Old trick, forgot the details

ghreds · #1 (**permalink**) 05-07-2008, 06:28 PM

I used to know a trick on finding a dead miss. You take the spark plug wires off one at a time and put the wire back on, but not all the way, leave the connector just barely off the spark plug. When the idle smooths out, you found which cylinder is the problem. I found that when I do this to my #1 cylinder, the idle smooths out considerably. Problem is, I can't remember what that means or what's wrong. Anybody heard of this old trick?
I realize that you can just pull each plug completely off to find which cylinder is missing, but it really smooths out when I have the plug wire barely off the plug.

Milwaukee1979F150 · #2 (**permalink**) 05-07-2008, 07:06 PM

How you manage without shock it?

I have did that. It need to have 1 real dead cylinder then unplug spark plug on good one it would shake like ready to stall.

hard to say with those engine since I did was on my Ford tractor with 4 cylinders but those sure have good spark that enough jolt you every 2 to 3 sec but I didn't know until feel weird why sting in my finger until saw spark wire in my finger that was 6 sec hold those.

Kruse · #3 (**permalink**) 05-07-2008, 07:09 PM

Quote:

Originally Posted by ghreds

I but it really smooths out when I have the plug wire barely off the plug.

How old of a vehicle is this?

Call me stupid, but check to make sure you don't have a carbon track inside your distributor cap. Sometimes if the cap is bad, the vehicle will run better with one plug wire completely pulled off.

fmc400 · #4 (**permalink**) 05-07-2008, 08:14 PM

I think you need to check your plug gap. I will also second what Kruse said.

ghreds · #5 (**permalink**) 05-07-2008, 08:37 PM

Milwaukee1979f150, I try to make it a habit to never touch the wires when it's running. Use a pair of needle nose with some rubber grips or something like that. Sorry, I guess I should have been more specific about that.

Anyway, I guess it means you have a fouled plug. I changed the plugs and it runs great. Works for me. Y'all might want to try it next time you have a miss.

85e150six4mtod · #6 (**permalink**) 05-08-2008, 01:00 AM

They make some "Chicken Pliers" for pulling plug boots. Round shape at the end, Plastic coated top and bottom. They make you think you can pull the plugs w/o shock. After you pull a couple w/o incident, you forget the wires themselves with throw one at you and you cut your hand on the ac mount and bang your head on the hood, which, if held up by a strut, comes off the strut and smacks you again. Not sure how I know this as it's never happened to me that exact way.

Tom92F150 · #7 (**permalink**) 05-08-2008, 05:41 PM

From what my Grandpa's told me when he does this, the extra gap in the circuit makes the spark hotter and the plug more able to fire if fouled. If your engine smooths out like you're saying, it could mean that the idle is a little rich. But then aren't #1 and 6 supposed to be leaner being furthest from the carb? Or is it the other way around?

It could also mean that oil is getting in the combustion chamber and fouling the plug. Maybe past the rings or the intake valve seal. What weight oil are you currently running? Does the engine use any? You could try the next heavier grade on your next oil change. Shouldn't hurt anything in any case.

There used to be little spacer adapter things that you could screw into the head and then screw your spark plug into essentially making a precombustion chamber. They were supposed to help prevent plug fouling from what I understand. I don't know if you can still get them or not, but it seems to me that they only treat the symptoms and not the ailment.

Anyway, if your new plugs foul up again (and I'd say it a distinct possibility), I don't really know how to tell if its oil or gas thats causing it. Maybe someone else does?

OldMetal · #8 (**permalink**) 05-11-2008, 02:27 PM

Quote:

Originally Posted by ghreds

Milwaukee1979f150, I try to make it a habit to never touch the wires when it's running. Use a pair of needle nose with some rubber grips or something like that. Sorry, I guess I should have been more specific about that.

Anyway, I guess it means you have a fouled plug. I changed the plugs and it runs great. Works for me. Y'all might want to try it next time you have a miss.

Yes, what you learned here is that with a wire pulled off the coil will increase voltage to bridge the gap and will sometimes cause a weak plug to fire.
Some plugs were/are made with a internal gap to increase voltage.