Bronco Forum - Full Size Ford Bronco Forum banner

1 - 11 of 11 Posts

·
Registered
Joined
·
973 Posts
Discussion Starter #1
Ok I started a thread a couple of years ago about my 390 in my bronco missing and cutting out. I am still having trouble. When the engine is cold and it pulls hard with the rpms low it sounds like it it hitting on about 5 or 6 cylinders. If you go to a lower gear and raise the rpms it goes away. Once warm it cuts out very slightly on a long hill with low rpms. Once the rpms go up it runs like it should. Here is what I have replaced, plug wires, plugs, control modular, coil, pick up coil, wiring harness from dist to the modular, switch, I have also made the carb a lot richer and replaced the gaskets under the carb. I have done a compression test with engine cold, it ranged from 135-150. The vacuum is 16 at an idle. I dont know what else to chance or check. Could it be the intake leaking? What ever it is gets better once the engine is warm. I have sprayed stating fluid ever where and found a small leak under the carb but replaced the gaskets and now the leak is gone there. I dont know how to check the intake because most of it is under my valve covers. Any ideas would be great. I need it fixed this is my daily driver and camper puller.
 

·
Ultra Premium Member
1996 EB w/5.8 TOO much lift, 44" Mudders & 5:43-5:38's
Joined
·
5,234 Posts
As far as checking for an intake gasket leak on a FE, pull the plugs and look for oil .
 

·
Registered
Joined
·
973 Posts
Discussion Starter #4
The shaft is tight and the plugs all looked great. I changed the plugs at 10000 miles. There was no sign of anything on the plugs. I also changed the battery and added some more grounds from the engine to the frame and from the the battery to the frame.I have tried everything.
 

·
Registered
Joined
·
109 Posts
I see you have an adjustable fuel pressure regulator tucked in there. have you tried lowering the fuel pressure? I had a similar problem once because the electric pump was blowing the needle off the seat and spilling through the vent tube at low RPMs. Once you got it wound up it wasn't noticeable. I also noticed you have and edelbrock or carter. Which side of the carb did you lean out? the primary or secondary? if you only leaned out the front side, i would say you have a lean stumble on the primary and once you open up the secondaries the lean spot goes away because now you are supplying enough fuel to the engine. Also, how did you lean the carb out? just slide some new bigger metering rods in or change jets too?

EDIT: you made the carb richer not leaner. My mistake. Scratch that last part.
 

·
Registered
Joined
·
973 Posts
Discussion Starter #6
I dont have to open up the secondarys to make it smooth out just raise the rpms. It is a 600 edlebrock. The fuel pressure is at 6 psi
 

·
Registered
Joined
·
973 Posts
Discussion Starter #7
I have also checked the voltage at the coil it is 11.5 on the positive side and 6.5 on the negative side, I cant figure out why it only does the bad missing when the engine is cold and not when it is hot
 

·
Ultra Premium Member
1996 EB w/5.8 TOO much lift, 44" Mudders & 5:43-5:38's
Joined
·
5,234 Posts

·
Ultra Premium Member
1996 EB w/5.8 TOO much lift, 44" Mudders & 5:43-5:38's
Joined
·
5,234 Posts
My pleasure. Let me know how you make out.
 
1 - 11 of 11 Posts
Top