the odometer. Symptoms at present (persisting after some attempted fixes): 1. black smoke on start-up 2. black smoke while driving but at a lower level 3. more dense black smoke upon acceleration 4. misses upon start-up, then evens out I have done the following: a. replaced plugs; originals heavily carbonated b. replaced distributor cap c. changed oil d. > > > swapped the carb from another 305 from an El that had been running well but has 238k < < <
e. treated the gasoline and added more new gasoline Any advice will be GREATLY appreciated. Thank you taking the time to respond!

Cobra454x

First of all, Welcome to the forum, i think youll like it here....


Had the other El camino been sitting for any length of time prior to your carburetor swap? the reason i ask is because in '84, GM was using their ever popular quadrajet carburetors, and if memory serves.....a 500cfm or 675cfm version of it was put on the elkys then...

They're great carburetors for reliablilty and longevity, but they are notorious for gumming up internal vacuum chambers and critical runners for the carburetor's proper operation. This generally happens if the carb has been sitting for any length of time (about 90 days, sometimes sooner if conditions are right). I've run into this before....the car refuses to run correctly, always rich, horrible idle quality and eventually fouling plugs...I've messed with them in the past as far as recalibrating the carb, and sometimes going WAAAY past the normally safe levels on the mixtures, but my attempts have always turned out to be in vain...once they get gummed up....you might as well just pitch it or rebuild it...

My reccommendations to you would be to go to your parts house of choice and do one oftwo things.
1) if your really ambitious and are handy with rebuilding carburetors, then go get a gallon of carb cleaner and a rebuild kit. BUT be forewarned, these carburetors are fairly complicated inside and are easily screwed up.
2) go out and get you a remanufactured quadrajet carburetor or if your like me and don't particularly like the QJ (im a performance nut, :-P) you can buy a holley carb thats a 100% direct replacement for the QJ. last time i checked on them, they run the same money for the remanned and the holley replacement....about $350

Hope this helps you out. I've been having my 86 c-10 driving me up a wall w/ the damn brakes on it....perhaps you could go check what ive posted out and put in your two cents on that. any input would be greatly appreciated, im getting ready to throw a grenade at that thing, lol....anyways, hope my two cents was of some assistance to you. look forward to hearing from you...