Hey guys

When I swapped out my old and bad Accel ignition wires for my new MSD the engine kept firing one or two cylinders after I turned the ignition off.
I guess I can fix this by doing something to the Mallory distributor but what and how?

Help is very much appreciated.

Thanks!

Regards

Anders

 

What is your timing set at?

 

Chances are it has nothing to do with the ignition.

It's called "run on", caused by deposits, high idle, overall improper tune or a combination thereof.

IMO you're wasting your time and money on replacing parts at this point.

 

Carbon build up is probably the cause of the problem like cutlassefi said.

IMHO get your self some Sea Foam or a spray bottle of water and do an old fashion carbon build up removal.

 

70 cutlass s, I don't know. I'm a V8 newbie so go easy

cutlassfi, I put on a new carburator since the old one was in pretty bad shape. So getting this calibrated might stop my problem? Idle is about 900 RPMs. Thats pretty high right?
I do not wish to buy any parts at this point

1966_F85, Carbon removal? Newbie, sorry

Thanks for you replies guys! Very much appreciated!

Cheers

 

It can also be from bad/low octane gas or timing. Did you change plugs when you changed wires? If they have deposits on them they can create hot spots and ignite the fuel.

 

If it's a stock setup set the idle at 750 or so after correct mixture adjustment. Make sure you have the right heat range plugs in it. Then either pour trans fluid or water SLOWLY down the carb throat while running being careful not to get any in the bowl vents. Rev it every once in awhile. Also make sure the engine temp isn't excessively high as well. Start with that and let us know.

 

It's not going to get at the cause of your problem, but one way to stop the dieseling is to turn the ignition off with the car still in Drive (or Reverse, or some gear), rather than Park, so there is a load on the engine. Then put the car in Park and take out the key.

 

I just started my engine for the first time and was begining to break in my cam when I needed to shut the engine off(oil leak) and I experienced this same problem. I hope I didn't damage my valvetrain because it fell below 1500 rpm for about 2 mins as I was attempting to shut it down(ended up disconnecting power wire from tach). What do you guys think is the problem as everything on my motor is brand new. Plugs, wires, HEI distributor, Carburetor, etc. I did not get to adjust my idle, mixture screws or fiddle with the timing as I was concerned I may have done some damage to the new valvetrain. Plugs are gapped at .40 should I open them up, or maybe back off the timing, or lean out the carb??? Dish out the suggestions experts.....

 

Make sure your throttle return spring is closing the air dams all the way.

 

what does timing have to do with it if the key is off and no fire is coming from the coil?

 

It wouldn't have to do with the coil. It goes back to what Mark was talking about with improper tuning. If the timing wasn't right then the air/fuel mixture more then likely be set wrong as well. Just overall improper tuning. Which the effects have been talked about in this tread. Since reading the replies I didn't see a point to repeat the same info. So I didn't post. Sorry I didn't go into more detail before.

 

I've seen post after post in many different forums when someone in having a problem with dieseling to check the timing. Since the plugs aren't firing it makes no difference what the timing is. The engines of the early 70s era were plagued with the problem. Yes, lean idle mixtures contribute to the problem (those carbs had devices installed to deny access to the mixture screws for emission regulations) as well as carbon build up in the cylinders either raising the cr or leaving hot spots to act as glow plugs as in diesel engines. raising the octane of the fuel and/or lowering the idle speed as little as 25 rpm can make a difference. Some engines were so bad nothing helped except keeping them in gear, using the trans or clutch to kill the engine

 

I believe setting the idle and the air/fuel mixture right should fix this. Shutting the car off in gear solves the problem until then.

I will report back when I, hopefully, have solved my problem.

Thanks guys!

 

Fixed the problem. Set idle lower and adjust air/fuel. Works wonders