Keeps jumping time.

Tiny
LANDSHARK1980
  • MEMBER
  • 2002 OLDSMOBILE ALERO
  • 150,000 MILES
Ok, I have tried everything else so here goes. From the beginning. I noticed that when my car was at a red light and I had the break pressed it would idle roughly, I could tell from the viberations didnt have a rythem. I took the car to advanced and The told me after scanning with ODB2 computer that o2 sensor was bad and I had a miss fire on cylinder number 4. (The car is a 2002 Olds alero 2.2 Ecotech engine) So I figured that the 2 were related. My car was due for a tune up anyway so I purchaced new plugs wires O2 sensor "upstream" before cad converter. Installed all no change with Idle. Still was getting misfire cylinder number 4 and bad O2 sensor "figured down stream". Well before I could replace it I was driving down the road and car acted like it ran out of gas. Thinking fuel filter I replaced it, Still no start. While cranking my car to see if it would starn I heard a funny sound under valve cover. So I removed the valve cover and had a friend crank it. In my disbelief I watched as the chain between the DOHC would get slack then loose it get slack and loose it. So I removed the timing cover and found black plastic parts inside that were broken. Turns out it was the timing chain guide and a small piece of it had gotten down between the sprockets and it was being grinded on. Replaced the whole set and no matter how many times I set it It keeps jumping. Honestly I think I just figured out my own problem there is still a piece of plactic in there somewhere causing all ths, because nothing else makes sence. Yes I remembered to prime the tensioner.
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Sunday, May 12th, 2013 AT 7:04 PM

7 Replies

Tiny
HMAC300
  • EXPERT
So what are you asking? Get all the junk out and are all the tensioners new like the chain areany of the gears worn? It may not start because it has bent valves, check your compression
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Monday, May 13th, 2013 AT 7:09 AM
Tiny
LANDSHARK1980
  • MEMBER
Ok the question was why does it keep jumping time, I hypothisied that there might still be a piece of plactic in there somewhere. I checked this morning and nothing was in there.
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Monday, May 13th, 2013 AT 10:37 AM
Tiny
HMAC300
  • EXPERT
As I asked in first replay were all tensioners and guides replaced? The fixed guide as well as upper one? What is your oil pressure or is the tensioner hole plugged and not getting any oil due to crap in the oiling system. Did you replace the bolts holding the sprockets on cams like you are supposed to?
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Monday, May 13th, 2013 AT 12:08 PM
Tiny
LANDSHARK1980
  • MEMBER
Yes I purchased a whole new timing kit that came with sprockets that were keyed a new chain that has timing marks, a new tensioner that uses oil to keep tension on the actual tensioner, a new tensioner and a new guide. Could I have damaged a valve when the car jumped time, causing the cars engine not to be able to decompress. Additional info, I hear combustion in the engine when it turns over but its just one then it jumps time by 3 -4 teeth on the cams. Front cam is set to intake at 2'o clock rear cam is set to exhaust at 10' o clock and crank sprocket white dot is set to 5' o'clock with the crank key at 1 o clock. This is what I went with.
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Monday, May 13th, 2013 AT 1:28 PM
Tiny
LANDSHARK1980
  • MEMBER
Could the timing be wrong, I mean its fool proof if the marks line up on the chain. What about the new sprockets could the wrong sprocket be on the wrong cam. The cam sprockets look identical but they are keyed so it wont go on wrong. I am out of Ideas. Sounds like im getting fire but the exhaust is trapped inside the engine causing the compression to kick back and make the timing jump. Is that even a possibility?
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Monday, May 13th, 2013 AT 2:58 PM
Tiny
LANDSHARK1980
  • MEMBER
What about the cat converter being so clogged that exhaust gas can't pass. These are all just thoughts. I think it's more likely a bent valve or a timing issue, I refuse to give up on this car. It can be fixed I just need to find the right person to bounce Ideas off of. More info, I know more than the average Joe when it comes to mechanics, also I was a Locomotive mechanic for 10 years and have worked on many cars. This is something simple, I'm just over looking it somehow.
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Monday, May 13th, 2013 AT 3:04 PM
Tiny
HMAC300
  • EXPERT
I think you installed it wrong and didn't read up on how to do it. The exaust cam is supposed ot be backed off a little when the chain is installed. I have no idea how you installed it as you've run into a problem and are now looking fo help. I highly suggest you get a manual or rent one on how to do this job then check the compression to see if you have bent valves which when these things go out of time they do. You can' rent amanual here to print for yourcar for minimal cost.
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Monday, May 13th, 2013 AT 3:10 PM

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