Cylinder 4 misfire

Michael Owner/Technician Pennsylvania Posted   Latest  
Unsolved
Driveability
2011 Ram 1500 Outdoorsman 4.7L (P) 5-spd (545RFE)
P0304 — Cylinder 4 Misfire Detected

Dead misfire on #4. Did a clear flood and to me that sounded ok. No abnormal cadence. Both the intake and exhaust plugs were severely carbon fouled and the customer had us change the oil while it was here and we captured maybe a quart of oil. I put 2 new plugs in it and no change whatsoever. Misfire counts just kept climbing up. I did an in-cylinder cranking and running of #4 and #2 (known good) I am not proficient at all with analyzing the in-cylinder so I am making assumptions based on what I see. The #2 running has an area that looks different than #4 during the intake stroke. Can someone help me analyze this?

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Raymond Mobile Technician
New York
Raymond Default
 

Try doing a regular compression test, with that little oil you could a bad ring

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Michael Owner/Technician
Pennsylvania
Michael Default
 

174.3 on that #4 cylinder

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James Owner/Technician
Saskatchewan
James Default
 

Did it spit a rocker arm?

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Michael Owner/Technician
Pennsylvania
Michael Default
 

Wouldn't it have a noisy valve train? It is quiet

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Brian Instructor
Ohio
Brian Default
   

This example of 4.7 with a thrown exhaust rocker was quite when running. This this a 2 valve engine? If so you would definitely see no evo., and no ivo would pull a negative pressure . Here is a 4.7 with exhaust rocker arm spit . diag​.​net/file/f5qqi7z3f…

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Robert Diagnostician
Florida
Robert Default
 

Thanks for sharing that failure i too am pretty new at using this type of method for diagnosis seen plenty of known good ones to see actual failures and what the failures are gives allot of learning experience for those of us new to this game. Thanks again.

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James Instructor
Quebec
James Default
 

Looking at the two seems like an exhaust valve is lacking definition even in the exhaust pocket. put an image of 2 superimposed on 4 slightly offset higher so you can see the difference. That being said, the only 1 litre left in the oil pan and the carbon fouled valves would lead me to looking at crankcase pressures .

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Brian Instructor
Ohio
Brian Default
 

I am working to get better at analyzing pressure patterns, I agree that evo is not very obvious. Here I tried to use reference wave form. Also some difference when the intake valve opens? I am learning so let me know.diag​.​net/file/f3ld9ezmt…

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Marek Technician
Wisconsin
Marek Default
 

I would do a regular compression test on all cylinders for comparison purposes. 1 quart of oil is inadequate for any engine, especially that one. if all cylinders are with-in spec, I would lean toward a fuel injector issue. Also, I would be really surprised if that engine will ever function properly knowing that it only had 1 quart of oil upon arrival. I'm assuming you already swapped coil and…

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Ray Diagnostician
Ontario
Ray Default
   

I would start over with disabling the fuel, put 1 channel on COP 1, the WPS or a FLS on the dipstick tube using an old COP boot, in the intake, in the tailpipe, at WOT cranking, with sponges stuffed in the tailpipes. If the engine mechanical tests ok, scope the cyl 4 spark plug burn times and scope the injector volts and amps.

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Brian Instructor
Ohio
Brian Default
 

Ray does the sponge in the tail pipe increase the response of the pules sensor? I will have to try that.

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Ray Diagnostician
Ontario
Ray Default
 

Yes, stuff sponges into the tailpipes to pick up up good signals while cranking. I,ve found broken valve springs with that method.

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Caleb Diagnostician
Indiana
Caleb Default
 

Hello Ray. Is your cell number still the same as you mentioned in a post about 10 months ago where you were going to do a meetup up with some other Canadians??

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Ray Diagnostician
Ontario
Ray Default
 

Hi Caleb, my cell number is still the same but i don't recall any meetup.

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Caleb Diagnostician
Indiana
Caleb Default
 

Ok when I call it ,it just goes too voicemail or maybe you are busy lol. I would post it here again to make sure I have the correct one but not sure if you want me to do that.

