Help: 95 2.3 ranger no spark 2&3 intake side

[SvoRx7]

I know this has been covers extensively but having searched and searched still haven't found a solution for this. Okay 95 2.3 ranger with the waste spark system, replaced both coils plugs and wires and there is no icm on the 95 I'm getting spark on all other cylinders, just not 2&3 intake side. The truck barley runs unless it has 1/2 throttle, also backfires out of intake. On the coil pack pigtail for the intake side I have my 12v on the middle wire and the voltage goes up and down on the other two, could this be a pcm issue? I have briefly checked the wiring and nothing seems to be out of place.

All help GREATLY appreciated.
Thanks guys

 

[SvoRx7]

Okay just an update here, it turned out to be a combination of 3 different things, for the first time ever I was sold a bad coil from the part house, the maf was bad, and the iac was bad. And btw I had no idea if the iac went out it would waaayyy over rev the motor I had a svo mustang for years and still the 2.3 is surprising me. Thanks so much for the help guys.

 

[RonD]

Glad you got it figured out.

If IAC failed open, yes RPMs would be high.

The 8 spark plug 2.3l/2.5l Lima engines, only use the Exhaust side coil and spark plugs when starter motor is turning engine over.
Intake side coil and plugs will start to fire when crank RPMs are around 400 or higher.
So just a heads up when testing for spark.

1995 was first year the ICM(ignition control module) was part of the computer, Rangers got the new 104 pin EEC-V computers in 1995, old EEC-IV was 60 pin

I think they still only spark on exhaust side while cranking but haven't tested it, 1994 and earlier are for sure that way

The Ford coil packs work like any other ignition coil
The coil gets 12volts with Key ON, middle wire on this coil pack

The Ground wires for the 2 coils in this pack are the other two wires, outside wires.

When you power up a coil of wire around a metal core it builds up a magnetic field, if you CUT the power the field collapses.
If there is a second coil of wire in that magnet field it will pulse voltage out when power is cut.
The coil of wire that gets the 12volt power is called the primary coil, other coil is the secondary coil
If primary coil has 100 turns around the metal core and secondary coil has 10,000 turns then the 12volt collapse causes a low amp High Voltage pulse to be sent out on secondary coil, that's what goes to distributor and/or spark plugs.
So an ignition coil is a voltage multiplier.

Since the days of points in a distributor it was easier to cut the Ground on the coil to cut power, less chance of 12volt shorts to ground that way.
And that hasn't changed.
But now instead of mechanical points opening and closing to power up and then cut power(Ground) to the coil they use transistors.
So each "other wire" on the coil pack is hooked to a transistor that the computer is Grounding and unGrounding to "fire" each coil in the pack.

Waste spark system has been used since there were gasoline engines, it is one of the first spark systems and any single cylinder engine still uses it today, each spark plug fires when it's cylinder's piston is at Top Dead Center(TDC).
Ford uses the 2 coils in one pack to spark the 4 cylinders, 1 and 4 pistons are at TDC at the same time so both spark plugs are on 1 coil in the pack, as are 3 and 4 since they are at TDC at the same time.
Since it is a 4-stroke engine one cylinder will be on compression stroke and the other on exhaust stroke when spark plugs "fire", no not for emissions purposes, just simpler way to do it.
And on the dual spark plug setup both spark plugs, exhaust side and intake side, "fire" each time piston is at TDC.

Except when cranking engine,