Indigent Posted October 6, 2008 Share Posted October 6, 2008 I recently picked up this pathy without a tranny in it, and since my other one's #6 piston gave out, I did a tranny swap. The thing is, I don't know how many miles are actually on this engine. (speedo cable had been disconnected for quite some time according to the prev owner). I decided to do some routine checks recently and timing was one of them. While I was checking the timing, I noticed that it was right on the money at 15BTDC, but it would sporadically jump away from there, to the point that can't see the timing marks any more. It isn't that the light stops working, because it still flashes perfectly. It is as if the timing is just jumping all over the place! My questions is this: What sensors affect the timing at idle, or what other factors could cause the timing to jump? There is no rhyme nor reason to it. It will go for 30 seconds without jumping, then bam. It always comes back, but this definitely doesn't seem right. Any thoughts? indigent Link to comment Share on other sites More sharing options...
Precise1 Posted October 6, 2008 Share Posted October 6, 2008 Wobbly Dizzy shaft? My timing was jumping about, not that bad though, and it was because the center dizzy cap electrode was gone and the unit was firing the cylinders via arcing across the gap to the rotor. Did the idle change when the timing shifted, as it should? Bad spark plug wire? Did you try more than one? Bad pickup/ wire on the timing light? B Link to comment Share on other sites More sharing options...
Indigent Posted October 7, 2008 Author Share Posted October 7, 2008 No change in idle when the timing jumps. When the timing jumps, I wiggled all of the plug wires and no change. I am going to take the whole distributor assembly from my other pathfinder and see if that helps. I know there is nothing wrong with the light. It flashes steadily without interruption. I was wondering if the O2 sensor affects timing at all. indigent Link to comment Share on other sites More sharing options...
unccpathfinder Posted October 7, 2008 Share Posted October 7, 2008 hmm and you're sure the wires are good...it could be possible that periodically you get an interference from one of the adjacent plug wires? in my 95 there is (i think its ignition timing sensor or something) that is in the Dizzy that could be bad...I donno what it does and i dont even think i have the right name there but that could be something with it? I did have my dizzy loosen up one time and it shot the timing to @!*% but it wouldnt return to where it should be...the only thing i can think that would cause it is something with the dizzy... maybe the rotor set screw stripped out and sometimes it gets caught and slips then after a couple dozen or 100 rev's it returns back to where the setscrew is lined up but i think thats a long shot Link to comment Share on other sites More sharing options...
Terrano1992 Posted October 7, 2008 Share Posted October 7, 2008 what other factors could cause the timing to jump? I'm not sure - may be torn harmonic balancer (rubber part inside the crankshaft pulley) is the culprit? It will not affect idle rpms, but only timing marks (when outer part of pulley slips relative to pulley hub). Link to comment Share on other sites More sharing options...
Precise1 Posted October 7, 2008 Share Posted October 7, 2008 No change in idle when the timing jumps. This confuses me, as the engine idle would change with that drastic of a timing change. I'm thinking T1992 may be onto something... B Link to comment Share on other sites More sharing options...
Kittamaru Posted October 9, 2008 Share Posted October 9, 2008 Looking at a diagram of the balancer, I would wager on T1992's idea - check that mate Link to comment Share on other sites More sharing options...
87pathy Posted October 9, 2008 Share Posted October 9, 2008 a bad distributor cap or rotor could cause this. your fire is taken of a plug wire. and if the spark is jumping inside the cap, it could give you a bad reading. other than that the problem could be pretty serious. distributor shaft. or computer problem Link to comment Share on other sites More sharing options...
Terrano1992 Posted October 9, 2008 Share Posted October 9, 2008 (edited) a bad distributor cap or rotor could cause this. your fire is taken of a plug wire. and if the spark is jumping inside the cap, it could give you a bad reading. other than that the problem could be pretty serious. distributor shaft. or computer problem Any REAL timing issue (bad dizzy, cap, rotor, spark plugs/wires, sensors, wiring, computer) calls unstable, rough idle. Slipping pulley affects only timing mark position (which observed with timing light), and not on engine control system. When real timing is too far from 15 BTDC (i.e. timing mark is not visible), engine stalls immediately. Indigent says, his engine idles smooth and stable. So, it's not a problem with ECCS components. I bet to torn harmonic balancer... one of my friends already had similar issue on his Pathy. Edited October 9, 2008 by Terrano1992 Link to comment Share on other sites More sharing options...
Indigent Posted October 9, 2008 Author Share Posted October 9, 2008 I laid down on the ground looking up at the balancer today. The whole crank pulley is wobbling pretty bad, at least enough to be noticed. I am starting to get the feeling that his is a pretty bad problem. If anything, that front crank bearing is not too happy with all of that shaking. I am going to take the balancer from my junk pathy this weekend and see if that affects anything. In a way I hope it is the distributor cap because I just bought it about a month ago, and it is still under warranty. I will update when done. indigent. Link to comment Share on other sites More sharing options...
Terrano1992 Posted October 9, 2008 Share Posted October 9, 2008 I am going to take the balancer from my junk pathy Use special puller ("bird foot" formed steel plate, bolted to pulley hub) for this work. Universal 2- or 3-jaw pullers are not recommended, if you don't want to have two broken balancers instead of one... Link to comment Share on other sites More sharing options...
adamzan Posted October 10, 2008 Share Posted October 10, 2008 I pulled mine off by hand.... Link to comment Share on other sites More sharing options...
Indigent Posted October 10, 2008 Author Share Posted October 10, 2008 Me too. I have never had to use a puller. It is probably because I bought one just for that a long time ago, lol. I have never pulled it off on this new (to me) pathy so we'll see tomorow night. indigent. Link to comment Share on other sites More sharing options...
adamzan Posted October 10, 2008 Share Posted October 10, 2008 Me too. I have never had to use a puller. It is probably because I bought one just for that a long time ago, lol. It's probably because we don't have little girly arms Link to comment Share on other sites More sharing options...
Precise1 Posted October 10, 2008 Share Posted October 10, 2008 I pulled mine off by hand.... We were talking about the harmonic balancer.... I have never had to use a puller. It is probably because I bought one just for that a long time ago, lol. Isn't that the truth!!! Good luck and keep us updated, please. B Link to comment Share on other sites More sharing options...
ankana Posted September 24, 2012 Share Posted September 24, 2012 I had this problem on my 93. the woodruff key and slot had worn to the point that the harmonic balancer had rotated on the crank. Took some very creatiive in-place machining to cut a keyway. But man, was I puzzled about what the timing was doing... How I finally figured it out was to remove the spark plug and insert a small wooden rod into the cylinder and determine actual TDC. At that point the timing marks didn't line up although I still couldn't fathom what was going on until I pulled the harmonic balancer off Link to comment Share on other sites More sharing options...
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