I took my truck into the dealer to make an appointment to have my timing checked. His response the timing does not need to be checked "the trucks computer automatically checks it and sets it if it is wrong"? Ever hear of this?

That's half right, which I guess is pretty good for a service writer!

The computer does indeed adjust the timing as you drive. It has a certain range of computerized adjustment to compensate for fuel, temperature, etc. However, there is a mechanical "base" setting that is adjusted at the distributor. if the mechanical setting is off enough then the computer can't fully compensate and you may have driveability problems or the like.

I don't know if that's the best way to describe it, but hopefully that makes sense. If you ever have a problem with something like that at the dealer just ask them why the service manual has instructions for setting the timing manually with a timing light!

Thanks

Check out "an interesting observation" under the general forum. My timing was set at 11*, I advanced it to 17*. It made a world of difference in my mileage. I had also taken my "X" to the dealer complaining about performance and they told me it was jsut fine. I don't think they did a manual timing check, because mine definately was out of factory specs.

What should the mechanical "base" setting be?

10, ±2

Actually it's 15 ±2 BTDC.

At least for the 2000 models, I guess they might have changed it.

The emissions control decal installed on the underside of the hood of my 2001 X (build date 5/01) says the spec is 10 degrees BTDC.

Yesh, 2000 = 15 +/- 2, 2001 and up 10 +/- 2

There is also a different procedure for checking and setting the timing on 2001 + trucks and I don't remember what the procedure is for them.

OK, dumb question from me! How the hell do you guys do the stacked + and - ?

Easy, cut ± paste!

Ok here is an update I changed the plugs, cap and roter. Truck ran better I took the truck to the dealer to have the timing checked. He says we will have to do a diagnostic to find out what the problem is...130.00. Ok So I said no way and left. Seconds later I went back and say just check the timing I do not want any diagnostic. So finally he does and it is off 4 degrees. I now need to go find some hills and see if the problem is still there.

There must be a split in the specs for the 2000-2001 on the timing. My title says 2001, build date 11/00 on the door tag and timing specs 15*.

Although this thread was old it was still pertinent. My '03 was about 4* advanced and with the TPS disconnected the RPM was 100 too low @ 600 RPM. I hope for better MPG now! THANKS XOC and its members!

Sorry, to revive old thread (second revival today), but how and what tools do I need to do timing. I'm about to change plugs and was told that I should also check timing. Thanks in advance.

A timing light and basic metric wrenches, don't recall which size wrench.

After seeing this thread I checked mine out last night... It was at 20 degrees . We backed it down to 15... will see if it makes a power/mileage difference. (it's a 12mm wrench by the way)

Oh, and we verified that the computer ASSUMES that you have the timing set correctly. No matter how we turned the distributor, when the engine was idling, the OBD-II port said that it was at 15 degrees. That means that if you don't have it set right then all of the computer controlled stuff (fuel/air mixture etc) will be off!

Oh, a quick explanation on what a timing light is and how it works for those who have never done this (I never had ):

A timing light is basically strobe light - physically it looks kind of like a pistol. The one we used had two alligator clips that you hooked to the battery for power and a third clip that you clamp over the 1st spark plug wire (just like a clamp-on ammeter)... once it is hooked up, you pull the trigger and it starts flashing every time the #1 spark plug fires.

Here's a pic:


So, you take the flashing gun and point it at the harmonic balancer as the engine is idling (the FSM said to unplug the throttle position sensor for this test - which we did).

The strobe effect from the timing light makes the balancer appear to freeze once per rotation right as the #1 cylinder is firing... so you can see the little notches that are cut into the balancer and how they are lining up with the little metal pointer that sticks out of the motor. In my case, the pointer was over the 5th and last notch on the right - indicating that the plug was firing 20 degrees before TDC. So, we loosened the bolt that holds the distributor down and twisted it a little bit while still watching the timing marks with the gun. We experimented with twisting the distributor both directions and figured out which way made the timing marks move toward the right - and when the arrow seemed to line up pretty well with the 4th notch (15 degrees) we tightened the bolt back down, plugged the TPS plug back in, and called it done

Thanks for the info Kaiser. I haven't done mine yet, but I'm sure I'll post another question asking where can find the FSM...hint..hint.

Nissan has a cool website HERE where you can get access to the FSM for like $20.

$20? Am i missing something?

I see "2004 Nissan Xterra Service Manual
$315.00 (USD)"

Buy a one-day subscription and you can view it in PDF format online and save the files.