Engine Fuel gremlin...carb issue?
UncleMike
Jeeper
My 1979 CJ7 304 with Edelbrock AVS2 carb has had a periodic issue. I recently was able to pinpoint the conditions under which the issue ocucrs, and now I'd like to figure out the actual cause and remedy. I'm reasonably inexperienced on carb tuning and diagnostics but get the basics. Carb and manifold installed by PO and generally has run great.
Issue happens after a hard, full-throttle acceleration, followed by an equally hard deceleration. First time it happened, ran poorly after this event under low throttle and at idle, stumbling and even stalling. Thought initially ran out of gas (bad sender to be replaced as a winter project), so topped off. Still rough. Checked and adjusted timing per FSM (pretty close already, minor adjustment made). Checked idle...within FSM specs. Acted like it was flooded. Gas was a little yellow and didn't smell good, so thought i had a bad tank...drained tank, ran it till it died, and all fuel was out of filter, changed filter, and added fresh tank. Ran great. Thought it was just bad gas.
Happened again last night, after i goosed it good while giving some kids a ride around the block (low speed, but 6-years scream like a roller coaster!). Wound up stalling out and running terrible...same as before. Now I believe it is a direct result of this immediate and full throttle, followed by an immediate lack of throttle. Google suggests vacuum advance (less likely) and accelerator pump. I have noticed when it was running really well that i had a periodic hesitation on accelerating but not all the time, and not bad.
Wanted to get thoughts on sequence of diagnosis, repairs, etc...before i just pull the carb and start rebuilding it, which I'd rather not do if i don't have to before i put it up for the New England road salt season....like i said, it ran great until i did the stupid goosing, and i can not do that in the future and keep enjoying my car while we have good weather.
Issue happens after a hard, full-throttle acceleration, followed by an equally hard deceleration. First time it happened, ran poorly after this event under low throttle and at idle, stumbling and even stalling. Thought initially ran out of gas (bad sender to be replaced as a winter project), so topped off. Still rough. Checked and adjusted timing per FSM (pretty close already, minor adjustment made). Checked idle...within FSM specs. Acted like it was flooded. Gas was a little yellow and didn't smell good, so thought i had a bad tank...drained tank, ran it till it died, and all fuel was out of filter, changed filter, and added fresh tank. Ran great. Thought it was just bad gas.
Happened again last night, after i goosed it good while giving some kids a ride around the block (low speed, but 6-years scream like a roller coaster!). Wound up stalling out and running terrible...same as before. Now I believe it is a direct result of this immediate and full throttle, followed by an immediate lack of throttle. Google suggests vacuum advance (less likely) and accelerator pump. I have noticed when it was running really well that i had a periodic hesitation on accelerating but not all the time, and not bad.
Wanted to get thoughts on sequence of diagnosis, repairs, etc...before i just pull the carb and start rebuilding it, which I'd rather not do if i don't have to before i put it up for the New England road salt season....like i said, it ran great until i did the stupid goosing, and i can not do that in the future and keep enjoying my car while we have good weather.
