Slant six dies in gear

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Emma Godolphin said:
I’ve run into a bit of a new problem now. Just a few days ago the replacement carb came in and we installed it with no issues. Made sure the jets and everything were clean. The car now refuses to idle below 25* and 1200rpm. Obviously it’s not drivable at that rpm so it’s at home right now. I’ve attempted to slow the rpm and lower the degrees by using the throttle every once in awhile to keep it running but no luck. I’ve had me look at it, and quite a few family members who are mechanics or heavy duty’s and we’re all stumped. I’m wondering if we caused an issue when we replaced the head. The head was from a 1975 slant six (we replaced it before we knew the engine was older and just before these issues began.) at this point the goal isn’t been running right but to get her to idle at all
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I'm not that familiar with the slant six carbs and their replacements.
However, since this happened after changing the carb I would suspect the carb or the changes (vac hose rerouting or similar) that occured with the change.

Before going back to the previous carb, see if the reason for high idle rpm can be narrowed down.
For example, where is throttle positioned and what is holding it ? Is it on the slow idle stop or is the the throttle being held open on the fast idle cam's step?

Here's an illustration of the cam on a '73 BBD carb
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Some photos of the current setup would help folks on this end see what versions/model of carb and emissions systems are on the engine. Some sharp eyes and knowledgable folks here.
 
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In the Master tech series, it shows a solenoid on some carbs starting in '75 designed to work with a speed sensor to protect to the cats.
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These additional systems aren't that hard to understand but if not aware of them can really cloud the picture.
 
Emma Godolphin said:
I’ve run into a bit of a new problem now. Just a few days ago the replacement carb came in and we installed it with no issues. Made sure the jets and everything were clean. The car now refuses to idle below 25* and 1200rpm. Obviously it’s not drivable at that rpm so it’s at home right now. I’ve attempted to slow the rpm and lower the degrees by using the throttle every once in awhile to keep it running but no luck. I’ve had me look at it, and quite a few family members who are mechanics or heavy duty’s and we’re all stumped. I’m wondering if we caused an issue when we replaced the head. The head was from a 1975 slant six (we replaced it before we knew the engine was older and just before these issues began.) at this point the goal isn’t been running right but to get her to idle at all
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You also replaced the timing chain? Are you sure it was installed correctly? Your new carb is no good, the old one was better. Please post pictures of your engine, distributor, and carb.
 
Late 69 engine would have a points dist, if original. Stalling when putting into gear is a symptom of points gap having closed up. In P or N, higher rpm supplies enough centrifugal force to just open the points & create spark. In gear, rpm is lower, & points stay closed & engine stalls.
 
Bewy said:
Late 69 engine would have a points dist, if original. Stalling when putting into gear is a symptom of points gap having closed up. In P or N, higher rpm supplies enough centrifugal force to just open the points & create spark. In gear, rpm is lower, & points stay closed & engine stalls.
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:rofl: :rofl: :rofl: :rofl: :rofl:
 
I would check to make sure you don't have the vacuum advance attached to manifold vacuum. That could cause what you're describing now. You can do that, BUT you must adjust the timing accordingly. For now, I would make sure it is attached it to ported vacuum until you get it sorted out. Look, I know you're only 18, but there have been several pointed questions asked that have gone unanswered. We need some input from you, if you want our help.
 
i'm reading this as: it was over heating, so i did all this. but that didn't fix it so then i did this, and while i was there i did this, this and this. but then it wouldn't start, so i did this. then this and this. well, now it starts and it runs pretty good but it dies in gear.

there are a LOT of variables here that are going to make this a difficult basket full of snakes to untie. carbs and distributors on and off, parts interchanged and intermingled, other parts substituted. none of this is conducive to an effective repair.

but! it runs, so you're on the right track!

at this point, i'd go back to basics. verify the timing chain was installed properly, check and set the valve clearances, check for vacuum leaks, reset the timing and carb to factory specs. if you can borrow a known, good carb for testing purposes do so.

get a copy of the FSM and a vacuum gauge, they'll be extremely helpful in diagnostics and tuning. there are some very sharp people here, answering the questions that they ask will help everybody get a better picture of what's going on.
 
Bugman said:
1976 emissions manual certain six and 318 were manifold vacuum advanced from factory.Worked fine but carb and distributor had to be right part numbers. Dist for ported would not work too well with manifold vacuum carb, base timing different 76 emissions and TSB,s - Slant Six Forum
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Thanks Bugman.

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Be nice to see the rest of TSB 25-05-76
Looks like may have been a mid year change back to ported with substantially increased initial timing. Need to see the rest of the details to know for sure.
 
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Toolman,
Post 30/31. You may well laugh until it happens to you, but it just shows ignorance. It was a very early lesson I learned when my Ford Customline failed to proceed one day. Any old time mechanic will tell the same story.
 
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