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Discussion Starter #1
Hi folks,

I changed the timing belt and harmonic balancer on my 2000 V6 Xterra a while back and last night decided I should re-check the ignition timing as I'd not done that yet.

Using the full rotation of the distributer I can only barely get the timing mark on the scale on the (new) harmonic balancer pulley with the TPS connector unplugged as per the service manual. Otherwise it is way off towards the advanced side, and the closest I can get it is like 19 degrees BTDC. Otherwise it is way out around maybe 35-40 degrees BTDC.

I'm pretty sure that's not accurate as the car is running fine and not pinging. I tried to put the distributer back where it probably was by matching up the dirt marks on the head with the distributer base and checked it with the TPS connector plugged in and its around 16 degrees BTDC (in normal operating configuration, not "timing mode" with the TPS connected.)

Would I be correct that I should be seeing it at 15 degrees BTDC with TPS unplugged and (presumably) 0 degrees or so with it plugged in and at low idle?

I'm pretty sure I never had this problem before the repair work (as in I was able to time/check timing on it before) so I'm afraid I either got the camshaft that drives the distributer a tooth off or this Dorman harmonic balancer is stamped wrong. I can't imagine having gotten the timing belt install wrong because I checked it five times in two different ways (lining up the marks and counting teeth between them. Also it seems to run pretty well for a camshaft being a tooth off! Maybe I need to yank the pulley?

I took the pulley bolt out and felt for the keyway and referenced the timing marks to the keyway and they do seem to be in the same spot as the marks on my old OEM balancer. I can't be 100% sure though without pulling it off.

What do you think? Balancer stamped wrong? Camshaft off? Distributer rotor a tooth off? Operator error?

Does anyone know what a reasonable timing is with the TPS connected at idle on a 2000 Xterra?
 

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Discussion Starter #3
The dist is one or two teeth off ,pull and reset .
I thought about that but I never pulled the distributer off so I'm not sure how it would have gotten that way, and if it really is advanced like 35 degrees, it runs pretty well for being that way.

I pulled the damper and compared the old and new. The new one is about one "notch" off on the timing marks, in that 5 degrees BTDC is actually TDC if the old one is correct. Not enough to make up for what I'm seeing.

I undid the bolt and turned it all the way to the fully retarded position with the TPS unplugged (which reads about 19 degrees on the scale and would equate to around 14 degrees on the old harmonic balancer. It runs but as you near that mark the idle speed drops quite a bit. That's where it "should" be but it just seems like a stretch.

I'm also confused about why the timing is ~15 degrees at idle with the TPS connected and up in the 30s-40s with it unplugged. I thought you were setting the base timing, and the ECU advanced it from there. It seems like when I unplug the TPS the timing goes fully advanced instead.
 

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Discussion Starter #4
To further complicate this issue:

I just discovered my ScanGauge corroborates the behavior with the TPS disconnected. When I have the TPS plugged in the ScanGauge shows a timing of around 15 degrees BTDC which the timing light mostly agrees with. When I disconnect it the timing goes to around 35 degrees at idle on both the ScanGauge and the timing light.

With the timing set as close to 15 degrees by the light as I can get the engine takes a while to turn over. I have got to be doing something wrong.
 

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When you did the timing belt you have both cam wheels and HB sinked but not with the location on head arrow or pan arrow , this put the dist out of sink ,you have two choices adjust the dist by moving to the correct tooth or reline the timing belt .Most engines are missing the pan arrow and it makes it difficult to line up , the mark on the head or pan arrow is what sinks the dist.
 

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Discussion Starter #6
Hm. I'm not sure I understand. If I got the camshafts synced to the crankshaft, shouldn't the distributer be synced to the crankshaft as well (since I never took the distributer off?)

Even so I will check it out. I'm just getting worried I did get drivers-side camshaft out-of-time.
 

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No there are 5 points to line up 2 cam marks 1 crank mark and one of the following ether the mark on the head or the mark on the oil pump housing.You have only done 3 of 4. Remember the mark on the crank you lined it up with the mark on the belt ,than the factory put a mark on the oil pump for you to line all three in a straight line but guess what the factory messed up and forgot to add the mark on the oil pump housing. Read thru DYI on belt replacement look at the foto he says is not a Xterra he used a pickup engine (close) but the reason maybe he did that was it has the mark on the oil pump housing you can see in the foto. This mark is how you line the dist with crank and cams. You were close but not on because there was no mark to check.All you need to do is pull the dist move one or two teeth and you good to go.
 

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Discussion Starter #8
Haven't had a chance to pull the distributer yet because I usually have 5 minutes of daylight left when I get home in the evenings, but I realized stupidly that I'm trying to set the timing while it's idling at 1,500 RPM.

With the TPS in it idles normally, around 800. If I run it unplugged it it jumps up to 1,500 and will not come down for anything no matter what I do. I have the screw backed all the way out. That has me quite confused.

I'm going to try to check the IACV tomorrow if I can get home before dark (which is like, 5:30 PM here right now). I feel like I need to fix this out-of-whack base idle speed issue before trying to set the timing since even with the TPS unplugged the timing map follows engine RPM.
 
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