rough idle

[davidrodriguez6769]

New plugs,wires,timed and still rough at idle. Any ideas guys? 360 motor ,rebuilt carb also didnt help.

[Josh D]

Checked for vacuum leaks? Have you pulled each plug wire while running to find what cylinder isn't firing at idle? Have you adjusted idle mixture on both sides of the carb? How many miles on motor? High mileage could indicate a flat cam lobe or two or possibly a burnt exhaust valve.

[davidrodriguez6769]

Its got 80k miles, all cylinders are firing,carb is adjusted,maybe need a new dizzy cap. PO removed all smog equipment so I'm not sure about vacuum routing.
Is there a schematic of the system with no smog equipment somewhere?

[shaolinsifu]

sounds like vacuum, did you gap the plugs before installation? Don't trust 'em out of the box!!

[davidrodriguez6769]

Yes I gapped the plugs,it must be a vacuum problem

[badaboom]

Fuel pressure, fuel pump - fuel filter just a guess.
It seems like you have done everything else.
These vehicles love fuel.

I love the smell of octane in the morning.

[davidrodriguez6769]

yes, just replaced the fuel pump 2 months ago and also the filter at the same time. I guess I'll just have to try and figure out the vacuum system , cant be that hard. Thanks for the input

[joe]

When you rebuilt the carb did that include a new/correct power valve?

[86j10]

i'd be willing to bet if you rebuilt the carb and didn't replace the power valve thats ur culprit. i'm in need to replace mine this weekend as this is whats causing my rough idle after i just recently replaced my cap/rotor/plugs/wires. if not then i'd lean to the vaccum

[davidrodriguez6769]

It has a holly 2bbl carb on it and the rebuild kit did come with a power valve. the kit was a holly one size fits all from autozone,it covers 2 and 4 bbl carbs. is there a difference in power valves or are they universal?

[Josh D]

They are different and based on manifold vacuum. My 360's with Holleys seem to like a 6.5 PV iirc.

[davidrodriguez6769]

were can I pick one up at or will I have to buy a new proper kit? thanks

[tgreese]

Stuck EGR valve? Carbon will hold the valve open at idle, when it should be closed. Common problem that causes a rough idle.

Get a new gasket, remove the valve and wire brush the pintle clean. Reinstall.

[davidrodriguez6769]

thanks , sorry about having 2 post going didnt mean to

[[]V[]AXX]

Hey, I just installed my P.O.S. Carter BBD on my six banger in my 79. The carbs are set for real gas, not this ethanol laced garbage we're getting now. I had to crank out my idle mixture screws three full turns from stock settings to enrich the mixture enough to make it idle decent. Then, when you put any kind of load on the engine, you'll find that it likes it a little richer still. I went another half turn, and it seems good now. Now they're lobbying for E15 to be the standard, as if this E10 wasn't bad enough...