Distributor firing order for a flat cap

SOURCE: in what order do yu arrange the plug wires on the distributor cap or a 1990 gmc 350

1-8-4-3-6-5-7-2 Distributor turns clockwise Number one should be in the 5 oclock position. You should be able to draw an imaginary straight line between the coil tower and number one tower on the cap and the number one spark plug.

SOURCE: spark plug wiring on distributer cap on firing order

here is the diagram for your engine...
click here


Follow the locations on the cap illustration..

SOURCE: spark plug wiring firing order to distributor cap

For the 1988 GMC K2500:
I do not know if you have the 4.3L V6 or the 5.0L, 5.7L or 7.4L V8's however I have included all below:

For the 4.6L V6:
Firing Order:
1-6-5-4-3-2
Cylinders:
......(back)........
'...6...........5...'
'...4...........3...'
'...2...........1...'
.......(front)
Distributor:
......(back)
(+) - screw
..........4
....................3
5
.....................2
....6
.............1
.....................(+) - screw


For ALL V*'s (5.0L, 5.7L and 7.4L)
Firing Order:
1-8-4-3-6-5-7-2
Cylinders:
.......(back)........
'..8..............7..'
'..6..............5..'
'..4..............3..'
'..2..............1..'
........(front)
Distributor Connections:
.....(back)
.....6.....5
3...............7
4...............2
.....8.....1
.....(front)
Rotation:
Clockwise

SOURCE: I need the firing sequence on the 1994 GMC Sonoma

Here is the firing order diagrams for the 4.3 liter V-6 engine and the 2.2 liter 4 cylinder engine, and let me know if you need any help to understand these diagrams, or if you require any further assistance.

4.3 Liter V-6 Engine.



2.2 Liter 4 cylinder engine.

SOURCE: we changed spark plugs &

Here is the firing order diagram for the 5.0 liter (305), 5.7 liter (350) and the 7.4 liter (454) V-8 engines (note position of locking latches/screws between the 3 and 6 and the 1 and 2 terminals on the distributor cap). Let me know if you need the 4.3 liter V-6 engine diagram (hopefully not in a 2500 series truck) or if you require any further assistance.