Half my engine is not firing... I'm stumped

This has been great feedback and we are making progress!
This can now be recassified as a carb problem. The engine not getting fuel through one side of the carb made alot of since and I think I confirmed it. I tried to see if the engine would run on only 2,3,5,8 (the previously assumed "bad" cylinders; I had not tried this yet) and it ran! BUT only if I kept giving gas. It would not idle at all on these cylinders. Good news is that I have no engine /dist problem. The problem: The reality of the situation is that at idle, I am only running on four cylinders, when I give gas, all eight are firing. I turned out the idle mixture screw on the driver side all the way (to try to get 2,3,5,8 to idle), but there was no change.
So what is preventing one side from giving gas at idle? Are there any other carb adjustments that I should play with?
Thanks again for all the help!

 

If you take the front bowl and metering block off the carb look for a plugged idle feed restriction. It is in the metering block on the main body side. About one inch out on either side from the center of the power valve you will see a small rectangular hole. It will have a brass plug with a small hole drilled in it(this is the idle feed restriction). Make sure it is clear. Also check the main jet on the side thats messing up. It would not hurt to blow out all the passeges and holes in the metering block and carb body. Also check the throttle plate gasket to be sure the hole for idle fuel is not blocked as well as the passage in the throttle body

 

Yup, it's an idle feed problem.

Nice threadjack, Scooper.

 

Hey, I thought it was a good place for that question...

I get a little tangential at times. Probably because I work with ADHD kids all day long...OOOPS! I just tangented again!

Sorry, I will try to do better from now on. Just stop me if I get out of hand.

 

my son is ADHD.......and he does that lot...oh crap here i am goin way off topic....

 

My brother farted in a coke bottle once and tricked me into smelling it. Man, I hated that.

Please keep us updated with the carb fix.

 

Problem pretty much solved.

Beind inexperienced with carbs, I had to educate myself before I got stared. I read a carb book and then took to the problem. As was suggested, I took off the front bowl and metering block and sprayed carb cleaner through all the idle passages. Put it back together and still it didn't run right.
Then I realized that it was a vaccum problem. I had the vaccum port labled "full manifold vaccum port (power break or pvc)" (pic1) hooked up to the connector on the valve cover neck (pic 2). The channel on the bottom of the carb that feeds this vac port comes off the bottom of the driver side primary! That explains the symptoms (I think). The port is getting unrestricted flow and diluting all the fuel gong into that primary. Right now I have the hose to the vac port plugged and nothing hooked to the oil filler neck port. Its running nicely. But now I do not know how to make this connection to the valve cover. Is there a filter that restricts flow that should be there? Was I not supposed to make that connection at all? BTW the valve covers are the kind that came on 5.0's with a baffel at the bottom of that fill neck. Thanks! Dan

 

That hole in the valve cover is where the PCV valve is supposed to go. It still opens up to vent crankcase pressure, so not sure if it would still act up in your situation. Strange.

 

That port on the carb does hook to your valve cover but you should have a PCV valve on the other end of the hose not just an open vacuum, it will not work as is with those valve covers. The later model fuel injected cars had the PCV valve that plugged under the back of the intake and not in the valve cover. If you could drill a 1 inch diameter hole in one of the valve covers and then put a rubber grommet in it then your PCV valve could go into the grommet and then your hose from the carb. Then just plug off the pipe coming from the filler neck, unless you can find an inline type PCV valve.

 

Sorry, this is a mistake, its the driver side secondary. This would still have the same effect of rushing air into the driver side of the intake manifold thats not comming through the carb.

 

If I am seeing the picture of the carb right, the fitting you have circled is the air inlet for the electric choke and no hose goes there, the PVC fitting should be on the backside of the carb on the base plate.
Clint

 

To make things easier, is there any sort of inline pvc valve that I can put between the carb and the filler neck?
Also, I see that the old style covers has holes in both valve covers. Do I need to puch a hole in the other side as well?

 

Clint,

I'm not sure how you mean. A hose certainly fits there and the holley installation manual lables it "full manifold vaccum port (power break or pvc)" I dont have a plate between the carb and intake either.

 

I think they make a pcv valve that would splice into a hose. If they don't, Im sure you could rig something up. Yes the other valve cover needs a hole in it. The air that is pulled out by the pcv is drawn in through the opposite valve cover. You would need a breather on the other valve cover, or a hose connected to the air cleaner.