idle problem.extremly frustrating

[alex]

Hello,I'm hoping for some help with this.I put a amc 360 in my cj7 and everything is fine except for this.When I first start the jeep it starts right up,it idles fine.When I take off down the street and get about 1 mile down the road to my first stop it will barely idle.The funny thing is,if I take the the vacuum hose thats supposed to go to the brake booster and let it suck air,the engine picks right up.The carb is new.The vacuum advance is working,the timing is dead on.If I shut the jeep off and restart it ,then it will idle just fine untill I hit the gas peddle one time.I have never heard of an engine running better when all the vacuum hoses are left open.This is the second time its done this to me.Any info would be greatly appreciated.

[tufcj]

What carb are you running? I had a similar problem with my Holley when the bi-metal electric choke spring broke. When it idled, the vacuum was low enough that the choke flap would fall closed as soon as I tapped the pedal. When it revved, the vacuum would pull the choke open, and all was fine. That would kind of explain why it runs better with the vacuum lines open, it's starving for air, and loading with fuel.

Check things with the air cleaner off, and watch the choke.

Bob
tufcj

[bushwackertn]

It sounds to me like your idle screw is set to low, when you first start it the choke idle wedge is advanced and then when you hit the gas the first time the choke idle wedge falls out letting your engine idle low because you idle screw is not adjusted correctly.

Thats my .02 cents worth, might help you, and it might not. Something to look at anyway.

[alex]

I,m running just a stock motorcraft 2150 2 barrel carb.The flap does stay open when the choke is off.I will double check though.The idle screw is set to specs.I just purchased it from national carb. and it was put on an engine and tested.I also put the vacuum gauge on a port on the intake and I slowly increased the idle and the gauge did'nt show normal engine vacuum till half throttle.I am going to recheck the vacuum lines according to print.Could the egr valve cause this?

[alex]

Good news,after checking everything out,it turned out to be just the idle adjustment!I know I probably sound stupid but the rebuilt carb was set for an electric dashpot for the idle,and I did not have one.Thanks for the help.One thing that also is positive is I found some great websites with good detailed vacuum hose routing.tom ol jeep collins fsj vacuum line routing.both reply's are appreciated,heck the one was right on the money!! :sa:

[bushwackertn]

No problem there Alex, I get stumped allot myself and it is usually something simple that someone points out to me. Holler if you need anything else. I'll try to help if I can. Good luck, and keep wheeling :lo1l: