Code P0305 (#5 misfire) and Oil in the Cylinder (1 Viewer)

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Joined
Feb 14, 2011
Threads
6
Messages
46
Location
Peoria AZ
Hi all -

I've been lurking on this site for awhile and I was hoping my first post would not be to ask about an issue with my LX450... but such is not the case. I have a 97 LX450 with 127k miles that I bought in December 2010. It has been running perfectly, and I have been slowly working on baselining it (new fluids, plugs, wires, cap, and rotor, etc.).

A couple days ago when I was about a block from home it started misfiring real bad and had a very rich fuel smell (no CEL). It happened at night so I took a quick look under the hood for anything obvious - nothing.

The next morning it started up and ran smooth with no issues. Drove it around the block and to the store - no problem.

The next time it was okay going to the store, but when I started it to come home, the problem came back. I limped it about a mile home and the CEL came on.

Bought a scan tool and read out P0305 (#5 misfire). Also, I started it again when the engine was cold and after turning it off, I noticed that there was wetness (slick, oily fuel) where the rear exhaust manifold bolts to the exhaust pipe.

Sorry for the long-winded post, but does anyone have any ideas on what I might be in for? It seems like head gasket symptoms include coolant, so I'm not sure. Rings maybe? But why all of the sudden, and why did it go away for a day?

Thanks in advance for the help...
 
Have you checked the number five plug and injector? Also have you checked the code in the FSM for trouble shooting methods?


Search is your friend as the old saying goes here on Mud...
 
Thanks for the link. I've found all kinds of great info on this site - but could not find much on this issue (probably because I searched for everything except "P0305 Help"). Anyway, the oily fuel at the exhaust flange is throwing me off.

I haven't checked the plug or injector yet (work keeps interfering). I did inspect the harness by the EGR and the wrap looks/feels good. However, I WILL unwrap it after reading the other posts.

I guess I know what I'm doing this weekend.
 
same thing happened to me two months ago. source of the problem was fuel injector on cyl#5 stuck open and some of the wire close to egr was burnt. got replacement injector form MAF for $185, replace the burnt wire. now it runs smoother than it ever been.
 
I found the issue! The short was at the ECU connector. It's a tight fit in there and the wire bundle was rubbing against the horizontal bracket that holds the glove box (see where screwdriver is pointing in photo).

Some other threads and members steered me in the right direction (thanks 94srunner and bromo) - otherwise I would have been completely lost. Here's how I found it in case anyone else has similar issues:
  • Removed heat tape around bundle at EGR (after removing EGR to get some room), but didn't see any bad wires.
  • Removed #5 injector connector and connected a volt meter. It read a solid 12V with key on, engine off.
  • Started wiggling the harness all the way up to the firewall.
  • Voltage started bouncing around at the firewall (had to wiggle it hard though).
  • Removed the glove box and found the short near the connector.

2011-03-19%2015.57.11.jpg


So what's the best way to wrap the bundle by the EGR? One of the threads said to order something from Jegs or Summit. Does any chain parts store carry anything sufficient? I want to get it on the road again ASAP.
:cheers:
 
Napa has a cloth mesh spark plug boot heat shield that is tube like with a metal ring on one end. You can snap the ring and cut the mesh, then use hose clamps and/or wire ties to secure it around the wiring harness adjacent to the EGR.

I just searched Napa's website for it but could not find it. I found mine at the local Napa on one of the small turnstyle racks by the checkout counter.
 

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