Timing mark way off...

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I checked the timing on an 01 Altima, the timing marks jump kind of erratically. When they do stop moving I can see I'm way off where I am supposed to be. I'm roughly at 5 degrees ATDC and TDC, I can see the other marks to the right, I'm supposed to be advanced way to the rightmost mark at 20 degrees BTDC.

Does this sound like it's even possible for it to be off this much? Could the timing light be defective? The car idles like garbage and I did take the distributor off a long time ago to change an o-ring but I made sure to put it in the correct/keyed direction and I marked a sharpie mark before I did it on the valve cover and the dist. housing. That sharpie mark is still there and still lines up.

The timing light was set to 20 advance to match 20 degrees BTDC and I was that much off on the timing marks. I set the dial to below zero on the timing light which means almost no advance right? This made the timing marks on the balancer line up to where I should be, 20 degrees BTDC.

Does anyone know if this sounds like something seriously off? Does the distributor even allow me enough rotation to set me where I need to be? Should I do it? If I rotate the distributor can I affect the timing enough to destroy the engine?
 
I actually followed that service manual when I did this, I did disconnect the TPS when I did the test.

If the chain is worn causing this, would I also be guaranteed to have low compression? Or could a worn chain have normal compression? My gut feeling is it would always have low compression but not sure.

Can I "retime" the engine in its current state?
 
You mentioned you have a distributor, you can check the slop in the chain by observing the distributor shaft/rotor and rocking the crankshaft back and forth with a breaker bar, taking up the slack and noticing when the distributor shaft just begins to rotate. If you reference the marks on the balancer, you can determine the degrees of slack. A slipped harmonic balancer would show the timing (indications)way off but wouldn't cause the timing to jump around. If you jumped even one tooth, the engine would run poorly and compression would be affected as you inquired..If you have a belt, just check for looseness as it is not advisable to rotate the engine backwards with a timing belt. A misfire can create havac as you describe.
 
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Originally Posted By: NoNameJoe


The timing light was set to 20 advance to match 20 degrees BTDC and I was that much off on the timing marks. I set the dial to below zero on the timing light which means almost no advance right? This made the timing marks on the balancer line up to where I should be, 20 degrees BTDC.


Can you get a simple/ stupid timing light without a built in advance gizmo and stick that on there? Any given Saturday will have one at a yard sale for $2. I would worry that since timing lights aren't as popular as they used to be you have an old one that drifted calibration. A simple one doesn't have calibration to drift.

IDK how to time Nissans specifically but they should have a zero mark usable for setting the timing belt (and verifying TDC) and a "regular idle time" mark.
 
Set the dial to zero and follow the FSM procedure. All factory timing is done with a zero delay light.
 
I plan on doing a test later today where I line the balancer at TDC with the 1# piston at TDC on compression and the distributor rotor. Will report anything I notice.

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Set the dial to zero and follow the FSM procedure. All factory timing is done with a zero delay light.
But the service manual says to do it at 20BTDC and to set the timing light to 20BTDC...

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You mentioned you have a distributor, you can check the slop in the chain by observing the distributor shaft/rotor and rocking the crankshaft back and forth with a breaker bar
Plan on doing this later today as well. Would this prove anything though if the engine has a tensioner that takes up the slack? What would be a definitive way to tell the chain is worn no matter what?

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Can you get a simple/ stupid timing light without a built in advance gizmo and stick that on there?

I can't but I did buy a second timing light today to compare the results with
whistle.gif
as well as a nice white paint marker to clean up those timing marks.

Something really important I just remembered: I have a P0325 also for the bad knock sensor. I just read that the P0325 can cause the timing to retard which would probably explain why I'm not seeing the 20 advance and seeing TDC instead maybe? Could the bad knock sensor itself cause a misfire by changing the timing? Or should the engine run fine without misfires at TDC as well? If I compression test now I should see the same compression with the wrong advance right? It shouldn't affect anything since the advance is only used for the spark? The compression is compression no matter how the timing is as long as the valves are synchronized correctly with the piston on the upstroke?
 
Originally Posted By: Silverado12
I have seen bad harmonic balancers throw the marks way off and affect the way the car vibrates while driving. Something to check anyways.


That's what I was going to recommend but I'm not familiar with newer cars. The old stuff I work on have harmonic balancers with a pressed on outer ring that slips over time. The only thing holding it on is a thin strip of rubber that gives it the dampening effect.
 
So the results are if I line up the #1 piston at TDC on compression I get TDC on the timing mark on the balancer and the distributor rotor points to post for number one wire on cap.

For the slack test I lined the pulley up at about TDC by turning clockwise. Then I had a helper watch the rotor while I turned counter clockwise. I had to turn to about 20 BTDC for the rotor to start moving. Could this be right? Is there any other test I can use to substantiate what I'm seeing here? Like compression or anything?

FWIW I think I also discovered that I didn't pull the throttle position sensor. When I pulled the harness for the sensor I hooked up my scan tool and realized I can still get the throttle position reading when I push on the pedal. So I went and pulled the other harness right next to it, the two look identical and both harnesses plug into the throttle position sensor. After doing that I could no longer get the throttle position on my scan tool.

Problem is if I pull that "correct" harness the car won't start so how am I supposed to time it?
 
Welp, false alarm. I went back and read the service manual closely. The step after unplugging the TPS says to "rev" the engine 2 or 3 times. I realized that as soon as you start the car to prevent the engine from stalling you have to rev it. If you rev up and down 2 or 3 times it idles fine afterwards.

Checked the timing and it's right on 20 BTDC and it stopped jumping around too. Everything's good I guess! So I did unplug the wrong sensor the first two times around. The scantool was right with the TP% reading, helped me figure that out.

Car only has 90000 miles on it for a 2001 and has had regular oil changes, I hope the chain isn't bad. There's no timing problem.
 
Originally Posted By: NoNameJoe
So the results are if I line up the #1 piston at TDC on compression I get TDC on the timing mark on the balancer and the distributor rotor points to post for number one wire on cap.

For the slack test I lined the pulley up at about TDC by turning clockwise. Then I had a helper watch the rotor while I turned counter clockwise. I had to turn to about 20 BTDC for the rotor to start moving. Could this be right? Is there any other test I can use to substantiate what I'm seeing here? Like compression or anything?

FWIW I think I also discovered that I didn't pull the throttle position sensor. When I pulled the harness for the sensor I hooked up my scan tool and realized I can still get the throttle position reading when I push on the pedal. So I went and pulled the other harness right next to it, the two look identical and both harnesses plug into the throttle position sensor. After doing that I could no longer get the throttle position on my scan tool.

Problem is if I pull that "correct" harness the car won't start so how am I supposed to time it?


Twenty degrees is too much slop. Anything above five degrees is too much. Sounds like you checked correctly.
 
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I'm beginning to wonder why it had that slack.

If there was that much slack, why didn't I see it and why was the timing perfect when I did the check according to the FSM with the TPS disabled?

If there was slackshouldn't the timing be off no matter what?

Basically I'm trying to reconcile the slackwith the fact that the timing looked correct when I ended up finding the right harness for the TPS to unplug.
 
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