idle dies

[joshua dewitt]

ok, I have been playing today...73 dart 318 with 340 cam and 302 heads.
I did also but a lighter spring in the distributor on one side... when in park or neutral ok. but in gear, and it takes a moment or idle to lower down before goes into gear, too high of idle won't go into gear until around 1000 rpms or so. fixed all the vacuum leaks, new parts, brand new carb form summit, 4100 series. removed brake booster form the equation. idle mixture about right timing around 16-20 to stay running, reset to 12 right now at idle, and distributor vac. .line removed. and carb plugged. floats adjusted to specs, getting plenty of fuel, now the a904 l/up for 1978 is in the car, has a supposedly mild shift kit, done before I got it, I added 5:1 kick down lever, and adjusted the band accruing to information on internet. , once it goes into gear does ok, and shifts ... car on jack stands..... using e-brake and in drive, tried to idle then ends up dyeing out, possible timing still? or maybe am I looking a failing torque converter?, I got it used..... but supposes to work... or is it my distributor spring too light? I'm about frustrated right now with is, runs awesome, sounds great but i can't get it to idle in gear below 1000 rpms....? any thoughts I may over looked?

 

[joshua dewitt]

not asking any of you to build my car. just a little stumped... because I never have had or been a round a a904 lock up before, just not sure hoe to tell if a converter /trans issue or something with y idle/timing.....???

 

[dano]

If the carb has a choke, the electric need hooked up or the manual wired open if not in use. If your choke is sorted then is it hanging up on high idle? Are you getting too much fuel? If the throttle cable holding the carb open a tad? Do you have a strong return spring?

Form your description its hard for me to grasp what is going on, are you saying it idles fine in park/neutral then idle speed increased when you put in gear?

 

[AJ/FormS]

The three things that control hot idle speed are; T-port sync, secondary cracking screw, and ignition advance.
If you cannot get the idle speed down, and these three are tuned, then she is getting air somewhere.
I would start with proving the TDC mark.(your idle-timing is fine)
Then,I would set the T-port sync
And then I would control the idle speed by the secondary cracking screw.

BTW; the idle timing has the biggest control. So if the T-port is synced, and the secondaries are closed up tight(short of sticking), and you have proven that she is not getting air from any other source, then back up the timing.

The following line;" but in gear, and it takes a moment or idle to lower down before goes into gear, too high of idle won't go into gear until around 1000 rpms or so. " tells me your transfers are likely feeding when they ought not to be. Dry 'em up

 

[joshua dewitt]

the idle will go down and can be controlled, the idle gets tow low and dies in gear is my problem, will be too high in park or neutral then, but what is weird is if I am in gear give it a throttle up holding brakes should die immediately since wheels not turning, kind of wants too, but acts like letting loose like a bad stator in the converter. just putting out feelers for some insight. I used on light spring and one original spring on the factory electronic 318 distributor. from what I have been reading I my need more initial base timing, closer to 20... sound right? ran ok there, but never tried to idle it there..

 

[AJ/FormS]

Your springs are fine,and so is idle timing between 12 and 16(with v-can disconnected/plugged). It should idle fine in gear at 550 or even a tad less.And it should not jump up more than 100 to maybe 150 in Neutral.
That it does not, seems to indicate that either, the intake valves are leaking(possibly the lash is too tight) or the carb is lean. The valve lash is easy to prove with a leakdown test, but if your vacuum is about 12 inches or better at 700rpm, then I wouldn't bother yet.
So that takes us to lean idle circuit. And that takes us back to post #4; the TDC mark,the T-port sync., and the cracking screw.

 

[threewood]

Cam?
Carburetor?
What is your idle rpm?
Rpm in gear?
Vacuum at idle?

Did you set your initial timing at or near max vacuum? I'm not an expert by any means but from my experience the more initial you run , the more you have to reduce the curb idle screw (lower the rpm), which shuts the butterflies more covering the T ports, which gets you into the idle circuit. Check your throttle cable too because it can hold open the butterflies. Unhook it and make your adjustments just to be sure.

At idle, around 650rpm or so, check timing mark. Should be pretty steady. If it is bouncing around your mechanical advance may be kicking in which would cause it to bog and die when put into drive.

 

[mguner]

Ignore your timing light for a little bit and just crank the distributor to where the engine runs best and then check your marks. Could have a balancer that has a slipped ring or may be off a tooth on the cam gear..... The slow return to idle speed screams vacuum leak somewhere..... Do you have another known good carb?