Manic Monday

pell

Original poster
Member
Jun 5, 2017
88
Pelham, NH
So my TB was running great yesterday. Changed the oil drove fine. This morning took out for a drive engine light flashing poor response from throttle little misfire-coil pack maybe? Plugged in my code scanner nothing, will not light up. Tried in another vehicle scanner works fine. Any ideas? Thanks Greg
 

christo829

Member
Dec 7, 2011
497
Fairfax, Virginia
If the scanner won't light up, check fuse 13 (CIG). That passes power for the OBDII port and cigarette lighter. Hopefully that will get your scanner working so you can diagnose the rest. EDIT: That's the under hood fuse box, btw...
 
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TollKeeper

Supporting Donor
Member
Dec 3, 2011
8,047
Brighton, CO
If your scanner has a live feed function, try to find the misfire counter. A P0300 means its still trying to determine which cylinder is missing.

Or give it a tune up as a starter, sometimes a fouled/wet plug can also tell you which plug.

Once you find out which cylinder it is, you will need to determine if its a bad plug, plug wire, or a bad coil. If its Cylinder 4/5, its a fairly common problem to have a bad coil on the cylinder.
 
Dec 5, 2011
574
Central Pennsylvania
Obvious things to check: are any coil packs unplugged? Were any sensors unplugged? Any hoses removed and not replaced? - including the few vacuum lines there are?

More troubleshooting:
Clean the throttlebody if not recently done.
To troubleshoot the misfire specifically: remove air tube to get access to coil packs. Start vehicle and unplug one coil pack at a time. If there is no change in the idle - that's a suspect cylinder. If the idle gets worse, that's a normally functioning cylinder, plug it back in. Once you've identified the suspect cylinder(s), swap the coils (but not the plugs) to known good cylinders and start over. If the misfire follows the coil, it's the coil. If the misfire stays with the cylinder it's either the spark plug or the wiring to the coil.
Also, when was the last spark plug change (at most 100k miles)? Are the plugs correct, ACDelco 41-103, and verified genuine? Genuine 41-103 spark plugs do not need gapped, they are gapped from the factory. Also, clean the spark guide (the spring between the coil pack and the spark plug) if there's any "schmutz" on it. If you notice any fluid around a spark plug, soak it up with a towel (paper or otherwise) before doing anything else. Apply dielectric grease or petroleum jelly to the coil pack gasket before reinstalling to help prevent water from entering the plug well. It is not uncommon - but not desired, either - for there to be oil in a plug well. If it's excessive, you may want to replace all of the gaskets in the valve cover - 1 outer perimeter gasket and 6 plug well gaskets.
 

pell

Original poster
Member
Jun 5, 2017
88
Pelham, NH
Looking at threads here for the code and reading about the rain going into the hood cowling then onto the #4 cylinder coil pack I believe his might be the issue. Sunday night in my area there was an intense wind storm with driving rain. It was an Auntie M type storm, Toto would have been in the storm cellar. I recently replaced all the plugs, thinking maybe I did not set the boot correctly. Ordered a couple of coil packs. When time allows will check it out. Thanks for all your help.
 

KEEBZ489

Member
Jan 16, 2018
245
Howard Beach NY
did you use the correct plugs? also what coils did you get ? the ets of 6 from places like amazon ? i cheaped out and did that too. 1 was bad in a day , 2nd took about a month. it is best to get a scanner to see what cylinder it is. $20 for an obd wifi / bluetooth to use with your phone will go a long way now and for the future
 

pell

Original poster
Member
Jun 5, 2017
88
Pelham, NH
Finally had time to get under the hood. Started with #4, water in plug well, wet boot. White Ring around the boot where it meets the head. Replaced the coil pak. Still miss firing. Did #5 seemed Ok no water, replaced coil pak. Still bad went to #3, looked OK replaced anyways. #2 had so much water in there could not see the metal part of plug. Replace coil pak. Still bad. Did #1 moisture on boot, plug well seeemed OK. Running good now, Thanks Guys for help. Found oil under the TB leaking.Replacing the sensor above the oil filter, never a dull mommet with this velhicle.
 

pell

Original poster
Member
Jun 5, 2017
88
Pelham, NH
Tequila Warrior suggested "Apply dielectric grease or petroleum jelly to the coil pack gasket before reinstalling to help prevent water from entering the plug well". Why not just use RTV silicon instead? This seems like a common problem and it seems like any time during a rain storm this vehicle could fail and me stranded.
 

bfairweath

Member
Oct 20, 2013
95
Neenah, WI
The prevailing wisdom is that #4 gets water in it from a bad hood seal on trucks that are stored outside. I wonder how you're getting water all the way up to #2 unless it's running along the inside of the hood. See any evidence of that? Take a look at the hood seal and repair or you're going to have the same problem again.
 

pell

Original poster
Member
Jun 5, 2017
88
Pelham, NH
Found an old thread about this. The TSB#06-06-04-048B states that this could happen to any cylinder. Also posted was a way to fix it with Frost King weather stripping. On my way to home depot.
 

pell

Original poster
Member
Jun 5, 2017
88
Pelham, NH
So this is now ground hog day. Another storm comes thru on Sunday night. Although I got the goods to work on the hood cowling I did not have time to address the problem. Left this morning in the pouring rain in my service truck and was in it working until it stopped around 3 pm. Finished around 6:30 got home checked the TB. See the attached pics of the a flooded valve cover. Blew it out with compressed air and heat gun. I have not run it, going to pull the coil packs and try to see if they can be saved.
 

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