bryant2482 Posted January 19, 2014 Report Share Posted January 19, 2014 ok so heres whats going on, when my z24 gets warm or at normal operating temp it starts to pop or miss. when i have the vacuum advance line plugged into the dizzy it happend but when i pull it off it stops and runs smooth. do i need to retard my timing? Quote Link to comment
datzenmike Posted January 19, 2014 Report Share Posted January 19, 2014 The timing should be about 3 degrees BTDC is low warmed up idle. Check/set it and this may fix everything. Check and see if there is a vacuum signal on that hose at idle. It shouldn't have any, but maybe a hose is connected wrong. Is the idle too high? Quote Link to comment
bryant2482 Posted January 19, 2014 Author Report Share Posted January 19, 2014 there is only vacuum when its cold. then as it warms up the valve closes and keeps a constant vacuum between the dizzy and TTV. i have the dizzy line connected to the bottom port and the middle port is connected to the advance port on the weber Quote Link to comment
datzenmike Posted January 19, 2014 Report Share Posted January 19, 2014 The other end should NOT have vacuum at idle. It should be a ported vacuum on the weber that only sees vacuum when the throttle is opened. Quote Link to comment
bryant2482 Posted January 19, 2014 Author Report Share Posted January 19, 2014 Woops I messed up, I should have said that there isn't any vacuum at idel but when the engine is cold at fast idel is when it has vacuum. Then as it warms up the ttv closes and theirs a constant vacuum thats locked in (at idle and throttle open) Quote Link to comment
datzenmike Posted January 19, 2014 Report Share Posted January 19, 2014 OK here's how it's supposed to work... The carb, any carb, has a ported vacuum source that has virtually nothing to do with intake vacuum. The port is just above the throttle plate so at idle only normal atmospheric pressure is felt. (zero) When you step on the gas or if the choke is on with the fast idle, the throttle plate lifts over and above this port and intake vacuum is felt. The T V V has three ports on it. The top one goes to the air filter, the middle one goes the the EGR system, and the bottom line to the distributor advance and the charcoal canister. In action when the motor is cold the top port is open to the air and is a vacuum bleed. When cold any ported vacuum is lost out the bleed and has no effect on distributor vacuum advance nor EGR. As the water temp goes up the wax pellet in the T V V melts and slowly blocks off the vacuum bleed to to air filter. When warmed up, vacuum is supplied to the distributor advance and the EGR BUT only above idle Quote Link to comment
bryant2482 Posted January 20, 2014 Author Report Share Posted January 20, 2014 do you have a diagram how it should be hooked up for the weber? Quote Link to comment
ggzilla Posted January 20, 2014 Report Share Posted January 20, 2014 Just plug it. Quote Link to comment
bryant2482 Posted January 20, 2014 Author Report Share Posted January 20, 2014 Can't, got smog checks every year Quote Link to comment
datzenmike Posted January 20, 2014 Report Share Posted January 20, 2014 There should be ported vacuum on the side of the carb. The 720 had three so I don't know about the weber. Just plug it. . This would disable the vacuum advance also and give poor part throttle performance. Quote Link to comment
bryant2482 Posted January 21, 2014 Author Report Share Posted January 21, 2014 ok cool this makes perfect sense to me! thanks mike! Quote Link to comment
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