well its always something...
87 YJ 4.2L 258 - carter BBD recently rebuilt by me, i did the "nutter", and have bypassed most of the emissions stuff - including the charcoal canister, the O2 sensor, and the CTO. now here's the problem: following the instructions for the "nutter" i routed the dist. advance directly to the ported vacuum port on the BBD (the one on the valve cover side), in the process i discovered that i have no ported vacuum off this port at any rpm. i'm measuring directly off the carb so it cant be the hoses etc. i dont have a vacuum gauge but i have to assume that it would be detectable and that covering/uncovering the port would produce detectable change in the rpm etc. - i DO have manifold vacuum - quite a bit. also i can blow thru the ported vacuum port so its not clogged... here's the thing - she's running just fine, starts fine, no stumble, no hesitation, the only thing i notice is that she doesnt idle totally even. little mini-surges from say 600-700 rpm around 1 per second. so what gives? am i missing something? i thought the ported vacuum supplys the distr. with advance at low to mid rpm (from ~1000 - 2400) but like i said she seems to be running ok. just a little unsteady at idle. any ideas? sorry for the long complex post. i know some of you are going to say "if it aint broke..." and thats fine - i just want to understand this system... at least until i can replace it with something better... which given the state of my finances (somewhat limited) and the state of everything else on this thing (somewhat worn out) - is going to be quite a while... if ever :( cheers, bennett- posted
17 years ago