Timing

[Rocko]

I replaced my distributor, which was pretty easy. My question is, the FSM recommends 10* btdc. I set this and the motor sounds good, but it just isn't as responsive as it was. Now, like an idiot, I failed to see where it was set before I replaced the dizzy, so I'm wondering if anyone knows where this motor really likes the timing set? I thought I read somewhere here that said 15* btdc.


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[Muadeeb]

I think the 2000 wanted 15*, but the 2001 - 2004 wanted 10*. Full procedure: http://www.nicoclub.com/FSM/Xterra/2001_Xterra/ec.pdf#page=644

 

[Rocko]

Ok, my motor is not the stock motor. It could very well be a 2000 in my 2001. I need to find out for sure.


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[Rocko]

Went ahead and reset the timing to 15* btdc. She perked right up for me! So I'm going to guess and say that I have a 2000 motor. Which would explain that weird wiring harness with all the open plugs that I asked about when I first got it. I would assume that the motors would take 2 different ECMs.


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[TJTJ]

Went ahead and reset the timing to 15* btdc. She perked right up for me! So I'm going to guess and say that I have a 2000 motor. Which would explain that weird wiring harness with all the open plugs that I asked about when I first got it. I would assume that the motors would take 2 different ECMs.


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The ECM should be for the truck not the engine really.

Its SUPPOSED to be the other way around, but, in practice, especially with a newer engine in an older truck...

If you put the new motor in, IT will have more plugs and wires than the one it replaced...and those go into your TRUCK's harness, to talk to the ECU, etc....


If your TRUCK's harness doesn't HAVE a receptacle for the doohangy off the ENGINE, well, the engine doohangy just ends up hanging there with no where to go...but, the ENGINE is mostly mechanical, and as long as its sent the same spark and fuel the OLD engine would have been OK with, you're good to go, and, no dash lights go on, etc.

If you get the ECU for the new ENGINE, that new ECU is LOOKING for feedback from all sort sof stuff on the NEW engine that was not on the old engine......

..except the TRUCK's wiring harness doesn't HAVE a way to connect the engine's doohangies to the ECU..as those were not IN the older harness.

So, what we have here is a "Failure to Communicate"....and the dash lights go off because the new ECU is not getting what's its looking for.

IE: Use the ECU for the TRUCK, not the engine...for a new engine in an older truck.

 

[Rocko]

Well, after about 200 miles of running pretty good, its started spitting and sputtering again. Especially if its cold, you cant get over 1200 rpm. The check engine light is back on. I dont have a scanner right now so Im probably just going to leave it sit till then. Not a very good christmas present to myself. Probably gonna hit the dealer up.


TJTJ, I think I have a 2000 motor in my 2001.

 

[Cyclemut]

Either way, which mark on the harmonic balancer did you use for 0°?

The difference between the years (for timing purposes) is which mark Nissan wanted you to use for 0° (TDC). They used the same harmonic balancer, so you can use either spec for timing, as long as you use the correct 0° mark as reference. Nissan really fubar'd that up on the 1st Gens.

I use the mark all the way to the left (passenger's side) and set my light to 15° (for my altitude, I actually use 17° [adding in 2° for altitude] and can realistically go up to 19° as the spec is 15° +/- 2° [then adding in the 2° for altitude, then the 2° for the +/-, see?]) and set the pointer on the far left mark.

One version of the book (just for knowledge, not to confuse anyone) used the far left mark as the 5° ATDC mark, the next mark to the right as 0° TDC and then the following marks as 5° BTDC, then 10° BTDC, etc. Then later years of the book, for the next years, it went to the marks like what I use. They had to do this because of the stickers under the hood stated 10° and 15° for the later years.

So I'd set the timing as I do and see if it keeps things perky. Who knows, perhaps you left the dizzy clamp bolt loose or it came loose.

 

[Rocko]

I did it the way the book said. Are you saying its wrong?

 

[Cyclemut]

No, not necessarily wrong, but there are easier ways of doing it. Did you disconnect the TPS at the throttle valve when you checked the timing? Are you using a timing light with an advance feature or a standard light?

The procedure I outlined did not include disconnecting the TPS, I should have also stated that. And the vehicle needs to be fully warmed up too, so the wax pellet in the throttle valve isn't keeping the idle up. Other than that, using the procedure in the book is a sure fire way to get it done, as long as it's followed closely.