2.3L ('83-'97) no spark from front coil

[Rick D.]

i'm working on a 96 ranger 2.3 Liter with a 5 speed manual. i don't have any spark coming from the front coil, and i have done a lot of work to it in the last 2 weeks, i have replaced the timing belt the air idle solenoid, throttle control sensor, both coils, PCM has been changed twice. new plugs and wires, new gaskets on the intake manifold ,water pump and thermostat. i checked the the wire connectors on the coils and the front coil has 12v power to the center of the plug but the outer wire is not pulsing, i have been taking all the wire loom off looking for a short or broken wire but i have found nothing so far. Please help or anything i should be checking next would be a great help. thanks CEL is on and its throwing the codes P0351,P0352

 

[RonD]

Welcome to TRS

I assume you tested rear coil and it's 2 ground wires are pulsing with your test method when unplugged from coil pack

In 1996 both coil packs should get the same ground pulses(1994 and earlier will not)

So you should be able to start and drive the vehicle with either coil pack unplugged
Two spark plugs in each cylinder are used to increase performance, they are not "needed", the 2.3l ran fine for 14 years with just 4 spark plugs

You can use an ohm meter to test coil pack itself, .8-1.5ohms between 12v and ground pins is expected

The system is pretty straight forward
The 4 coil ground wires run back to the computer, inside computer are 4 transistors, one for each wire, these pulse the ground for each coil in the 2 coil packs like points did in a distributor
So if there is no grounding on one coil pack then those 2 wires are bad or transistors in computer are bad

The coil packs ground wires are all "Tan" with a different colored stripe
Tan/white goes to pin 26 on computer
Tan/orange goes to pin 52

Tan/blue goes to pin 78
Tan/green goes to pin 104

Pin layout here: https://www.grandmarq.net/oldfuelinjection/images/eec05.gif

Pin 104 should ID the others for you

Pull off computer connector and OHM the effected wires to see if they are broken, if they are OK then computer is the issue

 

[Rick D.]

Welcome to TRS

I assume you tested rear coil and it's 2 ground wires are pulsing with your test method when unplugged from coil pack

In 1996 both coil packs should get the same ground pulses(1994 and earlier will not)

So you should be able to start and drive the vehicle with either coil pack unplugged
Two spark plugs in each cylinder are used to increase performance, they are not "needed", the 2.3l ran fine for 14 years with just 4 spark plugs

You can use an ohm meter to test coil pack itself, .8-1.5ohms between 12v and ground pins is expected

The system is pretty straight forward
The 4 coil ground wires run back to the computer, inside computer are 4 transistors, one for each wire, these pulse the ground for each coil in the 2 coil packs like points did in a distributor
So if there is no grounding on one coil pack then those 2 wires are bad or transistors in computer are bad

The coil packs ground wires are all "Tan" with a different colored stripe
Tan/white goes to pin 26 on computer
Tan/orange goes to pin 52

Tan/blue goes to pin 78
Tan/green goes to pin 104

Pin layout here: https://www.grandmarq.net/oldfuelinjection/images/eec05.gif

Pin 104 should ID the others for you

Pull off computer connector and OHM the effected wires to see if they are broken, if they are OK then computer is the issue

 

[Rick D.]

Thanks Ron I will test those wires with the ohmmeter and hopefully it’s a wire because I replaced the pcm twice and the CEL back on. Thanks for the information I appreciate it.

 

[RonD]

What codes did you get?

Engine should still be running OK with just one coil pack, it just won't have quite as much power

 

[Rick D.]

P0351/P0352 is the codes that come up, it does run ok but it misses a little when at a traffic light and I’ll be checking the wires with the ohmmeter hopefully tomorrow night .

 

[RonD]

P0351 Ignition Coil A Primary/Secondary Circuit Malfunction
P0352 Ignition Coil B Primary/Secondary Circuit Malfunction

So that means computer is either not seeing 12volts FROM the 2 coils in the pack, so bad coils or wires
Or transistors in the computer are bad

 

[Rick D.]

P0351 Ignition Coil A Primary/Secondary Circuit Malfunction
P0352 Ignition Coil B Primary/Secondary Circuit Malfunction

So that means computer is either not seeing 12volts FROM the 2 coils in the pack, so bad coils or wires
Or transistors in the computer are bad

P0351 Ignition Coil A Primary/Secondary Circuit Malfunction
P0352 Ignition Coil B Primary/Secondary Circuit Malfunction

So that means computer is either not seeing 12volts FROM the 2 coils in the pack, so bad coils or wires
Or transistors in the computer are bad

Hey Ron just wanted to let you know I tested all the wires and no breaks, turns out it was the PCM that’s the 3rd one in the last month the first one I had problems and luckily the took it back and the second one was the problem I just had and of course they wouldn’t take the second one back but the 3 one fixed everything, I just wanted to say thanks for all the advice you gave me because it worked perfectly.

 

[RonD]

Good work

Very rare to have PCM problems and 3 of them...............buy lotto tickets your DUE

And thanks for the follow up post