4.6 intake valves help!
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4.6 intake valves help!
I have a 2001 f150 with the 4.6. It has 85k. Three days ago it started missing bad. I checked the codes and had misfires on #2 & #6 & #7. The # 2 plug was melted. I changed plugs and coils. The missing did not go away, but only showed misfire on #2. I replaced the injector, nothing. Checked eveything i could think of. I did a leak down test on all cyl. #2 showed 100% leak, #6 was about 75%. The intake valves are shot. I know running lean will cause this, but i can't find anything wrong. I was suspecting water in the gas. Any ideas would be great.
Thanks
Thanks
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Joined: Feb 2004
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From: Under My Truck
With the truck running, remove the PCV on the pass side valve cover....you shuld get a "light" amount of smoke....if at all
If it is chuggin smoke out, you have blow-by.....and that is a bottom end issue.
The exact thing took out my 4.6.....ended up that I was running was fat and the cylinder walls were being "washed" with gas....
It all stemmed from runnin 87 octane....and the 02 going bad right away....and telling the pcm/ecu that I was lean....so the pulse to my right bank went wide and too much fuel......end of days.....
Check blow-by....and if you are solid there, buy new heads (about $400) and do it yourself. Don't get stupid like me a buy PI's because then you have new issues with the intake. Also, make sure you buy new head bolts and tighten in the three steps....as directed.....
If it is chuggin smoke out, you have blow-by.....and that is a bottom end issue.
The exact thing took out my 4.6.....ended up that I was running was fat and the cylinder walls were being "washed" with gas....
It all stemmed from runnin 87 octane....and the 02 going bad right away....and telling the pcm/ecu that I was lean....so the pulse to my right bank went wide and too much fuel......end of days.....
Check blow-by....and if you are solid there, buy new heads (about $400) and do it yourself. Don't get stupid like me a buy PI's because then you have new issues with the intake. Also, make sure you buy new head bolts and tighten in the three steps....as directed.....
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No blow by. The intake valves are shot. Leak down test confirmed this. The truck was running great then it went to hell on my way to work. Just got gas. Too much gas would burn exhaust valves correct.
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Joined: Feb 2004
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From: Under My Truck
Too much gas can actually "wash" your cyl walls.....and ultimately (and rather quickly) cause your oil ring to stick/break.....and then no lubrication....
This is what happened to me. And....it was right after (40 miles or so) after a fill up....
You say no to blow by, so this points to your valves....as you suspected...
Seems like the ONLY likely suspect...
This is what happened to me. And....it was right after (40 miles or so) after a fill up....
You say no to blow by, so this points to your valves....as you suspected...
Seems like the ONLY likely suspect...
