engine and drivetrain Distributor issue

[Guest Anonymous]

Hi all,

I have a 1974 2002 automatic that I recently disconnected the return fuel line and its corresponding vacuum return pump. I also removed the corresponding vac line that went to the fuel return pump. I now had an open vacuum port at the base of the carb and thought that I could connect a new vac line from it to the Distributor( which I ran for years with no vac line)> Here is the issue The engines RPM droped significantly and wanted to stall so I increased the idle speed by turning in the idle speed screw at carb. Why did idle Speed drop so dramatically?

and is there any adjustment I should make to Distributor or Carb since I conected vac line to it? I thought on Automatic distributor is Vac Retartded not advanced? , how would this play into this senario??

[Beaner7102]

With no vac line attached to the carb it was sucking air (running lean) and was probably tuned as such. when you connected up the vac advance line to the dizzy it basicaly plugged the hole (sucking only small air from the dizzy) thus richening up the mix and lowering the iddle. There is nothing wrong, but if you connected it and there was no change - then something would be wrong. Beaner7102

[Guest Anonymous]

Thank you fro speedy reply, but carb did have vac line from carb base to fuel diaphram pump before i disconnected and put to distributor. Idle droped only when I connected vac line from carb to distributor. so what could cause this condition? it seems hard for me to smooth out Idle now.

thank you for any advise.

[John7016002]

If your distributor has a vacume "motor" that when the vacume pulls it retards your ignition that would account for the lower idle speed as a retarded timing on an engine most certainly slowes down the idle. Have fun

[TobyB]

Dizzy vacuum is supposed to come from a port on the carbie, so that at idle, the dizzy DOESN'T see adavance,

but as soon as you tip in the throttle, it does.

If you are hooked up to the manifold directly, then

you're seeing full advance at idle, and as you've found,

that doesn't work very well.

Toby

[DukeRimmer]

Retard slows idle. I replaced dist. with an oldie from scottiesharpe. Made a huge improvment in power.