89 S10 PU 4x4 4.3L Vin Z, How to set the ignition timing?

[Dayton Marcott]

I'm trying to set the ignition timing on my '89 S10 4.3L 4x4 pickup, but am
not sure of specifics.

I put EST in bypass mode per directions on inside of hood. Timing is
supposed to be 0 degrees BTC. There are three timing mark teeth but no
indication of what degrees they correspond to. Based on pictures of other
timing scales, I figured that the middle tooth was 0 degrees and using my
timing light on the number 1 plug, set the timing to correspond with the
middle tooth. But the engine pings excessively on that setting. Before I
changed the timing, the setting was highly retarded, way off the scale, like
someone set the timing without the EST in bypass mode. I can experiment and
see what works better, like setting the timing to the first timing tooth
instead of the middle tooth, but I'd like to know for sure. Anyone know?

Thanks,
- Dayton

[DW]

0 TDC is the big wide tooth on the pointer. Be advised that the 4.3L has two
marks on the harmonic balancer. Disregard the first one and use the second
to set 0 TDC.

"Dayton Marcott" <dayton....@worldnet.att.net> wrote in message
news:_vUq5.10063$Q36.7...@bgtnsc07-news.ops.worldnet.att.net...

[DW]

Nice photo.  The 0 degree timing mark is at "D".  Your harmonic balancer is the round wheel on which your timing marks are located,(mounted on the crankshaft). It is also often referred to as a vibration dampener. As I stated before the 4.3L has two grooves.  Use the second groove for base timing(according to engine rotation).

"Dayton Marcott" <dayton....@worldnet.att.net> wrote

Thanks for the reply. I don't see a big wide tooth. Below is a picture of my timing marks:

 

<jpeg snipped to conserve bandwidth>

 

The leftmost mark (A) is soiled and doesn't show up quite as well, but is the same size as and symmetrical with the right mark (C). On the far right is what looks like a receptical for a magnetic probe. I checked the timing before making any adjustments. It lined up with point E, the left side of the plate supporting the magnetic probe holder. Not well visible here is a small point at position D.  I had originally set the timing at point B, but had a LOT of ping. Then I changed it to C but still had quite a bit of ping. I now have it set at point D, and nearly all the ping is gone but there seems to be a slight amount once in a while. I don't know what a harmonic balancer is.  So with this picture, can you tell me where 0 TDC is?

 

- Dayton

 

 

 

"DW" <D...@HOME.ATT> wrote in message news:RWUq5.10086$Q36.7...@bgtnsc07-news.ops.worldnet.att.net...

[Dayton Marcott]

Got it! Thanks. I have a small Chilton's repair manual for S10 pick-ups for
'82 to '91, which by necessity makes some generalizations. Do you know of
any detailed manuals specificallly for my model and where I might get one?
It would be nice to have a good reference.

- Dayton

[DW]

Probably the best all around manual for the price is the Haynes manual,
available at most discount parts stores. The number for the manual for your
rig is #831.

"Dayton Marcott" <dayton....@worldnet.att.net> wrote in message

news:nDYq5.578$U41....@bgtnsc05-news.ops.worldnet.att.net...

[High Sierra]

I would recommend having both a Haynes and Chiltons. They both have strong and weak points. I like the photo's in Haynes, Chiltons has drawings.

Chiltons has much more detail in the wiring diagrams.

A GM shop manual for the specific year would probably be best.

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"DW" <D...@HOME.ATT> wrote in message news:oIZq5.687$U41....@bgtnsc05-news.ops.worldnet.att.net...