Is the ignition supposed to stay exactly at the 10* BTDC mark (3VZ-E) or will it fluctuate plus or minus 2 degrees? I was trying to get it to stay with the terminals jumped, but it would jump to an occasional 12* or 8* and then up to 15*. Does this indicate a bad distributor housing or something else? Ignitor? The plugs, wires, distributor cap and rotor are only about 15K miles old. I also have a pinging problem (when running premium gas), which i guess is related to the timing jumping way to 15* BTDC. Any input is greatly appreciated!!

 

I also don't see a 'perfect' stability on the 12*mark where I have set it...it sometimes jumps around a little...but I ignore the occasional spikes and focus on the main mark where it spends the vast amount of time as the actual setting. It's not an exact science, you should be able to interpret what your timing light's telling you...I'm subscribing to this thread, curious about whether other 3vze engines are giving a rock solid timing light reading or oscillating a bit like mine.

 

No, misadjusted TPS or gum build up in the throttle body holding the throttle blade partly open.

 

Well, I just cleaned out the Throttle Body this weekend, and all of the TPS readings are within spec. I have a couple of friends that have gen 2 4Runners with the 3.0. One of them has a rebuilt engine. I'll put my timing light on his 3.0 and see what I get.

 

I finally got around to comparing timing readings. The ignition timing jumps around a little bit on my friends rebuilt rig too. I dropped the idle speed to 400rpm on my rig and the flash became steadier at the 10 degree mark. I think the fact that my timing light was made in the 70's and it is pretty old might have something to do with it too.

 

Timing jumps around. Nothing to worry about. Unless it is running like complete crap. Timing gun has nothing to do with it. Just jumper the pins. set the timing and you are good.

 

yeah i dont know where mine is its all the way to btdc as far as it will go and yes my timing is right on with the rotor and cam but yes is does jump around

 

It's a mechanical system, subject to "jitters" as teeth engage and the distributor gets turned.. Crank trigger systems are much more accurate.