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Ray Diagnostician
Ontario
Ray Default
 

Hi Caleb - sorry for this confusion. Please send me your cell phone number to my email so I can call you as well as re-enter your number (which has been blocked - hence it going to voicemail). … - that way we can connect 'in person'. Look forward to hearing from you.

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Caleb Diagnostician
Indiana
Caleb Default
 

Email sent. Thank you!

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Geoff Diagnostician
Hawaii
Geoff Default
 

Ray what does " in the intake, in the tailpipe, " mean? Can you re-write that maybe? I can't figure if you are using four sensors or doing mulit/different test. Thanks

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Ray Diagnostician
Ontario
Ray Default
   

To find any compression, valve, rocker, cam lobe, lifter issues quickly, first, disable the fuel system On one channel, connect to cyl 1 ignition. On another channel, connect the amp probe to measure the starter amp draw. The engine can have good compression, but still have valve/lifter, cam lobe issues. On another channel, connect the WPS500 or the FLS to the intake manifold and crank at…

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Geoff Diagnostician
Hawaii
Geoff Default
 

Thanks Ray. Next time you do it, can you take a picture of "connect the WPS500 or the FLS into one of the tailpipes and stuff some sponges into the tailpipes" ? No rush, just some day. Thanks man!

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Ray Diagnostician
Ontario
Ray Default
 

Hi Geoff, I'll take some photos, but if you look at the Pico TA087 Exhaust Adapter for the WPS500, just put the adapter into a tailpipe and stuff some sponges into the tailpipes.

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Geoff Diagnostician
Hawaii
Geoff Default
 

are the sponges instead of using the inflatable balloon thing? (can't recall the name) You're saying put the sponges AROUND the probe. I thought you had that inflatable thing, that's how/why I got so lost.

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Ray Diagnostician
Ontario
Ray Default
 

Hi Geoff, the sponges are stuffed around the probe only to force most of the cranking exhaust pulses into the probe.

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Caleb Diagnostician
Indiana
Caleb Default
 

Not trying to be a jerk but I dont see anywhere in your post were its says you verified spark?

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Gary Owner/Technician
Michigan
Gary Default
 

Try a regular compression test and a cylinder leakage test. Maybe old school, but have found many a in cylinder problem that way.

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Eric Owner/Technician
Wisconsin
Eric Default
 

Did you check fuel trims? Verify injector operation? Did you verify ignition? How many miles on the vehicle? How many miles since the last oil change? Since you have a scope why not perform a relative compression test? I'm really not a fan of "sounded" or "looked" okay. Too much room for error. Make measurements and provide actual results, not "in normal range" or similar. I feel you have…

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Michael Owner/Technician
Pennsylvania
Michael Default
 

Eric, sorry for the lack of info here. I rushed into making this post. I do have more info i'll share with later

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Douglas Technician
Maine
Douglas Default
 

The 4.7 engines are known to have the rocker arms fall out and the valve train is quiet when a rocker has fallen out, but will have a constant misfire in that cylinder. I’ve seen this multiple times, fairly quick to pop a valve cover to look.

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Douglas Technician
Maine
Douglas Default
 

Rocker or “Cam follower” since it’s an overhead cam, my terminology is old school

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Geoff Diagnostician
Hawaii
Geoff Default
 

Doug, first time someone said "follower" I spent an hour looking for pictures to figure WTF they were talking about. :-)

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Ken Owner/Technician
Arizona
Ken Default
 

Try a vacuum gauge on the intake also....

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Stuart Mobile Technician
Illinois
Stuart Default
 

Sounds like a thrown rocker​.​These motors are known for this​.​Being that low of oil,I'm suprised that is all that is wrong with the truck.

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Caleb Diagnostician
Indiana
Caleb Default
 

What did you find Michael??

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Michael Owner/Technician
Pennsylvania
Michael Default
 

There were some details I didn't include but spark was good to answer your question. In-cylinder cranking I was seeing 5.3 psi delta between the intake and exhaust pocket. Ccustomer declined further diag and took the vehicle.

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