I purchased a 74 Duster that has been converted from a I6 to a 318. The engine runs great and smooth when not in gear. The engine will die when placed in gear unless the idle is set high. The car runs and drives fine other than the need to be at high idle to keep running. It is a stock engine with an Edelbrock 4 barrel carb and aftermarket intake with headers. I am not sure if this is a carb tuning issues or maybe a torque converter issue. Any ideas or thoughts on where I should start to address this issue?
74 Duster 318 with 904 Trans
- Thread starter winfirst
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transman
Well-Known Member
Personally, I'd start with looking for vacuum leaks and other tuning issues. Just for chuckles, check the air cleaner element. Why do I say this, because I once had the same issue. Plugged and didn't want to idle properly. I don't know what converter issues would come into play.
Professor Fate
Push the button, Max...
Could also be an initial timing issue.
Assuming a relatively mild cam, and a vacuum advance is present;
Disconnect the vacuum advance and plug the port. Advance the timing until the engine sounds happiest, probably between 10 and 15 degrees before TDC. Adjust your idle back down to around 800 rpm if you can, or close as you can get. Recheck timing. Might have to go back and forth a few times.
Then reconnect the vacuum advance and try it out.
PS- make sure your vacuum advance is connected to ported vacuum, not manifold vacuum.
Assuming a relatively mild cam, and a vacuum advance is present;
Disconnect the vacuum advance and plug the port. Advance the timing until the engine sounds happiest, probably between 10 and 15 degrees before TDC. Adjust your idle back down to around 800 rpm if you can, or close as you can get. Recheck timing. Might have to go back and forth a few times.
Then reconnect the vacuum advance and try it out.
PS- make sure your vacuum advance is connected to ported vacuum, not manifold vacuum.
remytherat
Well-Known Member
Sounds like not enough initial timing to me.
Locomotion
Well-Known Member
See if it helps any to turn the idle mixture screws 1/2 - 3/4 of a turn out from what's optimum in neutral.
AJ/FormS
68 Formua-S fastback clone 367/A833/GVod/3.55s
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My guess is that at idle, the Transfer slots are inactive/or nearly so, and the mixture screws are cranked rich.
Plumb the VA to the sparkport,
Reset Idle-timing to 10*, and
mixture screws to, in the center of their range, (~2.5 turns out on just about anything besides a Holley), and
Then increase the rpm to whatever doesn't bang the trans on the N>D shift, but also eliminates the Tip-in Sag.
This will be your starting point.
Plumb the VA to the sparkport,
Reset Idle-timing to 10*, and
mixture screws to, in the center of their range, (~2.5 turns out on just about anything besides a Holley), and
Then increase the rpm to whatever doesn't bang the trans on the N>D shift, but also eliminates the Tip-in Sag.
This will be your starting point.
What year is the trans? Is it a lock up? Kim
I believe the trans is the original that came in the car. The I6 was removed and replaced with the 318 which I am thinking is around a 1976 engine.
U would need a different tranny for the swap as a slant tranny won’t fit a 318
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