I am having missfires on 5,6,8 and was told to check my left-side secondary tensioner and chain....Where and how do I do this?.....

 

Sorry no one had gotten back to you.

Miss fires on all cylinders on one bank is a sure sigh of a timing chain jump. First, do not start the car again. The exhaust cam can run one chain link off but two links will kill the engine . . . permanently.

Unless they have been changed you have the plastic chain tensioners that are famous for failure.

Remove the valve cover and bump the engine over until the cam timing flats are up and aligned. I might use a socket and breaker bar to manually turn the engine over (clockwise) to the alignment point just to be safe. Remember, two links and you get to open up the engine. The left side will end up almost perfectly aligned while on the right side they will be tilted to the center.

If you find something else you have a cam chain sprocket jump. DO NOT START THE ENGINE!

Check the XK8/R forum FAQ sticky for further information.

 

I have a 2001 XKR which is the supercharged V8 version of the 4.0 AJ27 engine. I had the same misfire you have and it was the secondary cam chain tensioner. This tensioner is not that bad to do it yourself. Take off that valve cover and turn the engine till you see almost all the valves closing, then you will see the flat spots. Tiewrap the chain to the sprockets so it can't jump timing when you remove the exhaust camshaft. My engine doesn't have the cam timing actuator, so I can't be sure if you will have problems tiewrapping the chains. I didn't use tiewraps at all, but I think it's a good idea if you can. I went to the Ford garage and asked them for a secondary camshaft chain tensioner for a Lincoln LS with a 3.9 engine. I paid the man 80 bucks for the new style metal type and a pack of 4 new shorter bolts. You have to replace the 2 bolts because they shorter. I had it replaced in under an hour.
However after doing this, I still had codes showing the misfire. I then took all the ignition coils off and swapped them from bank to bank. The codes went away after this swap. Who knows why. I can tell you that the coils are over 100 bucks a piece so it's worth the effort to swap.
The next thing I have to do is remove the oil pan and remove any broken plastic parts that might be fouling the oil pump screen.

 

Wow....Thanks Guys!!! Looks like I'm a member of the Tensioner club now! lol....Thanks for all the help!!!!!

 

Marc:
I disagre that the "tie wrap method" can be used once an engine shows misfires. That indicates the chains have already jumped a tooth, so a chain timing procedure is in order.

 

Sparkenzap must have been reading my mind! The 'tie wrap' method in this case will only perpetuate the jumped timing.

 

Thanks a million guys. You are exactly right. The exhaust cam was retarded one tooth and that is the real cause of the misfire. The shoe lets go on the tensioner and rides the chain on the way out and shoe horns the chain over by one tooth.

Something else I noticed is that the temperature on the cats are about 100 degrees different while warmin up if the ex cam is outa time.

From a cold start checking side to side from under the car with a $30 temp gun, I quit the test when the left cat got to 300 F. This might help a few other amatuer trouble shooters like myself out there some day.