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Discussion Starter · #1 ·
My Jeep:
2007 with magnacharger and some exhaust work, stock otherwise.

My Problem:
Was driving down the highway and decided to go to the top of 4th gear (~140mph) and when I got close to red line, acceleration stopped (kind of like it had a governor and the fuel shut off). I slowed back down to highway speeds and noticed that when the throttle was pressed, it ran much rougher than normal. Pulled over, shut it off, restarted. It cranked longer when starting, and idled quite rough. When driving at speed and letting off the throttle, I notice "pops" coming from underneath the Jeep, does not pop when throttle is pressed. Acceleration gets rougher until I feel boost kicks in, at which point everything seems to smooth out. Wide open throttle is the only thing that feels normal, but when I let off it is back to rough and popping.

Did I damage the supercharger? Is it engine internals? (I assume not since WOT feels fine). I am out of ideas.

Please help!
 

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How many lbs of boost?

Did you look under the truck for puddles, or check your fluids for any signs of damage?

While the truck is running, go behind the truck and listen to and smell the exhaust. Is it white? Stink like gas?
 

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Discussion Starter · #5 ·
6lbs of boost
No error codes
No a/f gauge
36 degrees out
Exhaust sounds choppy, smells like exhaust
No fluids leaking
There is a metallic sound coming from under engine bay at idle which is also new, and also noticed that the interior lights are flickering when at idle now.
 

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6lbs of boost
No error codes
No a/f gauge
36 degrees out
Exhaust sounds choppy, smells like exhaust
No fluids leaking
There is a metallic sound coming from under engine bay at idle which is also new, and also noticed that the interior lights are flickering when at idle now.

If the idle is choppy, that will make the interior lights flicker. The metallic sound is not a good sign. How many miles have you had the Maggie on? Is it the Magnacharger base tune or a CMR? Did you check the belt?
 

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Discussion Starter · #9 ·
If the idle is choppy, that will make the interior lights flicker. The metallic sound is not a good sign. How many miles have you had the Maggie on? Is it the Magnacharger base tune or a CMR? Did you check the belt?
Maggie went on in April, maybe 15-20k miles since then. It was dyno tuned by the installer, I asked him to make the tune extra safe since I tend to drive it pretty hard.
 

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Maggie went on in April, maybe 15-20k miles since then. It was dyno tuned by the installer, I asked him to make the tune extra safe since I tend to drive it pretty hard.

There is a possibility you went lean in the colder temps. Was it warmer when he did the dyno tune; is this the first winter with the Maggie? Even if he made the tune "extra safe", it could still need more fuel in colder temps.
 

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There is a possibility you went lean in the colder temps. Was it warmer when he did the dyno tune; is this the first winter with the Maggie? Even if he made the tune "extra safe", it could still need more fuel in colder temps.
No doubt that he went lean for too long :(
 

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Running a supercharger on a stock engine WITHOUT an a/f guage...you asking for problems man. Even if you tuner did do a super safe tune, how would you kno your running lean if say you BAP quits or malfunctions?? you wouldnt untill you wreck something.
 

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Maggie went on in April, maybe 15-20k miles since then. It was dyno tuned by the installer, I asked him to make the tune extra safe since I tend to drive it pretty hard.
I would get a wideband on your Beast ASAP, but I think you went lean too long and hurt a Piston. Personally I want to know exactly where my AFR is at all times as when it gets colder out here as it will show that I am running leaner.
 

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Discussion Starter · #14 ·
Running a supercharger on a stock engine WITHOUT an a/f guage...you asking for problems man. Even if you tuner did do a super safe tune, how would you kno your running lean if say you BAP quits or malfunctions?? you wouldnt untill you wreck something.
It's not running a BAP, I was assured by installer and magnuson that one is not necessary at 6lbs boost.

It was much warmer when tuned, this is the first winter the Maggie has seen.

Its not looking good the longer I think about the possibilities.

Check engine light came on when I was just out. I am out of town and don't have access to my trinity, so I will get the code pulled tomorrow and update the thread.

I am afraid I might need a new engine with some free flowing heads and a blower cam.... darn...

My credit card is melting at the thought of it.... already need a new tranny...
 

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It's not running a BAP, I was assured by installer and magnuson that one is not necessary at 6lbs boost.

It was much warmer when tuned, this is the first winter the Maggie has seen.

Its not looking good the longer I think about the possibilities.

Check engine light came on when I was just out. I am out of town and don't have access to my trinity, so I will get the code pulled tomorrow and update the thread.

I am afraid I might need a new engine with some free flowing heads and a blower cam.... darn...

My credit card is melting at the thought of it.... already need a new tranny...
Exactly , 6lbs Maggie runs no BAP , So colder weather = an easy full psi or more . I still thinking you went lean for toooooooo long :) , I just looked up a 6psi Maggie log on 40 degrees temps and he made 7psi with CAM/Headers , so tells me that you are making more .
 

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It's not running a BAP, I was assured by installer and magnuson that one is not necessary at 6lbs boost.

It was much warmer when tuned, this is the first winter the Maggie has seen.

Its not looking good the longer I think about the possibilities.

Check engine light came on when I was just out. I am out of town and don't have access to my trinity, so I will get the code pulled tomorrow and update the thread.

I am afraid I might need a new engine with some free flowing heads and a blower cam, and an A/F guage.... darn...

My credit card is melting at the thought of it.... already need a new tranny...

^Fixed it for ya. Yeah, the engine light is most likely a misfire code. Well at least there are some great deals going on now, you may not have to spend as much as you think.
 

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As others have said, you really need to invest in an AFR gauge. That's all I look at as soon as the boost comes on, especially during the colder winter months.
 

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Discussion Starter · #18 ·
As others have said, you really need to invest in an AFR gauge. That's all I look at as soon as the boost comes on, especially during the colder winter months.
I read it. I heard it. I knew it. I had plans on doing it, have the pillar pod already, have links saved to buy an AFR gauge. I was planning on doing it the same time I was going to change the pulley to 8lbs and get it tuned again. If it made it that far, not sure the dyno session would have gone well...

Back to original question, what might have I broken? Is it safe to drive it 200 miles home? Should I have it towed?

Who has deals on long blocks right now?
 

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You have either broken a ringland on a piston or burned a hole in a piston. My guess is you've lost a cylinder for sure. You can start by checking your plugs. I'd start with number 4 and 6 cylinders first. They like to break first for some reason. While you're checking plugs, I'd do a compression test also. Good luck man but it don't sound good.
 

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Call Demon Performance for long block deals. As for the AFR, you said you have a Trinity, just get a LCM-1 sensor from Aeroforce and wire to a 2.5mm stereo jack then plug into the Trinity. now you are easily monitoring and logging and the most cost effective way!
 
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