running rough

[freddyc]

My sedan is running rough at 1500 to 2000 rpm, 35 mph. Rebuilt dizzy, new plugs, points and carby. Any suggestions appreciated????
regards fred 

[Glenn 'Stinky' Stankevicius]

Check plug and point gaps and that the timing is correct otherwise a Dyno tune, they can replicate what happens on the road an fix it.

[CraigA]

Under light or full load????

Anyway, check that the vacuum and centrifugal advance mechanisms in the dizzy aren't stuck and that the accelerator pump in the carby is squirting a strong jet of fuel. Just because stuff is rebuilt doesn't mean its right.

Check points gap, timing at idle and 2000rpm, and coil output.

Check the fuel pump, filter and system operation.

Stinky is right though, quickest way to find out is on a dyno using an oscilloscope.

[freddyc]

carby points and plugs all working fine, coil is OK to. Will have to Dyno it

[KFH]

When I first got my FC I found that it ran rough about the same revs as yours.  The plugs were new.  I checked everything to no avail.  In the end I held the revs where it ran rough and shorted each plug in turn to see what difference it made.  Every plug except one made a difference to the roughness.  Put an old plug in place of the new one and all was cured.  No noticeable fault could be seen in the plug.  Put it in a different cylinder and produced the fault.

Keith

[fc4me]

Hi before you pay good money for a  dyno tune how about doing a quick compression test and make sure theres no busted head gasket or worse. Hope it helps

[FCGos]

Don't forget to check the spark plug leads also.

[freddyc]

did compression test all 135 psi ???, put coil, leads, plugs out of my other car in still ran rough. Got me and mechanic stuffed.

[fc4me]

Then i'd start looking in the carb  probably around the power valve circuit for a bit of dirt floating around.

[Glenn 'Stinky' Stankevicius]

Carby or Dizzy then  :-\

[EffCee]

Fred,

Change the dizzy, quick simple job and you will know one way or the other.

Just ensure that you have engaged the oil pump when replacing the dizzy

Keith

[wilburwilde]

If a missfire running rough, mabey the valves need adjusting, or one is burnt out.

Will

[collecta]

I would be having the carby o/hauled, if you have swapped electrics from other car as you describe try the carb. You could have a bad vacumn leak at the throttle shaft very common and always rebushed when o/hauled.
cheers
Scott

[fe350chev]

Id do what KFH said, then ulle know if its a fuel or dizzy problem easily. and its quick. a lot would depend if its under load or not

[freddyc]

the carby and dizzy are both overhauled. Am doing inlet exhaust manifold next the looking at dyno and valves etc.

[freddyc]

These problems are 2 different cars.