.

1997 Ranger 2.3

Can the timing belt become stretched? Could it cause a cylinder 3 misfire code? The belt looked old to me and had many cracks in the smooth back.

I set the timing mark on the harmonic balancer at 0* and looked in the bottom inspection hole and I saw 2 diamonds that were lined up.

I looked in the top inspection hole and saw 2 triangles that were off just a little bit. They weren't off enough as if the belt skipped a tooth, but they were certainly not lined up.

I rotated the engine until the two triangles in the top inspection hole were lined up, then the timing mark was about 5* BTDC.

.

 

If enough of the steel wires that make up the core of the timing belt are broken, the belt can "stretch." But if it is so worn that that is the case, you're long overdue for a replacement. Also, I would think that the side of the belt going over the tensioner migh have some slop in it. Walk or run, but don't drive, to the nearest parts store and get a new belt.

 

However I don't think that would cause a misfire on one cylinder. Problem lies with that cyl. wire, injector, plug compression whatever. kotzy

 

I've never heard of one streching, only breaking.

 

I understand they WILL stretch, but not a lot, usually within the first 5000 miles.

total stretch will be about .015 to .020 or about 1 degree crankshaft. most people never notice anything amiss.

that is why adjuster/idler is adjustable and there is a procedure to check/change tightness of belt.

won't cause cyl midfire, however.

 

This sounds right. If there is any movement, a spring loaded tensioner will take up the slack.

Is the tensioner spring loaded or maybe does it use an eccentric type of adjustment?

 

The tensioner is not spring loaded in the sense that keeps tension on the belt. It is spring loaded and the spring tension is only used at installation time once the tension is set then you tighten down both bolts.

 

Thanks for all of the input. I wonder what could cause my timing marks to be off a little? I may put a new belt on anyway since the one on there is cracked real bad. I can check things better if I take the cover off, too.

The cylinder 3 misfire happened only twice in the last 2,400 miles. The main problem I'm trying to track down is a "missing/rough running" engine after revving the engine a little.

 

IAC valve could be the problem......

 

Timing belts are usually wound with fiberglass or aramid fibers. They stretch very little, a bit as the belt breaks in and a bit at high RPMs. They will break before the belt could ever stretch to a point that the computer could not compensate.

 

.

So, I want to check a little closer if my timing is correct...

Will the timing marks on the cam sprocket and the intermediate sprocket still line up at TDC of the exhaust stroke? Or do they line up only on the compression stroke?

I'm going to put a wooden dowel in the cylinder to determine true TDC instead of trusting the timing pointer, then look at the timing marks again.


Other questions...

How is base timing set/adjusted?

Where is the spout connector?

.

 

The crank gear turns twice for every revolution of the cam gear so yes it will come up on the mark at the top of the Exhaust stroke but the cam will not. I don't think there is a spout on a 97 it use coil packs and a crank sensor talking to the pcm fires the plugs so you really can't time it. I have done literally hundreds of these and have yet to see one that the cam aligns perfectly with the mark when the crank is on the mark on the cover. As long as it isn't off an entire tooh I wouldn't worry about. There are just to many things beyond your control to get it perfect. You have to remember that the entire cover with the timing marks comes off and it really only snaps back in place with just a couple of screws holding it in place. Not very accurate, if you take the cover off the crank gear has a mark on it and it aligns with a notch in the crank seal housing this puts the key way straight up. That is how you set these up when you change the timing belt.