fuelie65

I have just put the distributor back into my car ( a different one than what I ran prior ) and noticed while I was setting the timing that when I connected the vacuum line back on to the advance dashpot my rpms jumped considerably....from 850 to about 1700 !!! It is the correct # 236 advance

seems to run better with out the line connected...any help from the experts ?

Its a 375 hp fuelie

AZDoug

Mkae sure the diaphragm in the vac can isn't blown and giving you big vacuum leak, vac leaks are real good at raising RPM's.

Doug

JohnZ

That's perfectly normal behavior - when you re-connect the vacuum line to the vacuum advance unit, it adds 15* of advance to your static timing, which increases idle rpm; just re-adjust the idle speed screw to your normal idle rpm.

fuelie65

I tried that John but with the timing at 10 btdc I can't get the settings on the fuel injection right to get the idle below 1500.

wmf62

here's what i suggest, in this order:

1. get it to idle at the lowest practical rpm, 850 would be great.... (with the vacuum advance disconnected and plugged)
2. check/set distributor dwell
3. set the timing to the factory spec, with the vacuum advance disconnected and plugged.
4. reconnected vacuum hose to can
5. use a vacuum gauge to adjust the idle mixture screw on the air meter to the highest vacuum reading (connect the gauge to the vacuum advance hose using a 'tee' if you like)
6. adjust the idle using the LARGE idle air screw, do not touch the idle mixture screw
Bill

fuelie65

thanks Bill..