wbthornton88

I have just rebuilt my 95 3vze 4x4 pickup because a head gasket failed. I am now running and everything sounds similar to the way the truck ran before the rebuild. The strange thing is when I set the ignition timing and adjust the truck idle to 900 rpm the ignition timing reads like 30-35 degrees before tdc. If this helps I had the heads and block resurfaced and I don't know if that would be causing it or not. Im sure it could be though because just a small adjustment at the distributer or the idle screw changes the ignition timing reading a noticeable amount.

The MAN

the disty was installed at the correct position right (gear inserted while engine at TDC and matches it)? are you also jumpering the diagnostic connector pins while setting up the base timing?

MudHippy

First, 900 is 100 rpm above the specified 800 rpm for setting the timing. So if it's advanced past stock @ 900 rpm that's normal, just not that much.

Second, what is the initial timing set at?

wbthornton88

I set the cam timing at 0 tdc if thats what you mean by initial timing. Am I supposed to jump the diagnostic terminals when checking/setting ignition timing?

MudHippy

Initial or base ignition timing is what you are setting when you "set" the ignition timing. The terms initial and base refer to what's called the ignition timing curve(as if shown on a graph of degrees advanced over engine speed/rpm). It's the starting point of the curve at idle rpm, the ending point being at/near max rpm. The points comprising the curve between being the ° BTDC @ each rpm.

Here's an example of what a timing curve looks like.


Apparently nobody's showed you the FSM yet. See the Engine Mechanical Tune Up section for the ignition timing adjustment procedure, pages EG2-25 & 26.

http://personal.utulsa.edu/~nathan-buchanan/93fsm/

So what is it set at? Because at 900 rpm it shouldn't be 30°-35° BTDC. Unless it was fully advanced, and even then I don't know if that's possible. What are you using to set the timing, as in what kind of timing light. The digital kind that you look at 0° with the actual timing angle on a display on the unit? Or the regular kind?

wbthornton88

I'm using a regular timing light that hooks to #1 spark plug and battery. I forgot to jump TE1 to E1 terminal. Last time I got a correct reading I had these terminals jumped. I'm confused about what the tachometer does in the online FSM could someone please explain this?