My 93 talon keeps jumping timeing. I'm going to replace the timing belt and tensioner. My question is has anybody ever had a problem similar to this before, and what was the problem. I just want to make sure there isn't some simple thing that I'm overlooking.

YOu should replace the timing belt on general principals, but I assure you it isn't that. If, god forbid, it is your timing belt you've already cashed the head and probably the pistons, so i really doubt its that.

Have you done the basics, like boost leakdown testing and looking for a vac leak? How does it idle?

ALso, are you running an SAFC and/or a logger? care to post a log?

just to make sure, is the belt physically moving, or just the "timing" that the ecu is getting is changing?

If the timing belt is actually skipping a tooth, then you definitely need a new belt and tensioner. Possibly some new tensioner pulleys or they may need tightening. The torque procedure on those pulleys is kind of unique, I don't know if I could do it with the engine in the car.

Is the belt actually walking back and forth on the cam sprockets? Or does it just rise up and skip a tooth?

If the timing is just getting messed up, maybe the CAS on the left side of the head is loose?

Originally posted by thedawg
If the timing is just getting messed up, maybe the CAS on the left side of the head is loose?

probably a better bet than the belt itself..

How are you watching the timing? Logger?

It cycles through as you rev it so the number is always changing kind of like the O2's at idle. How are you viewing this problem? Or did I misread it and you are using the timing light often to check base timing?

ok sorry i should have gone into more detail, but i was in a hurry. Basicaly the timing has physically skipped a few teeth. It isn't computer related, I didn't mean to imply that. I'm not sure but i think that the exhaust cam actually got retarted or something to that effect. I'm not for sure on that, but either way, I don't believe the valves or pistons were damaged at all. I never heard any ticking from valves slapping pistons. And are the pulleys a problem area? Thanks for the feedback, keep it coming.

Oh and just incase it makes a difference all I've done to the car is an apexi N1 downpipe-catback, mbc set at 14psi, safc, rewired fuel pump and K&N air filter w/ open can.

EDIT: and boost and egt gauges

may be a bad tensioner or a stretched belt. do you know when these parts were last changed? when i changed my tbelt, my tensioner was faulty and while driving, i heard this flopping around like crazy. it was my tensioner spinning with the belt moving. :nono lucky i didnt kill the car. *phew*

No I really don't know when they were last changed, so I guess that means it's time to replace them. I'll try that and let you all know how it goes. Thanks for the help. Oh and also on the SAFC does that little knock sensor on there do any good. By that I mean is it every accurate, and is there a point where you can tell it has too much knock? I never really understood that. Thanks again.

there isnt a such thing as "too much knock". any knock is too much IMO although sometimes it may be unavoidable to have a few counts.(gas types, weather conditions, engine conditions, etc) as far as how accurate the safc is, i do not know. my car is pretty stock as of right now so i dont have any fuel mods yet. :-( soon though......}(

Well I realize any knock is bad, but by counts of knock are you referring to the Hz or am I just dumb? I really don't understand anything about the Knock monitor on the SAFC.

me neither, since i dont have one. anyone else care to enlighten? jeff?

anybody?

Originally posted by sd240
Well I realize any knock is bad, but by counts of knock are you referring to the Hz or am I just dumb? I really don't understand anything about the Knock monitor on the SAFC.

knock monitor on SAFCII is bogus IMO, just like the boost readings I get from my profec B (spec2). According to the profec, i'm only boosting 15psi. According to my boost guage, i'm more like 18-20, depending on air temp, engine conditions, etc. :-o The profec is also terrible at reading spike---but my point is i'm of the opinion that "all in one" functions sacrifice quality/reliability of readout to give you all that extra stuff in an affordable package. Look at what happens with the "blue wire mod" on the SAFC, if you wanna see my point...

you are talking about a 1g, right? if you are talking about a 2g, then there is no knock count at all (that you can see, at least), unless you use DSMlink (I think)