Consistent misfire on Cylinder # 4 (P0304)
Login  | |
|
Consistent misfire on Cylinder # 4 (P0304) - 6/28/2008 8:17:46 PM
|
|
|
husker6:33
Posts: 7
Joined: 6/28/2008
Status: offline
|
Hello – I hope I’m not going out of my lane on starting a new thread. I have read many threads that pertain to misfires but wanted to get a fresh one started to get specific feedback to my problem. I purchased a 2004 Disco II 6x months ago with a blown head gasket (Can’t do anything about it now). It looked and ran great when I was looking at it but I guess looks can be deceiving. I bought it in New York and drove it home to Virginia Beach, 200 miles into the trip the service engine soon light came on. I stopped at a AutoZone in Jersey and got a P0304 code, misfire on Cyl # 4. I had the code cleared and continued on. I stopped again for a bite to eat and it popped again. It didn’t ride rough so I figured it would be fine for the rest of the trip. The only odd thing I notice was the sound of flushing water inside the dash (assuming it’s the heater coil). I completed the trip with no issues. All fluids were good and it ran fine. I did a little bit of research using this forum and did the following listed below.
- 1st - replaced cyl # 4 plug, problem continued
- 2nd - replaced high tension lead for Cyl # 4, problem continued
- 3rd – I learned about the sister cylinder and replaced cyl # 7 plug, problem continued
- 4th - replaced high tension lead for Cyl # 7, problem continued
- 5th - replace coil pack controlling ignition for 4 & 7, problem continue
- 6th – Did a Block test - Did some more researched and found that a small coolant leak from a cracked block or blown head gasket can cause this problem (If not true, let me know). I did a block test, blue to yellow. Compression for the cylinders matched so I jumped to the head gasket as the issue. Cyl # 4 plug was oddly discolored and seven matched the others so I leaned more towards cyl 4 than 7. After I tour the right bank apart I found the results inconclusive. Everything looked good, no holes or breaks in the gasket (I looked using a magnifying glass). There was no coolant jackets near 4 so I then assumed the problem was in 7. I found coolant in 7 but since the piston was covered in carbon, I assumed it came from the jacket when I pulled the head off. I dropped the heads off at the local machine shop and got the heads decked and pressure checked, everything came back good to go. I put everything back together within specs and swapped the injectors around, just incase they were the problem. 40miles after the head job, I’m getting the P0304 code again. I''m thinking a cracked block but I''m looking for suggestions?
Thumbnail Image
Thumbnail Image
Thumbnail Image
Thumbnail Image
 Attachment (4)
|
|
|
|
|
|
|
RE: Consistent misfire on Cylinder # 4 (P0304) - 6/29/2008 4:50:44 AM
|
|
|
LrTECH
Posts: 34
Joined: 8/30/2005
Status: offline
|
Could possibly have a sticking valve. Its a common problem
|
|
|
|
|
RE: Consistent misfire on Cylinder # 4 (P0304) - 6/29/2008 6:10:29 PM
|
|
|
husker6:33
Posts: 7
Joined: 6/28/2008
Status: offline
|
LRTECH, thanks for the input. What can I do to confirm/ deny a sticking valve?
|
|
|
|
|
RE: Consistent misfire on Cylinder # 4 (P0304) - 6/29/2008 7:18:32 PM
|
|
|
CandiMan
Posts: 153
Joined: 2/6/2008
From: Charlotte, NC
Status: offline
|
Besides decking and pressure testing the heads, what else did the machine shop do to them? Did they check the valve guides and reface the valves? If they did a complete head reconditioning, it''s unlikely you have a sticking valve.
Mixing around the injectors was a good idea. Did you do the same for the plugs, did you mix them around? If so, can you verify the current condition on plug #4. If plug #4 is still cleaner than the others, it''s looking more like a crack block.
_____________________________
Mike L.
98 Disco 4.0
|
|
|
|
|
RE: Consistent misfire on Cylinder # 4 (P0304) - 6/30/2008 5:25:37 PM
|
|
|
husker6:33
Posts: 7
Joined: 6/28/2008
Status: offline
|
Mike L - thats all the machne shop did (decked and pressure checked the heads), Sad to say but I didnt have the money for a valve job. Everything looked good.
During initial trouble shooting a couple months back I did swap around the plugs. The word to desribe # 4 is not cleaner it was more a different color. All others were white where # 4 had a little more brown.
I have her parked in the garage right now. I''m gonna get a bore scope and check out # 4 this weekend. I figured if she is leaking I will be able to see something.
Whats your take on using the fix it stuff in a bottle?
|
|
|
|
|
RE: Consistent misfire on Cylinder # 4 (P0304) - 6/30/2008 7:30:49 PM
|
|
|
CandiMan
Posts: 153
Joined: 2/6/2008
From: Charlotte, NC
Status: offline
|
quote:
ORIGINAL: husker6:33
Mike L - thats all the machne shop did (decked and pressure checked the heads), Sad to say but I didnt have the money for a valve job. Everything looked good.
During initial trouble shooting a couple months back I did swap around the plugs. The word to desribe # 4 is not cleaner it was more a different color. All others were white where # 4 had a little more brown.
I have her parked in the garage right now. I''''m gonna get a bore scope and check out # 4 this weekend. I figured if she is leaking I will be able to see something.
Whats your take on using the fix it stuff in a bottle?
I am not exactly sure which "fix it stuff in a bottle" you are refering to because there are quite a few out there on the market. Personally I have not tried any fix it stuff in a bottle, but I will be shortly. My Chevy S10/S15 puffs blue smoke when cranking with a cold engine. Which is an indication of worn valve seals. One of these days I''ll try a fix it stuff in a bottle to see if it stops (or reduces) my valve seal leak.
When you do try the bore scope, don''t forget to rotate the crank shaft so you can scope the cylinder at different piston height. Ideally if you can pressurize the cooling system while scoping that would also help.
I''m also in the process of rebuilding a 98 Disco. From brakes, engine, interior and exterior. I''ve completed the brakes, now I''m working on the engine which is turning out to be more of a challenge that I originally thought.
_____________________________
Mike L.
98 Disco 4.0
|
|
|
|
|
RE: Consistent misfire on Cylinder # 4 (P0304) - 6/30/2008 8:49:38 PM
|
|
|
husker6:33
Posts: 7
Joined: 6/28/2008
Status: offline
|
Mike L - I have been looking at all options on the shelf at NAPA, Autozone and Pepboys. The one that catches my eye is the
K AND W Product that uses NANOTECHNOLOGY. It runs about $20.00. I have been thinking real hard on whether or not its worth the try. I dont have much of a option though. I would love to drop a RPI 5.2 with an LPG system but its not practical with gas prices, plus the seasonal prices of LPG are not worth it. My only concern about using the fix-it-stuff in a bottle is the damage that may occur to the rest of the cooling system. Since its considered permanent and bonds everything together, I would hate to tear the heads of then.
I appreciate the pointers on pressurizing the cooling system. I figure I''ll see a small amount of coolant after she sits for a while. I usually get the misfire during cold starts. I will take pictures and post them.
I bet your enjoying the 98 rebuild. Where are you at on the engine rebuild?
|
|
|
|
|
Printable Version
