5.4L gas engine - Diesel Forum

Paul338 · 12-15-2002, 07:15 AM

I have developed a dead miss in the engine that exists at all speeds. I'm sure one cylinder is dead. How can I determine which one it is with out any test equipment other than a multimeter. It has the coil pac ignition so there are no9 spark plug wires to remove or check with test light.

Paul

monsta · 12-16-2002, 09:41 PM

Why can't you remove the wire going to the coil pack until you find the one that doesn't alter the miss?

Wonder why the check engine light isn't coming on for a miss? [img]/ubbthreads/images/graemlins/shrug.gif[/img]

HARDCOREFORD · 12-18-2002, 03:56 PM

strange but true, if a coil pack is not working on a certin plug
most of the time if you find the bad, or dead hole, and swap it with
another from a different location, it will work. as to the best way to
find the bad location, try the old unplug trick, when it runs the same with the coil pack unpluged, you found the problem. good luck!

guss · 12-31-2002, 09:40 PM

i was told you dont want to unplug wile running or you can burn them up that way.

akrewat · 01-01-2003, 01:19 AM

Yes, you don't want to unplug high-output outputs from the computer
while it's running [img]/ubbthreads/images/graemlins/smile.gif[/img]

4Tfords · 01-06-2003, 05:25 PM

Why don't you get the truck warm or hot .shut down and pull the coil pack and do a ohm /resistance chk ,look for one that that is different than the others. at the same time pull the plug ,look for different color!
[img]/ubbthreads/images/graemlins/shrug.gif[/img] Rich

TMace · 01-12-2003, 02:05 PM

Warm the engine then shut it down. Feel each spark plug or around the exhaust port. You should be able to tell which one is not firing by the temp difference. Be carefull, you do not want to leave your hand there to long.
P.S. I carry a 12 v test light with that is capable of checking this. It is a heavy duty one from Snap-on that has a point on the probe similar to an ice pick. Just connect the ground and pierce the spark plug boot with the tip, enough to ground out the cylinder. Listen for the engine miss to either get worse or not change. When you get to the one that has no chage you've found it. After your done put a small dab of RTV over the hole you created.