GMC Repair: timing/99 gmc ykon, compression stroke, gmc yukon


Question
I replaced the enire distibutor ( ear for cap broke off) on my 99 gmc yukon(5.7), how to you set timing>? I know on the older ones there is a bypass connector that you unplug, but i haven't found that on this one. I mared the old distibutor, and tried to get back in that spot, but it is off...

Answer
There is no bypass.

Put the enginer on TDC #1 cylinder compression stroke.

Important: Rotate the number 1 cylinder to Top Dead Center (TDC) of the compression stroke. The engine front cover has 2 alignment tabs and the crankshaft balancer has 2 alignment marks (spaced 90 degrees apart) which are used for positioning number 1 piston at top dead center (TDC). With the piston on the compression stroke and at top dead center, the crankshaft balancer alignment mark (1) must align with the engine front cover tab (2) and the crankshaft balancer alignment mark (4) must align with the engine front cover tab (3).

Rotate the crankshaft balancer clockwise until the alignment marks on the crankshaft balancer are aligned with the tabs on the engine front cover and the number 1 piston is at top dead center of the compression stroke.



Align white paint mark on the bottom stem of the distributor, and the pre-drilled indent hole in the bottom of the gear .
Notice: The ignition system distributor driven gear and rotor may be installed in multiple positions. In order to avoid mistakes, mark the distributor on the following components in order to ensure the same mounting position upon reassembly:

  •  The distributor driven gear

  •  The distributor shaft

  •  The rotor holes

Installing the driven gear 180 degrees out of alignment, or locating the rotor in the wrong holes, will cause a no-start condition. Premature engine wear or damage may result.

•  If the driven gear is installed incorrectly, the dimple will be approximately 180 degrees opposite of the rotor segment when the gear is installed in the distributor.

Using a long screw driver, align the oil pump drive shaft to the drive tab of the distributor.
Guide the distributor into the engine.
Ensure that the spark plug towers are perpendicular to the centerline of the engine.
Once the distributor is fully seated, the rotor segment should be aligned with the pointer cast into the distributor base.
•  This pointer may have a 6 cast into it, indicating that the distributor is to be used on a 6 cylinder engine or a 8 cast into it, indicating that the distributor is to be used on a 8 cylinder engine.  

•  If the rotor segment does not come within a few degrees of the pointer, the gear mesh between the distributor and the camshaft may be off a tooth or more.  

•  If this is the case, repeat the procedure again in order to achieve proper alignment.
Install the distributor mounting clamp bolt.
Tighten
Tighten the distributor clamp bolt.

Install the distributor cap.
Install two NEW distributor cap screws.
Tighten
Tighten the screws.

Install the electrical connector to the distributor.
Install the spark plug wires to the distributor cap.
Install the ignition coil wire.
The wire must not touch anything like the dip stick. Rubbing will make a ground/short after time of use.
For V8 engines, connect a scan tool.
Monitor the Camshaft Retard Offset value. Important: If the Malfunction Indicator lamp is turned on after installing the distributor, and a DTC P1345 is found, the distributor has been installed incorrectly.

That is GM procedure. The #8 is cast into the dist. body  around the cap sealing area. If you hold the dist in your hand witht he electrical connector in the 12 oclock position the little #8 will be in about the 3 oclock position.
You'll need a scan tool to set the cam offset. It should be -2 to +2.
I Hope this helps
Good Luck
God Bless
Pawl