Misfire on #.8
5th Gear Member
Joined: Mar 2007
Posts: 3,062
From: Florida
2nd Gear Member
Joined: Jul 2011
Posts: 289
From: Colorado
So has there been any idea what the real reason is behind the fail? Weak rings? Poor oil supply? I just bought a coyote with 3800 miles on it with one spun rod bearing, Im guessing it may be the rings and as a result burnt a lot of oil , caused pressure drop and spun the bearing.The Ford Tech said the motor ran great, no noise at idle just a slight rattle at high rpm , no misfire etc, plugs are burnt nice and clean too. Im pulling the pistons so Ill see how they look when I get there, planning on at least a new set of rings when I put it back together. Id like to adress the problem while Im in there and not have this pop up again once its all back together.
The old air cooled VW Beetles had a problem with losing #3(I think) cylinder. VW had to retard the timing for #3 to take care of the issue. I don't think VW ever formally acknowledged the problem either.
6th Gear Member
Joined: Sep 2006
Posts: 11,278
From: Gainesville, FL
How many of the group has had a 4.6 spin a bearing or lose a piston in the first 5K miles? I find this amazing.
The old air cooled VW Beetles had a problem with losing #3(I think) cylinder. VW had to retard the timing for #3 to take care of the issue. I don't think VW ever formally acknowledged the problem either.
The old air cooled VW Beetles had a problem with losing #3(I think) cylinder. VW had to retard the timing for #3 to take care of the issue. I don't think VW ever formally acknowledged the problem either.
Last edited by moosestang; Aug 8, 2012 at 06:13 PM.
5th Gear Member
Joined: Aug 2006
Posts: 2,460
From: Cumming, GA
1st Gear Member
Joined: Feb 2010
Posts: 115
From: Baltimore
Did you get a PO308? That is the specific code associated with the dreaded broken ringland on piston #8.
"Normal" compression readings on this engine can range from 170psi to 200psi depending on your altitude. All readings should be within 10% of each other.
It is normal to have oil on the threads of every spark plug on this engine. Not the part that throws the spark inside the combustion chamber.
Blue smoke should be coming out ot the tailpipes especially the drivers side if you broke the ringland.
Last edited by Rob72; Aug 9, 2012 at 11:19 AM.
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