Misfires on cylinders 5 6 7 and 8

fbird18

fbird18

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As some of you know, a couple weeks ago I had misfires on the passenger side and lean codes and a loud knocking. Replacing the secondary tensioner fixed all that. Now it is misfiring on all the driver side cylinders and have a lean code on the passenger side. It doesn't sound like the other side did when the tensioner broke.

Does anyone know what would cause all the cylinders on one side to misfire? I realize it probably is the other tensioner, I just don't want to believe it. I checked the coils, no oil in there. Any thoughts?

01 v8 149,000 miles
 
Are those the original coils? Be aware that coils on the LS do fail (often) without oil or water exposure. Of course, I wouldn't expect so many to fail at the same moment. I would also check manifold vacuum while at idle.
 
I replaced all the coils a year ago with motorcraft ones.

I'll be honest I never really understood the vacuum system on cars. My buddy has the gauge, so hopefully we can check it here real soon. When we do, what would it mean if I am getting 18hg? What would cause the codes then. Or if I'm not getting 18hg, would that mean I have a vacuum leak somewhere? Why would not enough vacuum cause only one side to misfire and not all of them? I told you I know nothing about vacuum systems :) :(

Thanks for the help so far :)
 
if you do not have enough vacuum - then you have a vacuum leak, meaning air is getting into the intake manifold from another place (other than the air intake tube).

This can be - leaking intake port gasket, intake manifold not on square, any number of vacuum lines cracked or not on properly, egr leak, IAC leak, ....etc.

The first thing to do it to rule it out.
 
I will add that if your vacuum reading isn't steady at idle it usually indicates a valve or valve timing issue.
 
I checked the vacuum. Got a slightly unsteady 15hg. Is that not good? I'm going to upload a video in a min.
 
Well here is a bad video. The sound sucks and you can barely read the guage, but hey what do you expect from a phone when it's all you got on ya? :) If you can't read it, it is reading 14 and slightly jumpy at that. Hey joegr, is that bad? And Quik, I know that isn't the 18 you said was good so I'm assuming I have a small leak somewhere. But do you suppose that could cause the entire bank to misfire?

Any help is appreciated, I'm pretty clueless at this point.

YouTube- vacuum pressure at manifold
 
Thanks. Yeah I know it isn't easy to help when you don't really know what's going on, and you arent there.

Now three weeks ago I had misfires on cylinders 1 and 4, replaced my passenger side secondary tensioner and it ran perfectly for the two weeks. And all the sudden I get the misfires on all the cylinders on the driver side 5,6,7,8. I did nothing to the driver side then. I need to rule out that what I did on the passenger side had no effect on the other bank, and what is happening now is not related to the work I just did. Know what I mean? I'm sure my new problem is just that, new and not related to the passenger side work.

Guess I just have to spend the long weekend researching and pulling stuff off. Any more insight or tips is greatly appreciated, especially over the christmas weekend. Thanks! :) :) :)
 
yup... check the obvious first, but is does sound like your out a tooth or two on the cam - and misfiring on the driver's side because it's sucking in exhaust gas from the passenger side....
 
Good points Joe and Quik. I think I am going to take off the pass. side valve cover and check the timing. That's pretty easy, only an hour of work or so. Man if that's the problem and it can be fixed that easy, I'll have to buy you guys a beer. It never crossed my mind that screwing up the pass. side exhaust cam timing would affect the driver side timing.

Thanks and Merry Christmas everyone!
 
How did you change your tensioners? did you take the front timing cover off? or just VC. if just vavle cover how did you remove it w/o taking chains off? thanks.
 
Update: FIXED! AGAIN!

Turns out it was my other secondary tensioner (driver side) causing the misfires. This one actually did jump a tooth on the exhaust cam and that is why all the cylinders were misfiring. When I did the passenger side a month ago the timing was still correct with the chain and the exhaust cam, just the tensioner broke.

I got lucky though this time. The busted off piece of tensioner was wedged between the chain and cam gear and should've caused the chain to break like I've read others doing. But it was just wedged in there getting wore away by the chain. It did cause the gear to slip a tooth, but all is fine now I believe.

I highly recommend anyone with 140,000 mi or more to pull the covers off and check these. It seems quite a few have gone out right around there, and getting to them before they break and possibly causing even more engine damage, is well worth the 5 or 6 hours to replace them. That's about how long it took me in my cramped garage with mostly basic hand tools and 10 degree weather. If I can, most of you can. I'm right at 149,000 and both of mine failed i.e. broke, within a month of each other. And if you do catch it before it snaps a chain, you can replace both tensioners by taking off the valve covers and removing the exhaust cams (bottom cam). It's a relatively easy job, just takes a little patience and elbow grease and really loving this damned car :D.

jt351
I just took off the valve covers. Then remove the 5 bearing caps holding down the camshaft, keeping thier orientation and placement in order (they must go back to where they were taken off). If you mess up the order it's ok. They are numbered in order and have little arrows that point to the front of the car. Then remove the bolts holding down the tensioner. Lift the camshaft up and out of its resting place, careful not to scratch any of the contact surfaces. From there you can maneuver it around and pull the tensioner out. I am of course skipping the specifics like checking the timing and torque values. But those have been talked about in recent threads.
 
Yep. No codes. No knocking or weird sounds. No extra bolts when I was done. I think I'm good :D
 
Damn Nic, your car just has issues after issues :( I feel sorry for you :( But you get them all fixed so yay!
 
Yeah it sure does. Probably cuz I beat on it so badly :rolleyes:. I think it's just one of those cars that are doomed from the begining. When I bought it the dealer got the carfax, and from brand new to 40,000 miles it was a rental :eek:. I can only imagine how bad it was treated then. But you're right, I just keep on fixin her :Beer Oh wait you aren't old enough for that stuff yet :D
 
Ive done my share of fixin on my b*tch :P out of storage drivers side VCG Coils and Plugs are being changed. Fixing my leaky oil issue this weekend, and then hopefully trading in for a 95 - 96 Impala :D

Ive also fixed my radio about 35 times since I got it too...
 
Thats cool to know about changing tensioners, that is not in the books, I just got done fixing my ls, I bought it with a bad secondary chain that had broke from the tensionor jumping into the link and braking it, well it bent 2 valves in the process, I am a mechanic and a consider myself a ford specialist but what a MF. I told myself I was going to replace both secondary tensionors And am glad I did, the non broken side had a huge crack in it. I saw a magazine a while ago that had a fix for 4.0 jags, it told you to cut the sec chain and replace tensionor and had a new chain with a replaceable master link, I was not that lucky and pulled the head, All I can say is Both of My F&*^ing pumps now only have 3 bolts holding them in place, that is just stupid to put 6 inch long bolts behind a line you cannot get off, Of and the car only had 110,000 miles and was as clean as a whistle inside, And I just did VC gaskets on a customers 01' ls with just under 200,000 miles all original they bought it new and the tensionors showed no signs of cracking, go figure.
 
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