Welcome to, The home of the PCCA => General Help- Ask the Experts... => Topic started by: onebadcaballero on August 03, 2015, 10:28:13 AM

Title: Bad Bog
Post by: onebadcaballero on August 03, 2015, 10:28:13 AM
Hey guys. I bought a 76 Pinto Pony MPG about 6 months ago. It's the sedan model with the 2.3 and 4 speed. First thing I did was plugs, cap, rotor and wires and that seemed to smooth it out but it still wasn't quite right. As you could imaging the with its age it had some vacuum leaks. I removed the egr using a brass plug on the exhaust manifold and fabed up an egr block off plate using 18 gauge sheet and used rtv to seal it. I then used two brass plugs with teflon tape for the vacuum ports on the intake manifold and re-did the line for the pcv valve. I replaced the distributor also since the vacuum advance diaphragm was blown and the mechanical advance was very loose and sloppy. I set the initial timing at 10 degrees rather then the factory specified 6 since it seemed to run a little smoother there. Then the trouble starts......

I decided to rebuild the carb (which was also loose on the manifold). I've had some experience with various holley 4 barrels but this was my first 2 barrel.  I took the carb down to the main body and soaked it in purple power for about two hours and shot all the ports out with carb cleaner. When I put it back together I replaced the power enrichment valve with the one in the kit, as well as the accelerator pump diaphragm, but reused the original needle and seat assembly since it still worked like a charm. I've always liked dechoking carbs so I left the choke assembly of as well as the butterfly valves at the top of the carb. I used JB weld to plug the vaccum port where it would normally have operated the choke. I left the float height as I found it because all of the literature I could find referring to the float height showed a boxy black plastic style float where mine is the rounded brass style.

So I buttoned up the carb and hooked everything back up. I know have only 1 vacuum line (the carb going to the advance), the pcv going to the plate between the carb and the manifold and the breather hooked up to the air cleaner. The car's running ok but there is a really bad bog/dead spot between about 1/8 and 3/8 throttle. I checked the accelerator pump and its giving a nice strong squirt. I set the idle mixture screw for the smoothest idle. Something I strange i noticed though is if i fully tighten the primary idle jet screw it wont run. If I back it out half a turn or anything further it runs as described. What's going on?
Title: Re: Bad Bog
Post by: TIGGER on August 03, 2015, 08:15:14 PM
Have you checked the diaphragm on the advance unit to see if it is any good?  That is the only thing that comes to mind at the moment.
Title: Re: Bad Bog
Post by: onebadcaballero on August 04, 2015, 01:24:24 PM
The new distributor came with a vacuum advance module. The old distributors advance diaphragm was torn. The new one is good. Thanks for the reply.