Which cylinder is number 1 on 96 chevy van 3.4 v 6

If your talking the 02 sensor, it's in the exhaust. Bank one is the bank with the number 1 cylinder and sensor 1 is the first 02 sensor.
The number 1 cylinder shows to be located in the rear bank. If you only have two 02 sensors, that would be one before the cat and one after.

1 8 4 3 6 5 7 2. Odd numbers run down drivers side of the van, even numbers run down passenger side. On the distributer cap 1 is the front right if you're facing the vehicle from the front, go clockwise from there.

Insert the number eight spark plug wire next and route it to the corresponding cylinder. For this example we use a Chevy small block firing order, which is: 1, 8, 4, 3, 6, 5, 7 and 2, rotating clockwise. The wires must connect to the corresponding cylinder numbers which are: left bank cylinders (viewing from the driver's seat) 1, 3, 5 and 7; right bank 2, 4, 6 and 8. Low numbers begin in the front of the engine.

To answer that question you need to follow the plug wire from the # 1 cylinder to the cap. #1 cylinder is the first cylinder located at the far from of the drivers side portion of the engine. (left side) The cylinders are numbered even and odd, so 1,3,5 left and 2,4,6 right. The firing order is also located on the intake manifold directly in front of the distributor.

1-8-4-3-6-5-7-2 The #1 spark plug is the front spark plug on the drivers side and the cylinder location in order from front to back on the drivers side is 1-3-5-7 and on the passenger side it is 2-4-6-8. The ignition rotor rotation is clockwise.

If your Distributor cap is not numbered then replace the new wires, or transfer the old ones to the new distributor cap one wire at a time. Identify the #1 spark plug wire and start from there.

THE FIRING ORDER IS AS FOLLOWS : 1-6-5-4-3-2.
CYLINDER NUMBERS (front-to-rear) :
LEFT (driver side) 1-3-5
RIGHT (passenger side) 2-4-6

To set ignition timing, ensure that engine is at operating temperature, (190 degrees or above), bypass EST (electronic spark timing) by unplugging the single tan wire with a black stripe from the distributor. Ignition timing should be set at 0 degrees or TDC (top dead center). If not, loosen distributor hold down bolt and adjust, then retighten.

For the 2.4L:
Firing Order:
1-3-4-2
Cylinders:
1---2---3---4
(front of Van)
Ignition coil:
1----4
2----3
(front of the Van)

For the 3.0L
Firing Order:
1-2-3-4-5-6
Cylinders:
1----3-----5
2----4-----6
(front of Van)
Distributor:
-----2-----1------
3----------------6
-----4-----5-----
(front of Van)

For the 3.3L:
Firing Order:
1-2-3-4-5-6
Cylinder:
1----2----3
4----5----6
(front of Van)
Ignition Coil:
6---3
4---1
2---5
(front of Van)

For the 3.8L:
Firing Order:
1-2-3-4-5-6
Cylinders:
1---3---5
2---4---6
(front of Van)
Ignition Coil:
6---3
4---1
2---5
(front of Van)

Let me know if this helped, or if you have additional information or questions. Feel free to contact me at FixYa.com!

I sincerely apologize for the late response...Due to the bad economic situation this site has had a substantial (+50%) increase in the number of questions being asked in the last four months.

I am not sure if you have the 1/2, 3/4 or 1-Ton model.
Also Not sure if you have the 4.3L, 5.0L, 5.7L or 7.0L Engine. However I have included all below.

For the 4.3L (6cylinders):
Firing Order:
1-6-5-4-3-2
Cylinders:
6------------5
4------------3
2------------1
(front of vehicle)
Distributor:
coil wire-->
-----6------->............<--------5-------
-----4------->............<--------1-------
-----2------->............<--------3-------
............(front of vehicle)

For the 5.0L AND 5.7L AND 7.0L (8-cylinders):
Firing Order:
1-8-4-3-6-5-7-2
Cylinders:
8-----------7
6-----------5
4-----------3
2-----------1
(front of vehicle)
Distributor:
coil wire-->
-----6------->............<--------5-------
-----4------->............<--------3-------
-----2------->............<--------7-------
-----8------->............<--------1-------
............(front of vehicle)


Let me know if this helped, or if you have additional information or questions. Feel free to contact me at FixYa.com!

chevys firing order is 1-8-4-3-6-5-7-2- at front of engine number one cylinder is on drivers side

Firing order on a six cylinder:

1-6-5-4-3-2

Hope it helps

Mike