Page 1 of 1

Cel flashing under wot above 5000rpms

Posted: Tue Apr 16, 2013 10:08 pm
by SJT2
I have an 02 R/T

The problem is under wot above 5000 rpms my check engine light flashes. Sometimes it goes out and other times it stays on throwing a code p0300 misfire code.

I've changed the plugs and wires and also cleaned my air filter (AEM cai). I have good fuel pressure and I can her my secondary intake runners opening. What am I missing?

Posted: Tue Apr 16, 2013 10:19 pm
by trojmn
What did the fuel pressure gauge say at 6000RPM WOT?

P0300 is a code for random misfire, and your at WOT so likely that's lean misfire. check for air leakage intake and exhaust and of course fuel pressure at WOT/high RPM.

Tro

Posted: Wed Apr 17, 2013 7:46 am
by r/tguy02
you using an UDP?

Posted: Wed Apr 17, 2013 8:59 am
by Danteneon
:withstupid:

That is a common issue with 2002 Magnum engines.

Posted: Wed Apr 17, 2013 9:14 am
by SJT2
I'm going to check again for intake/exhaust leaks but I didn't find any last week.

I don't have an UDP. I was looking into them until I read that they cause problems on some years. If this is a common problem what is the solution?

Posted: Wed Apr 17, 2013 9:59 am
by occasional demons
There is no solution for the UDP related problem. The '02 pcm is much stricter on crank oscillation tolerance. You could downgrade to an '01 R/T pcm...

But you may want to check the damper for any signs of damage. Also anything connected to it. Belts, driven accessories, anything that may be affecting the harmonics.

The only other things may be the coil, crank sensor, or cam sensor getting weak. But that is kind of tough to determine. And expensive to replace parts to chase a problem.

Posted: Wed Apr 17, 2013 10:15 am
by SJT2
Looking again I noticed my passenger side motor mount is ripped. Would that cause this problem if the engine was vibrating/moving around at high rpm?

Posted: Wed Apr 17, 2013 12:18 pm
by occasional demons
Not unless the damper is rubbing on the frame from it. :lol:

Posted: Wed Apr 17, 2013 12:21 pm
by Danteneon
That...would be bad times :shock:

Posted: Wed Apr 17, 2013 12:25 pm
by SJT2
Ok. I do have to change the upper and lower right mounts. They're both shot. If the rain holds off I'll check a few more things. Thanks for the ideas everyone.

Posted: Wed Apr 17, 2013 5:04 pm
by OB
Did you replace the coil pack? Also could be a sticking or burnt valve in the head. If it isn't misfiring, possibly an issue with cam or crank sensor at high rpm. Does it happen if you slowly rev above 5k, low throttle input?

Posted: Wed Apr 17, 2013 5:19 pm
by SJT2
I didn't change the coilpack. I have no misfire at all unless above 5k at WOT. I may try Seafoam and see if that helps. The car runs great other than this problem.

Posted: Wed Apr 17, 2013 11:35 pm
by occasional demons
Valve float could be another potential cause, if there is a weak spring or two.

Posted: Thu Apr 18, 2013 12:48 am
by SJT2
occasional demons wrote:Valve float could be another potential cause, if there is a weak spring or two.
I really hope that's not the problem. Out of curiosity how much is a set of springs for a Magnum motor?