[knockout_jab]

I have been having trouble with my timing belt on my '99 zx2. Was driving along one day and it was if someone had reached over and turned my car off while driving it. Got it home and looked at the timing belt. It had started to fray at the edge so me and my buddies figured it jumped time enough to shut off. After it was all said and done, we retimed it with a new belt, changed fuel filter, put new spark plugs in and replaced the camshaft position sensor.

Ran good for about a week and the exact same problem happened again. Got the fellas together again and we come to the conclusion it jumped time because the belt wasn't tensioned enough (though I believe it wasn't loose enough to jump time again). We retimed it a second time and tensioned it to a point that being too loose is completely out of the question.

Drove it for about 50 miles and it happened again. I am completely clueless now. The belt doesn't seem to want to ride all the way back on the cams like it should and wants to move about a 1/4" off. I don't believe that this is the cause of the timing problem but may be an indication of why it keeps jumping time. Has anyone ever heard of a bad cam gear or crankshaft gear causing the belt to ride just slightly off and jump teeth? or is there something completely different that I'm missing?

 

[kikoy]

you might be having a bad tesioner.....if i was to do a timing belt id replace the timing belt, belt tensioner(for the timing belt), water pump(just to make sure).....and also torque all bolts and nuts to proper spec.....

 

[sethxtreme]

your actually supposed to replace the tensioner anyways, and the reason everyone says to replace the water pump is because, your right there, why not do just a little more work i.e. preventive maintaince. Also as an alternate route for the tensioner, if your strapped for cash, you go to Ford and buy yourself a tensioner pulley bearing. By replacing this you save about 30 bucks, and then for added quality buy a Gatorback belt, they tend to be just a lil bit stronger, and tend to be of a higher quality. On a second note, you threw the timing belt while the car was running? im not sure what motor you have, im guessing its the DOHC zetec...and maybe its an interference motor? im not sure. But make sure that you use
Loc-tite on those bolts for the tensioner, only because they may come loose just enough for the tensioner to adjust tension due to engine speed, i.e. loosen while at 3500 rpm as opposed to 800 rpm. hopefully i made sense

 

[knockout_jab]

I asked around and a lot of people said the same thing: check the tensioner to see if it went bad. I took a look at it, reread the entire section on the timing belt in the Haynes manual, and retimed it one more time. A couple of us came to the conclusion that even though it makes sense to tighten the belt down to a point that it's as tight as it could be, it also makes sense why you wouldnt' want this too. Like i said, we looked over the manual and it says to adjust the tensioner to the point that the adjuster is matched to the mark on the engine. In hindsight, if the tensioner is adjusted past the optimal point, there isn't enough automatic adjustment for the belt to remain tight during higher rpm's. The belt doesn't seem to be riding off anymore but time will tell. i'm not planning any major roadtrips anytime soon. But hopefully overtightening was the only problem.