[awbazar]

On a 1996 Olds Ciera SL I noted that the Helm manual for the car shows a diagram of the 3 coils and spark plug wire routing in a way which seems mislabeled. On this car, the coil assembly with the 3 coils is mounted above the cylinder bank near the firewall and slightly to the left when facing the fire wall. This is a waste spark ignition system with shared coils for 1/4, 2/5, and 3/6 cylinders. The rectangular coil tops have numbers for the respective plug wires as follows: 5 and 2 on the left coil top, 3 and 6 on the middle coil top, and 4 and 1 on the right coil top. The 5, 3, and 4 are toward the radiator side of the engine and the 2, 6, and 1 are toward the firewall side. I am surprised that the coil to the right does not have the numbers reversed with 1 toward the radiator and 4 towards the firewall which would make all the front sides odd and the firewall sides even. Since this is a waste spark system, it would seem that reversing the wires on a given coil should not make a difference but there could be some subtle issue. I have always had the wires on the far right coil tower when facing the firewall reversed compared to the numbers shown on the coil top.

The car runs perfectly fine this way and I would like to know if I am making a mistake or this is some sort of mislabel issue. I do not understand why the odd numbers are not all out front and the even numbers are in the rear. Any help would be much appreciated.

The Helm book diagram is a total piece of crap the way it pictures the coil towers and numbers the spark plug wires. If you refer to it, do not get the item numbers mixed up with the spark plug/cylinder numbers. The idiot who made the diagram may have never worked on a car.

[joe_padavano]

Originally Posted by awbazar

I do not understand why the odd numbers are not all out front and the even numbers are in the rear. Any help would be much appreciated.

They should be, but it's irrelevant to your car. The #1 and #4 terminals on the first coil fire at the same time, so swapping the wires on the two terminals of the coil doesn't change anything.

[awbazar]

Thank you for confirming what I suspected. I thought there may have been some subtle polarity issue or some aspect of firing sequense data collection which may have required following the peculiar wire numbering that was printed on top of the coil in spite of the fact that the car runs with the wires in either position. Thank you.