2 cyls not firing

[keeter57]

We have just installed a engine in our 98 explorer (4.0 sohc) we have no fire to 2-6 cyls,we have checked wires, coil ,swapped coils,no fire coming out of coil for 2-6 could this be a computer problem?

 

[97expV8]

that model uses a distributor right?...if so I would double-check the positioning of it and check spark at distributor cap to eliminate wire to plug issues first.

Disregard the comment about distributor. Check at the coil-pack like 2000StreetRod says below.

 

[2000StreetRod]

2 & 6 sparkless

I assume that you swapped in a known functional coil pack.

Spark plugs #2 and #6 use the center section of the ignition coil pack. Both plugs fire at the same time - one on the compression stroke while the other is on the exhaust stroke. If either plug or plug wire is open then both plugs will not fire. Make sure neither plug wire is broken (measure resistance), that the plugs are not broken and that they are gapped correctly (0.054 inch). Make sure the boots are seated on the plugs. If everything checks out then one of the plugs could be defective.

Check the primary electrical connector at the coil pack. My wiring diagram doesn't indicate which of the wires is for the center coil. Make sure none of the pins are bent or pushed back. Then check the PCM pins. Either pin 26, 52 or 78 is the control for center coil. Make sure the pins are not pushed back and the connector is on tight but not too tight. You can also check continuity from the PCM connector to the coil pack connector.

The PCM is fairly reliable. I would thoroughly check all electrical connections before replacing the PCM.

 

[keeter57]

Thanks guys,Ill check it out as you explained