Out of Place

[cherryelky305]

I know this is the chevelle section but i need someone who knows older engines and there are not very many people in the el camino section.

I gave my 80 el camino some peddle when i was driving it and now the idle is lower and the engine runs rough as i climb the rpm band. I checked the plugs, because it seemed like a misfire to me, but i guess it isnt. any ideas?

[highlandlake]

Perhaps the carb gasket or intake manifold is leaking?
Loose or cracked vacuum hose?

[capriceowns]

Maybe the idle just needs turned up?

[bobss396]

It could be anything, make sure all the wires are tight on the spark plugs and in the distributor cap. Check for burned wires as well. If it continues to be a miss, you can pull off one spark plug wire at a time to find which cylinder it is. Use a plug wire tool or wear insulated gloves, 60k volts is painful.

Bob

[capriceowns]

Originally Posted by bobss396

It could be anything, make sure all the wires are tight on the spark plugs and in the distributor cap. Check for burned wires as well. If it continues to be a miss, you can pull off one spark plug wire at a time to find which cylinder it is. Use a plug wire tool or wear insulated gloves, 60k volts is painful.

Bob

I found that out the hard way, I had almost the exact same problem with my caprice after I re did my Q-jet it worked great for a couple of weeks, then starting having dead cylinders at idle, so my dad told me take wires off like you said, but left the glove item out, lol.

I found that my base gasket, that goes between the carb and intake was leaking, the kit i got wasnt very good, the gasket was 2 pieces glue together as it got hot the glue oozed out and make a leak.

[rhandwor]

As the engine is running spray carb cleaner along the intake manifold if the idle smooths out replace the gasket. Spray around the base of the carb if smooths out replace gasket. Use vise grips and pinch off hose to vacuum booster. If runs much better get a rebuilt unit. Clean pcv and hoses from carb.
To check timing chain rotate engine counter clockwise to top dead center. Pull the dist cap and mark rotor and dist base with white out where they meet. Turn the engine clockwise with a person watching the rotor. Stop when the rotor starts to move. Over 15 to 20 degrees you need a new timing chain.
If the chain is good retime the engine. Check that the vacuum advance advances the timing first. Then you need to plug the hose to the vacuum advance to time the engine.
I would inspect the cap and rotor and ohm all plug wires while I was working on it.
You may also need to install a carb kit.
A worn valve guide and camshaft will cause a mis and also backfire.

[ACLineman]

All good suggestion here.

Could it have been tuned (the idle & airflow jet set) with the engine cold and the choke pull off not at operating temp?

I know on my 69, 396, when I press it to the floor(to set the choke) and start it it runs at a higher RPM until the choke releses. If I try to drive it before the choke pulls off it runs like crap until it reaches higher RPM's.

All tuning of the carb should be done after the the choke is out of the picture and the car is warm.

What engine is it?

[cherryelky305]

Its nothing fancy, just the ol' 305 but none of that emissions stuff is on it and its got an aftermarket carb. Three speed tranny. Yeah I just gave it some gas, after i had been driving it a while so it was warm, and then when i stopped at the next stop sign the rpm's had dropped and it was running rougher. Maby im getting used to it but it seems to have subsided. I have no idea whats going on with it. Its a work in progress and its 26 years old, so its time to start fixing things. Funny thing when i had brake work done i found out that the brakes on it were the original factory brakes, They hadent even been adjusted, so needless to say that was $482 to fix.