So fun story/question for you 5.4l experts. 120k on my truck. Full bolt on and tuned from day one.

Heading to an out of town job 148 miles away. about 18 miles from the job site. going up a 7% grade passing a semi, WOT, 85mph and accelerating. All the sudden feels like a missfire, and started loosing power. Looked in the passenger side mirror and looks like im dumping unburnt fuel. Before I had time to react BOOM! flame ball and sparks the size of a house comes belting out of my side exit exhaust, completely engulfing the semi! (probably made him crap his pants) Still running like I had a bad missfire as I pull over. Soon as I come to a complete stop dash flashes transmission failure and Low oil pressure then the motor dies.

So knowing its not moving again I was just curious and cranked it over cranked fine and actually wanted to start again chugged once and died. Tried again same thing chugged once and died. So I called a co-worker and put a note in the window for Highway PD (tow truck en-route name # etc) Went to work. after work about 9 hours later I show up to wait for the tow truck. I decided to investigate as I had 2-3 hours to kill until they show up. Pulled plug #2 stuck a bore scope down the hole and looked good plug pristine (changed 20k ago with coil packs) Having recently been 4 wheeling I didn't pull anymore plugs until I get home as you guys know the spark plug design with dirt falling in unless cleaned with compressed air I gave up on checking for damage in the cylinders.

Found dip stick 4 inches popped out with a lil bit of oil sprayed out (i'm guessing massive blowby)

Go to the exhaust and find Melted chunks of cat honeycomb.

Just a clogged cat got the best of me and just needs to be cleared? if the exhaust was clogged could it harm the motor with all that excess pressure?

Was this caused by timing chain breaking or cam phasors? I've never replaced them but didn't feel I needed to because no ticking and the motor was strong and made beautiful V8 noises nothing abnormal. can't work on it till this weekend but what are you guys thinking? It toast? should I start looking at new 5.0's? I'd like to savage it cuz that truck has been the best truck i've ever owned. Very sentimental about it and I almost feel like I lost a family member haha.

Thoughts? Recommendations? My truck FUBAR? Any similar experiences?

Thanks

Pic of my beautiful truck a DAY before the accident out deer hunting and some pieces of cat I found in my tail pipe.

 

I have heard of fuel pressure regulators failing, sucking raw fuel into the vacuum system and an explosion results. A possibility. A failing CAT would have given very noticable symptoms well prior to the explosion and would not have caused this. I think the melted CAT is a victim of something else terribly going bad.

 

Look at bank 1 injectors.. (looked like dumping raw fuel passenger side mirror).

 

Well figured it out, Coil pack shorted out. Causing it to blow the ignition fuse and the ignition driver in the ECM on cylinder #3. It fired back up because the other cylinders were fine. I pulled the ECM apart and found the driver and a few resistors scorched. Unfortunately not something I can find at the electronics store. So I need a new ECM. Hopefully it isn't too pricey or I can get one from a junk yard.

 

J/Y ECM, make sure to match calibrations. Might have to go to a dealer and get something re-flashed if it's different.

 

What coil packs are you using? Unless they're FOMOCO, I'd be hesitant to put it back together with a new ECM.

 

Actually went and got bran new OEM coils and plugs. Just to be on the save side, even though i did it 20k ago. This will be the last time I use aftermarket coils.

 

Ordered the actual part number and gave them my vin, to get a remanufactured one. 200 bucks. so not bad. I'll still have to do a compression test when i'm done to make sure it didn't kill the rings but otherwise even if it is tired i'll fix it. New trucks are too expensive to go wheeling and run down trees scrape through tight trails etc.

 

Yeah I've heard bad things about aftermarket coils. Good luck! Hopefully it didn't do anything too major. You'll for sure need to either replace the cat/cats, or just finish clearing them out and call it a day.

Not bad. And I definitely agree, I pulled some pinstriping (should buff out) from a trip I took in mine. I figure at the end of the day it's a truck and is made to be used as such, granted this trip it was used more like a Jeep. Haha. Literally there were 3 trucks there and the rest was all Jeeps. My '07 definitely got abused as well, WAY harder than this truck has so far. Covered the '07 in mud a few times goofing off with friends.