This is a 1996 4.6L with two coil packs. On my car, two plugs coming from the drivers side coil pack are getting spark and the other two are not. I would think that if a coil pack were to fail that all four plugs on that coil would not get spark. So... I tried swapping the coil packs from left to right and I still got the same results, telling me it's most likely not a coil pack.

As part of this excursion I have replaced both the wires and spark plugs, cleaned the connections to coils and still have the same results. I am stumped here and I am thinking that it may be the harness or possibly the computer. ??? (hopefully not)

My main reason for posting is to see if anyone else has ran across these symptoms and can help me to not replace any more parts than I have to.

THANK YOU IN ADVANCE for your help.

 

Are you sure they aren't getting spark and it's not a fuel problem?

I believe your ignition is a waste spark, so two or even all four towers fire at the same time. If it's just half of the pack, then you may have a bad connection to the pack or a bad coil driver.

 

Thank you for your response. I am positive that it's a spark issue. The two that aren't getting spark from the coil pack I believe are cylinders 8 and 3 (don't quote me on that) The connection at the pack is good but I have no idea where to check further up the harness.

So what is a coil driver? Thanks again.

 

So I just read up on this ignition and it is a EDIS8 waste spark type. I gather that the dead holes are most likely 8&5 since they are the corresponding plugs. Now to figure out why those two are down.

 

If you have swapped coils with no change, replace the wires and spark plugs, then it is in the harness or PCM. I don't know for sure on your coil, but most coils have a constant hot, and a trigger which is hot until it is supposed to trigger and it goes to ground. I would imagine that you have a 3 or 4 wire harness going into the coils and that two of those are triggers, so I would start with checking the others for 12v. Hopefully all of them have 12v or atleast all but one.

 

Thanks for your help. I'm learning alot today. I found this pic/diagram.
What is labeled as the (EDIS) Module at the bottom... is that what you are recommending I replace? Thanks again.

 

And also, do you know where that box is located?

 

well, I guess you can disregard the previous post. I found this in a manual...

<i>On 1996 vehicles, there is no longer a stand-alone Ignition Control Module (ICM). The ICM has been integrated into the PCM. The Profile Ignition Pickup (PIP), Spark Output (SPOUT), Ignition Ground (IGN GND), and Ignition Diagnostic Monitor (IDM) have also been enclosed in the PCM. </i>

Looks like there is no replacing seperate parts, gotta replace the whole PCM :-(

 

Are you sure you have a 96 F150 with a 4.6? That isn't even possible according to the service manual.... Check your 8th digit in your VIN.

N=5.0
H=5.8
G=7.5

Now if you're working on something other than an F150.... that would be nice to know.

Steve

 

If I'm not mistaken I don't think ford even made a F-150 that year because of the transition from old body style to new

 

No, there were plenty of 96s made while the plants were transitioning to the 97 model. Both the MY 96 and MY 97 versions were being produced at the same time at different factories until Ford could get all four plants switched over.

I'd suspect he actually has a MY 97 produced in 96. The 10th digit of the VIN and the emissions certificate will tell what MY it is and the decal on the doorframe will tell when it was produced.

In any event, the ignition control functions are integrated into the PCM for all 4.6L F-series applications.

Steve

 

Before you get too heads up into replacing the ECM, find a manual or test procedure for making sure the coil is receiving voltage and trigger.

 

Any idea of where I can get the specs for testing the 3 input wires? I am getting a positive from all 3 when plugged in. I believe the triggers are teh two outer prongs. When I test the prong on the good side I get voltage and the engine stumbles a little bit. When I test the prong for the two dead cylinders I get voltage but no change in how the engine runs. Also, I know I shouldn't have done this but I crossed the wires so that the prongs were reversed and sure enough, the two dead cylinders fired.
Kinda confused about both prongs getting voltage tho.. I'm only using a test light.

 

Verify what you're even working on. There are differences in the systems between years (see previous discussions...)

 

He said 96 car, So I'm thinking TownCar or Crown Vic.