I was offered a 2005 TB with the 4.2 engine. The car has at least one known problem- somebody replaced the spark plug of cylinder # 5 incorrectly, and probably damaged the threads. Also, the bolt of the coil of the same cylinder is broken. They "repaired" the car somehow, by fabricating an aluminum "bridge" between the coils # 4 and 6 to fix the coil # 5 in place. The car starts but the engine runs with a misfire. The owner stopped to use this car several months ago and now he wants to sell it. We checked the misfire data; there are multiple (about 40-50 in one minute) misfires in cylinder # 4 (not 5!). I am thinking about buying this car. I think I can remove and repair the broken coil and the plug together with my friend. I will extract the broken bolt and use a Heli-coil to repair the threads of the plug. However, I afraid that even after fixing, there are some chances that the engine will misfire. The truck has the LPG (propane) setup installed on it. The LPG itself is known to cause the excessive wear of the valves. What do you think, guys, what are the chances that the engine is screwed up?
2005 TB plug is stuck, misfire
- Thread starter santon
- Start date
Mooseman
Moderator
It could just need new plugs, especially if he used non-ACDelco parts. Could also just need some new coils. Some have had good luck with cheap sets from Amazon.
The LPG does throw another variable that I'm not familiar with. It might be a good thing especially with the high gas prices.
If the price is right, I'd take a shot at it.
The LPG does throw another variable that I'm not familiar with. It might be a good thing especially with the high gas prices.
If the price is right, I'd take a shot at it.
Of course, I am planning to replace the plugs and, maybe, some coils. It seems that he used non-original coils.
Here the majority of TBs have the LPG setups installed. While it provides the great economy, the LPG seems to have some problems. As I understand, the propane has the higher burn temperature than the gasoline. This may (or may not) lead to some problems with the valves and compression. So, I am not sure whether the misfire in this truck was not caused by the damage of the engine by LPG.
They say that the propane is much cleaner than gasoline. Some people driving in propane for quite a long time and don't experience any problems.
If the problem with the Coil Over Plug (COP) is that the Threaded Portion has snapped off inside of that Tiny "Hole In The Head"... @Sparky once suggested using a Dental Pick to carefully back out the the threaded remainder, realizing that after the bolt is broken...it is under NO LOAD and should yield to gentle persuasion for removal.
However... if the Problem involves the inner thread lines being Completely Stripped Out... know that I've penned (and performed) a solid repair of this issue using a Time-Sert Kit for the M6 X 1 X 12mm STI (Screw Thread Insert) Sert Installation as well documented in THIS "How To" Thread:
gmtnation.com
THIS is the Time-Sert M6 X 1mm X 12mm Repair Kit you will require:
THIS is a Less Expensive, Heli-Coil Like Repair Kit (Made in USA):
However... if the Problem involves the inner thread lines being Completely Stripped Out... know that I've penned (and performed) a solid repair of this issue using a Time-Sert Kit for the M6 X 1 X 12mm STI (Screw Thread Insert) Sert Installation as well documented in THIS "How To" Thread:
How to Repair Stripped Out 'Coil On Plug' Fasteners:
How to Repair Stripped Out COP Fasteners: If you make the mistake of “Honking Down” Too Hard on the Coil On Plugs Hold-Down Fasteners with anything more than 87 INCH Pounds of Torque… One of Two Bad things will very likely happen: (A) The Hold Down Bolt will Snap Off close to the Top of the...
gmtnation.com
THIS is the Time-Sert M6 X 1mm X 12mm Repair Kit you will require:
THIS is a Less Expensive, Heli-Coil Like Repair Kit (Made in USA):
M6 x 1.0 Metric Thread Repair Insert Kit Perma Coil 1221-306 6MM Fits Heli USA | eBay
PERMA COIL. OUR STAINLESS INSERTS ARE 50% STRONGER THAN THE ORIGINAL THREAD. KIT CONTAINS TAP, INSTALL TOOL, GUIDE AND 12 INSERTS. FITS MODEL. MADE IN USA. MOST HAND TOOLS ARE FULLY COVERED BY MANUFACTURER UNLESS OTHERWISE STATED.
www.ebay.com
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Do you guys think that I need to remove the valve cover in order to extract the broken coil pack bolt, #5 coil?
In a word... "Yes."
In another describing the problem.... "Access"
In a Photo showing these physical restrictions preventing access and room enough to work on the problem... either using a Dental Pick to Un-Screw the Broken Off M6X1X12mm Bolt Shank... or if necessary, to employ the Excellent Time-Sert Method if the Threads in the Head have been Completely Destroyed:
...and finally, the problem of access is well illustrated in the VOP's (Video Original Poster) Dramatic Valve Cover R&R Video emphasizing these actions as being... necessary:
In another describing the problem.... "Access"
In a Photo showing these physical restrictions preventing access and room enough to work on the problem... either using a Dental Pick to Un-Screw the Broken Off M6X1X12mm Bolt Shank... or if necessary, to employ the Excellent Time-Sert Method if the Threads in the Head have been Completely Destroyed:
...and finally, the problem of access is well illustrated in the VOP's (Video Original Poster) Dramatic Valve Cover R&R Video emphasizing these actions as being... necessary:
...and of course... with all of THAT Strenuous Activity out of the way...You'll finally have enough room to work. It will be important to Cover Up the adjacent Open Spaces around the Camshafts and Bearing positions completely with "Blue" Scott (Low Lint) Shop Towels.
This will prevent contaminating the Upper Engine Head either with Aluminum Swarf (or a dropped Broken Bolt Remnant) from either having to Drill Out the COP Broken Bolt remainder if it cannot be coaxed loose with a Dental Pick... or if using the Time Sert Method becomes the only solution to the problem. Remember to Stuff the Spark Plug Holes with the "Blue" Scott Shop Towels as well...for the very same reasons:
This will prevent contaminating the Upper Engine Head either with Aluminum Swarf (or a dropped Broken Bolt Remnant) from either having to Drill Out the COP Broken Bolt remainder if it cannot be coaxed loose with a Dental Pick... or if using the Time Sert Method becomes the only solution to the problem. Remember to Stuff the Spark Plug Holes with the "Blue" Scott Shop Towels as well...for the very same reasons: