I have a pro systems 780dp. I ordered it a few years back for my 406. It had performed flawlessly until last spring. When I ordered it and until last spring I was running 1 5/8 headers with a 2 1/2" flowmaster exhaust with the H pipe.
Worked perfect
Early last spring I installed 1 3/4' headers with 3" pipe to a X and retained the 2 1/2' tail pipes. When I fired it up I was unable to control the idle. It idled at a high rpm, around 1200rpm. Even if I turned the 4 idle mix screws in all the way. I just couldn't bring the idle back down. I could close the buttlerflys completely, it still would keep running at a high idle.
My carb came with holes drilled in all 4 butterflys. I then took the carb off and sealed the 4 holes. Reinstalled and fired it up. Voila!, I had control again. I ran it this way all last year with really no issues but I keep trying to come up with an explanantion of why this happed.
Any carb guys that might be able to provide some insight into this?
Worked perfect
Early last spring I installed 1 3/4' headers with 3" pipe to a X and retained the 2 1/2' tail pipes. When I fired it up I was unable to control the idle. It idled at a high rpm, around 1200rpm. Even if I turned the 4 idle mix screws in all the way. I just couldn't bring the idle back down. I could close the buttlerflys completely, it still would keep running at a high idle.
My carb came with holes drilled in all 4 butterflys. I then took the carb off and sealed the 4 holes. Reinstalled and fired it up. Voila!, I had control again. I ran it this way all last year with really no issues but I keep trying to come up with an explanantion of why this happed.
Any carb guys that might be able to provide some insight into this?
