fast idle cam
Thread Starter
Melting Slicks
Joined: Feb 2000
Posts: 3,052
Likes: 0
From: Vancouver BC, Canada
fast idle cam
Q-Jet on stock 72 454ci
attempting cold start, fully press throttle to set choke
is the cam follower supposed to engage on the high step or 2nd step by default?
high step, choke is 100% closed
2nd step, choke is 3/32" open
attempting cold start, fully press throttle to set choke
is the cam follower supposed to engage on the high step or 2nd step by default?
high step, choke is 100% closed
2nd step, choke is 3/32" open
Thread Starter
Melting Slicks
Joined: Feb 2000
Posts: 3,052
Likes: 0
From: Vancouver BC, Canada
how can the engine start if the choke is 100% closed? air through idle air bypass is enough? i guess the blade will crack open a bit due to air pressure when cranking, but only 1mm or so.
if i adjust the choke blade rod to achieve the 3/32" gap on the second step, the cam+lever does not have enough travel to reach the high step when cold starting. how important is this distance? should adjust it so that it goes to the high step instead?
if i adjust the choke blade rod to achieve the 3/32" gap on the second step, the cam+lever does not have enough travel to reach the high step when cold starting. how important is this distance? should adjust it so that it goes to the high step instead?
Tech Contributor
Joined: Aug 1999
Posts: 14,384
Likes: 6,409
From: At my Bar drinking and wrenching in Lafayette Colorado
The choke should snap fully closed,and the fast idle will be on the high step of the cam. The instant the engine fires and starts to run, the choke pulloff then cracks the choke open 1/4" to allow adequate airflow. If you then tap the gas pedal, the cam should drop down to the next step, allowed by the fact that the pulloff cracked the choke open.
If you drop me an e-mail, I'll send you my choke setup article:
V8FastCars@msn.com
If you drop me an e-mail, I'll send you my choke setup article:
V8FastCars@msn.com
Pro
Joined: Apr 2005
Posts: 666
Likes: 5
From: Mt. Pleasant SC
lars is correct. I should have stipulated "cold start". When you fully depress the excellerator for a cold start the choke plate is fully closed. As engine comes up to operating temperature the choke plate moves to full open position.
lars, I would be interested in your choke setup article too.
lars, I would be interested in your choke setup article too.
