Random Backfire under moderate to heavy acceleration

SlvrSnake

SlvrSnake

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Ok, anybody have any idea what would be causing a 2005 QC to intermittently backfire under moderate to heavy acceleration when the RPM's climb?

This just started a couple of days ago after a trip to the dealer for trans issues. It has never done this before. They only looked at the trans and determined it has a cracked case. Another story entirely.

I am not getting any CEL's, yet. Is there anything that could have been possibly knocked loose, or is this just a weird coincidence?

I have not a clue what is causing this.

Hmm, am I seeing HEMI sport in my future, maybe. Truck has 38,900 miles on it, acts like it has 238,900. Very frustrating.
 
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Havent had this problem with my 10 but on other vehicles with this issue has sometimes been caused by bad coil pack.
 
Pull your spark plugs, they tell you the condition of your motor. Find a chart like the one below and see what you come up with. Backfire is caused by unburnt fuel igniting in your exhaust system. I see you have a tune, have you tried returning to stock settings and see what happens?

 
Put it back to stock and got same result. Have not pulled any plugs, they have about 20,000 miles on them.

Coil packs and plug wires are still the originals. Would a coil pack be random? Although it is getting worse so as time goes on maybe not so random.

It'll get figured out. Was just seeing if anyone had a problem like this and had the magic bullet I was looking for.
 
BlackMamba50 said:
Pull your spark plugs, they tell you the condition of your motor. Find a chart like the one below and see what you come up with. Backfire is caused by unburnt fuel igniting in your exhaust system. I see you have a tune, have you tried returning to stock settings and see what happens?

Click to expand...

That's pretty high speed that plug chart you got goin on there :D
 
AIT sensor? Mine did that same popping and it turned on light with that sensor as the code.
 
Do you have a catch can or have you done anything with your TB, intake, or valve covers lately? My truck ate about 5 qtrs in one trip to the ocean (about 2 hours). I had just had the valve covers hydro dipped and the wrong PCV vents were put in. Instead of 1 small vent and 1 open vent I had 2 open ones. So the intake was sucking oil right out of the valve cover.
 
I would look at plugs and wires first. Coil packs will normally last longer than 40k. That is a high speed plug chart.
 
Very High Speed Plug Chart Sir!! If you have a bad plug that is not firing at full potential, it could be the culprit. A very reputable Viper tech told me to change plugs every 15k miles, and not to mess with the wires unless you have too, and the coil packs will last longer than the truck itself. ;)
 
VenomTruck said:
Very High Speed Plug Chart Sir!! If you have a bad plug that is not firing at full potential, it could be the culprit. A very reputable Viper tech told me to change plugs every 15k miles, and not to mess with the wires unless you have too, and the coil packs will last longer than the truck itself. ;)
Click to expand...

I googled it!
 
VenomTruck said:
Negative. The correct response would be "yea, I was bored, and tired from alligator hunting, so I made a spark plug chart for the hell of it, took 5 minutes and a shot of Jack"
Click to expand...

Lmfao
 
VenomTruck said:
Very High Speed Plug Chart Sir!! If you have a bad plug that is not firing at full potential, it could be the culprit. A very reputable Viper tech told me to change plugs every 15k miles, and not to mess with the wires unless you have too, and the coil packs will last longer than the truck itself. ;)
Click to expand...

When I changed the plugs I went with a better than stock plug. Champion double platinum 7034, installed 6/13/2009. I happened to put a post on the forum due to a rain delay that day, that's how I know. Anyway, these are supposed to last longer than the originals. Guess I'll be pulling plugs out.

I agree with you on the wires and coil packs. Hence my post. I still have a MAX care warranty on this thing so if it is the coil pack(s) it is covered.

I still find it odd it started doing this right after I left the dealer. I just can not figure out the correlation. Should have been no where near anything engine related. Ughhh!!!
 
SlvrSnake said:
When I changed the plugs I went with a better than stock plug. Champion double platinum 7034, installed 6/13/2009. I happened to put a post on the forum due to a rain delay that day, that's how I know. Anyway, these are supposed to last longer than the originals. Guess I'll be pulling plugs out.

I agree with you on the wires and coil packs. Hence my post. I still have a MAX care warranty on this thing so if it is the coil pack(s) it is covered.

I still find it odd it started doing this right after I left the dealer. I just can not figure out the correlation. Should have been no where near anything engine related. Ughhh!!!
Click to expand...

Well if your under warranty make them fix it!
 
been a couple of guys with cam & crank sensors cause them grief with no codes
 
Does it fall on its face a lil when you go from low rpm to moderate? or just a back fire.

Mine would kinda fall on its face when you went from low rpm to " Push the gas a lil agressivly" it would then go back fire , die out and then go....

Pretty sure it was a bad injector issue... check your getting fuel flow on all 10 if its doing something like mine was,,
 
Crank or cam sensors going bad makes sense. Under warranty, just take it back and let them figure it out.
 
My guess is plugs! May have a cracked porcelain ! Shorting out sporadically
 
Pulled a plug looks ok but electrode is worn down, and way out of gap, over .040. It is plug from #3 cylinder.

Off to buy new plugs. I'll post up after I get them swapped. Just didn't think these would wear out that quickly. These motors are brutal on plugs.

Well see what happens with new plugs. If that doesn't fix it. Off to the dealer it goes. Plugs and wires are obviously not covered anyway so since the plug looks good I'm leaving the wires.

IMG_20130520_102557_732.jpg
 
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Stick with the stock type plugs, no need for anything else.
 
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