i have a olds 455 in my trans am i pulled it out to paint it put some new chrome on it new oil pan ... anyway, i put it back in never took the distributor out never moved it nothing,,, all i did was take the 800 double pumper off cuz it was leaking the base plate was cracked and what not anyway,,, i put a 670 street avenger on just to let the motor run but damn the motor is running the **** its backfiring through the carb, the plugs are telling me its running rich they are dry black and sooty, the plug wires are all in the right spot and i never pulled the distributor it ran pretty good be4 i pulled it? any ideas guys? i did pull the one head to see if it was bored but i mean i put it back on right and torqued the rocker arm bolts back to 25 ft lbs

 

Guess #1: Plug wires.

- Eric

 

i got a firing diagram offline made sure i routed them right i triple checked them they are routed right

 

Right for a distributor that turns counter-clockwise?

- Eric

 

yes sir that was the diagram i got offline

 

Hmmmm... Okay.

And it's not 180° out of sync.? (remember TDC for #1 can be compression for #1 or #7)

- Eric

 

And you're sure that the new carb doesn't have a stuck float or needle valve, right?

- Eric

 

i don't believe so i mean i never moved it when i pulled the motor and it was fine be4 i pulled it i was thinking it has more to do with the small carb i put on but im not sure....how do i tell if its 180 out? right now its pointing at number one on tdc compression but there was a few diff diagrams that showed the number one was towards the back of the distributor then the one i had that shows the number one plug wire is in front of the distributor

 

and yes positive on the no stuck float or needle valve the carbs not even 3 months old

 

Wherever the #1 wire is connected, the rotor should point to that terminal when #1 is at TDC on its compression stroke.

- Eric

 

We've had examples of new carbs with stuck floats on this board, so be careful.

- Eric

 

ya thats how it is its pointing at number one tdc compression i haven't timed it yet but i don't see how it coulda got out of time if i never pulled the distributor

 

i have had the float bowls apart be4 to change jets put bigger ones in and it made it worse it would just choke its self out with to much fuel

 

I agree, it shouldn't have.

Any chance you've got a bad ignition component - module, pickup, etc.?

This is one of those problems where you're going to have to go very slowly, step by step, and re-check everything, until you find the one obvious problem.

- Eric

 

idk unless the coil went bad on it

 

I'm thinking the same as MDchanic as it's something ignition related. Something simple like a cracked or worn distributor cap/rotor, frayed or shorting coil wires, or malfunctioning electronic ignition.

 

Might the motor have a larger cam, not pulling enough vacuum for that carb??