General Tech Good at troubleshooting? Have a non specific issue? Discuss general tech topics here.

Misfire 3.8 Chrysler Town & Country, 185K mile, 2003

  #1  
Old 02-10-2016, 01:06 PM
Junior Member
Thread Starter
Join Date: Oct 2011
Posts: 5
Default Misfire 3.8 Chrysler Town & Country, 185K mile, 2003

Symptom:
Codes PO303, PO306, PO300; very rough idle and misses at all rpms.
Sooty wet exhaust. Mostly highway miles, but some in-town miles also.
I have notice headlight lights slightly dim at deceleration at 20-30 mph.

Diagnosis completed so far:[*]Compression tested all cylinders (cold engine and dry cyl). Pretty consistent ~145psi all cyl.[*]Performed leak down test. Homemade tester @60 psi .034” orifice and got 10% leakage.[*]Pressured each cylinder to 70 psi @ TDC and no bubbles in radiator.[*]Fuel pressure at fuel rail 45 psi. I have not checked the flow, but van will easily run 85mph.[*]Performed smoke test & sprayed starting fluid. No obvious vacuum leaks.[*]Looked at valve springs on cylinders 2,4,6 no broken springs. Haven’t check cylinders 1,3,5.[*]Clean & bench tested injectors. Moved #3 & #6 injectors to difference cylinders, but miss stayed at 3 & 6.[*]Ohm tested Coil – prim & second at spec and all cylinders have spark. I did not load test the coil.[*]All plugs (platinum NGK) look tan and no excessive wetness or carbon. New Mopar wires 3 yrs ago.[*]Checked sensors IAT, IAC, TPS, MAP, PCV. All appear in spec per shop manual (no EGR valve on engine).[*]Checked continuity on power and signal wires to coil – all are good[*]Checked for chafed/burnt wires by exhaust cross-over pipe. All were good as was the connector.[*]Checked connectors to PCM. All connection look like new.

Had local shop hook to more sophisticated test equipment and he found nothing. I am not sure what he did, but he said the PCM is good. He said he thinks the issue is carbon around the valve seats and he could fix for $1000. I checked with some dealers and they agree it could be carbon on valve seats, but I am not convinced this would make such a rough idle and miss at all rpms. Anyone with good diagnostic knowledge, please chime in. This one has got me stumped! Thanks.
 
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Chrysler Forum Editor
Brand News, Concepts & Rumors
0
09-20-2012 06:08 PM
xdm
General Tech
2
01-21-2011 05:41 PM
merry
Off Topic
4
01-04-2009 10:47 PM
cherry
Off Topic
0
08-25-2008 09:03 PM


Thread Tools
Search this Thread
Quick Reply: Misfire 3.8 Chrysler Town & Country, 185K mile, 2003


Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.