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C-4 Auto, Engine dies when shifted into gear

Madgyver

Bronco Madman
Joined
Jul 30, 2001
Messages
14,678
Engine dies when shifted into gear. I've bumped up the idle but it's too fast in park or neutral and when put into gear its just right. I don't have a tach to see rpms but I know the drop is too much.

Is this a carb problem or auto problem?
Looking for quick answers. Ive swapped carbs and got the same thing but how could it be an automatic problem?

Thanks,
madgyver
 

sicaz66

Bronco Guru
Joined
Aug 14, 2001
Messages
1,951
Loc.
san diego
do you have an msd ign box? if so that is what was driving me nuts for weeks before it totally died.
 

BwoncoHowie

C-4 Wizard
Joined
Nov 11, 2002
Messages
3,571
Did you put a vaccuum gauge on it? Sometimes an automatic trans will kill the motor if the ign timing is off or a vaccuum leak is present or perhaps a combination of both. What kind of cam are you runing?
 
OP
OP
Madgyver

Madgyver

Bronco Madman
Joined
Jul 30, 2001
Messages
14,678
BwoncoHowie said:
Did you put a vaccuum gauge on it? Sometimes an automatic trans will kill the motor if the ign timing is off or a vaccuum leak is present or perhaps a combination of both. What kind of cam are you runing?
Stock 77 302 and stock ignition.

I will hunt for the vaccuum leak. I may have to reinstall the performer intake and seal it up better.
 

Blue71

Contributor
Bronco Guru
Joined
Aug 27, 2001
Messages
5,144
Hey Mad,

Justy tracked mine down. was driving me nuts when ity would die in Forward or revers. I put a vacuum gauge on the manifold forst to see what it was there and it was like 19 or so. Put it on the carb and got 10. New there was a vacuum leak on the carb. It actually was on the baseplate gasket. I got a new gasket and some sealer and it works nicely now. Give that a shot. CCheck all those vacuum lines. Good luck Braddah

Andy
Blue71
 

j.r.nice

Bronco Guru
Joined
Feb 8, 2004
Messages
1,615
Almost everytime I have read this complaint, it ended up being the problem. I dont think they are that expensive. I would take the gamble and just switch it out.

(but that's just me!)
 

taipeichris

Bronco Guru
Joined
May 11, 2006
Messages
1,752
To test if the vacume leak is on gaskets, get a can of carb starting fluid and a good fire extinguisher just incase.

HA! Start the engine and carefully spray around the base of the carburetor, intake manifold, or there possible gasket sealed areas. If there is a vacume leak the idle will increase from the consumption of the carb starting fluid.

BECAREFUL NOT TO OVERSPRAY! THIS STUFF IS VERY FLAMABLE!!!

Also, check for brittle vacume hoses and any missing vacume caps or cracked caps too. They may look ok but can be split length wise.

Is this a new problem? Have you recently changed/removed the distributor? There is a vacume part on the distributor that will also create this problem. The vacume advance on the C-4 is for shifting from one gear to another when you accelerate hard. It may not be the issue.

Good luck!

Chris-
 
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