hey guys,

im new to the forums, but i have something weird going on with my 2005 5.7 magnum. it started idling a little bit rough, similar to a steady mistiming, and if i accelerated too quickly it would stall shortly after. also approaching stoplights, the motor would idle rougher than normal until it downshifted to 1st gear, but it would still be slightly rough once stopped. i went home hooked up the code reader and it shot out a code p0302 (misfire on #2). i tried swapping the coil pack and plugs from cylinder 2 to the neighboring cylinder 4, and checked wiring. then i wiped the error code and it still came back p0302. i thought maybe a valve spring was to blame so i pulled off the valve covers and checked it out and they appear to be ok, tested by pulling the fuel pump fuse and cranking the motor and watching em move up and down. i have a compression tester and it said cylinder 2 gave a 70 psi...which i know is low. i have not tested the other cylinders yet, but i probably should. i guess im wondering what the next step is before i pull the motor (if i have to i will). And the kicker is i had the motor rebuilt from a non local machine shop guy about 3 months ago and it was running fine after. they did put in a refurb passenger cyl head cuz my other one was toast. i am not as mechanically inclined as many of you i am sure, but im willing to learn and try stuff. i have tons of pics and videos of what i have had done if ya want em. i need the dodge pros lol im stuck. thanks for reading

-Dan

 

So I also wanna add that there was a white residue near my airbox vent, and when I take off the breather tube that goes into my air box, a bit of white-ish smoke comes out whenever the car is running. Also i used a stethoscope to listen to both the driver and passenger valve covers. the passenger side valve cover was making clicking sounds while motor was running.

 

well no responses...i thought these forums would be more active. anyways i finally have some time and i plan on wrenching on the car over this weekend. ill post what i find later.

 

Update...compression tested cylinder 2 again...got the same 70psi at start and 60 consistent after initial crank. Added a teaspoon of oil and tried again...it shot up to 120. Testing another cylinder for a wider test group. Got 120 psi cold on cylinder 4

 

well i pulled the motor apart entirely...and i know the community is on pins and needles to hear what i found lol. looks like a valve seal failed in cylinder 2 and a piece of it got knocked around by the piston. this caused the piston/piston rings on cylinder 2 to get a little beat up. im thankful that the cylinder wall was not damaged. im going to get one new piston/rings...if getting one piston/ring is even a thing. i am just guessing you are supposed to redo them all? ill just ask an actual mechanic. and obviously repair the cylinder head, valves, and fresh gaskets/seals all around and ill put it together sometime this week when i get time.

 

here are some pics to help

 

The Magnum and Charger sections here aren't as active as some of the dedicated forums around the net. I just now saw this today...and I'm a moderator.


Anyway, I work on 20 or more LX cars every week, so fire away if you have any questions.


Did some leave a bolt on the cylinder? Holy crap

 

do you recommend that i replace just the problem pistons/rings (looks like 2 pistons need replacing), or that i do all of them? Also i put some better pics of the heads and i noticed something...passenger side valves for cylinder 2,4 look much darker than cylinder 6,8...driver side only cylinder 1 is dark, the rest look much lighter. and lastly, any idea what happened? car drove perfectly fine for like literally 5 months after i had it rebuilt (by some guy, i was trying to save $$...HUGE mistake)

 

What hit the pistons? Do you know?

 

I am guessing some part of the valve or valve seal...it's hard to tell...The oil looked perfect, no chunks or anything. I decided to get new everything (Pistons, rings, gaskets, oil pump, timing chain, machined heads w/ new valves/seals, etc) no Mickey-Mouse fixes. I'm going to order my stuff on Thursday and I'll post more once I put it all together and reinstall. Also, have u heard of people putting these motors together and the a/c is stuck at the pressure switches? that's what happened last time and I had to take it to a place cuz I didn't know how to get it to pass those switches