TC problems

[Grey owl]

Made the mistake of not researching the converter for a C4 conversion. Now I have a problem. The trans builder souced the TC thinking it was stock specs. The problem is it won't idle in gear. Pulling up to a red light it's like i have a standard and am not the pushing in the clutch the engine just stalls. I can turn up the idle to 12-1500 but the result is having to stand on the brakes. Needless to say it's not fun to drive at all.

What TC is best when the #1 priority is just a nice driver. One that will allow the engine to idle smoothly at 800 rpm when stopped but in gear. The current situation is not acceptable.

Motor runs great 20 degrees of initial timing, carb set properly no vacume leaks, it's a bone stock 302 no power adders stock cam.
Thanks

 

[73azbronco]

should idle fine at 600-800 rpm, you say it wont?

 

[Broncobowsher]

20° initial timing is a lot. Probably why you can't get good idle performance. Stock is something like 6 and many bump to 10 or maybe 12.
Do you have the vacuum advance hooked up? Ported or manifold vacuum?
Points ignition? Is the dwell set right?
Have you checked for vacuum leaks?

 

[Grey owl]

HEI distributor, no vacuum leaks manifold vacuum, could move the timing back to 10

 

[Broncobowsher]

Change the manifold vacuum to ported vacuum. You are shooting yourself int he foot by using manifold vacuum on the vacuum advance.

Idling in park you are pulling strong vacuum. The throttle is extra closed trying to hold back the excessive vacuum with minimal airflow.
Putting a load on the engine there isn't enough airflow to keep the engine at the idle speed. RPM drops, vacuum drops, vacuum advance drops, less timing, lower idle speed. Lower idle speed, vacuum drops, now there is no vacuum advance. And you had been counting on that excessive advance to keep the engine at idle speed.

Some EFI engine will use timing to control idle speed. At least fine tune it faster than the IAC can handle it. Early Chrysler EFI does it. Sniper has an option to use it. Timing can change idle speed way faster than an IAC can respond. In your case that is hurting you. Dropping into gear drops vacuum, and that pulls timing, engine stalls.

Move the vacuum advance, set base timing back to 10°, set idle speed at that setting. Might have to go and reset idle mixture screws as well. That will make the engine much less sensitive to load placed on it. Idle vacuum won't be as high, but that will help you.

Side benefit, it will slightly clean up idle emissions. You will have a little more cylinder pressure at idle which will help burn the fuel more cleanly.

 

[Grey owl]

Thanks I will give this a try.

 

[Grey owl]

Made all the adjustments but nothing changed as soon as it goes in gear it draws the engine down and it stalls. I am convinced this is a converter issue

Thanks I will give this a try.