2 and 6 misfires

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Zpak

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Asking for a friend ;)

So I’m interested in throwing my hat into the Gen 2 arena. Considering purchasing a ‘93. It has almost no miles on the engine post rebuild because it started to run bad soon after the current owner got it back. This all took place in 2018. The car has been in and out of the shop that did the work and to date has still yet to be sorted out. The man isn’t very mechanically inclined, no fault of his own, so troubleshooting has been difficult. I myself have never owned an early gen so I figured I’d pose the question to the pro’s who know the ins and outs of this engine.

This is the story he’s telling me:

About 100-150 miles after getting SHO 1 back, she started to run poorly….LOW rpm idle of 300, hesitancy when accelerating, poor overall acceleration, and some misfiring, so I immediately took the car back to my mechanics at “McWilliams and Walden”
They had a company “Tech Net professional Auto Care” do the diagnostic which stated:
“Inspected and found engine running poor due to misfire on cylinders 2 and 6, found no spark on cylinders 2 and 6, inspected and found ignition coil shorted, replace coil, inspected and found after replacing ignition coil cylinders 2 and 6 misfired at idle only, labscoped coil signals and found ignition module dropping signal at idle, shorted coil damaged ignition module, replace module.
They then removed and replaced ignition coil and they replaced the ignition module. This all occurred on May 9 2018

On May 14 2018 I was notified by Brint @ McW & W that “it needs an ignition coil pack and we are going to replace ignition module”.

So they did, got the far back, and same scenario starting all over again (for the 4th time), exact symptoms, same diagnostic results, same new parts installed, same results. On one of the four times, they said I needed new spark plug wires because (they blamed the new Motorcraft WR-13 wires I provided) as being no good…..I had bought them from SHOSOURCE a few years earlier as “back ups” if I needed them, so I doubt they were bad. They replaced them with some MickeyMouse brand my mechanics supplier ordered that also went bad due to whatever is going on. I think the Motorcraft stock and preferred AGSP doubke platinums are back in it.
I think the new coil pack they installed at first was faulty and that it might still in the car and if so, that could be what is causing the problems. I think they need to replace the coil pack they first put in because I think it’s bad like the original (stock one) was declared bad.
As far as the DIS, I only included that as a possibility in the event my “burst” cable shield is connected to it (DIS). (hard to tell).
Some dates may be off, because this SAME THING has occurred each time they tried to “fix” it, a total of 4 times,?- and counting(?)
They keep replacing the same damaged parts, but aren’t fixing what’s causing them to get damaged?

So there it is. Any direction would be greatly appreciated.
 

rubydist

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I immediately thought "coil pack" when I started reading your post. Then I got to the part where they replaced that and it had almost the same problem. So, I wondered what coil pack did they use? Most of the aftermarket coil packs for these are notoriously bad, often bad right out of the box, so a new coil pack with the same symptoms does not mean that it is something other than the coil pack that is bad. Most of us have resorted to scrounging used Ford coil packs from the jy rather than spending money on aftermarket junk coil packs. So, I would get a Ford Motorcraft coil pack (hopefully a known good one) from somewhere and replace that first. While I was at it, I would look at plugs (at least from 2 and 6) to see that they are not all fouled up. Then I would be spraying water on the plug wires while it runs to make sure there are no shorts in the wires.

If, after that you still have an issue, then I would replace the DIS, again with a Ford Motorcraft part, not aftermarket (hopefully a known good part) and see what that does.

It is also possible that the PCM is bad, but I personally have not seen a bad pcm with this symptom.
 

Zpak

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That’s exactly the knowledge I was hoping for! Now I can give him a good place to start. Thank you.
 

luigisho

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I agree with rubydist. Coilpack was first guess, then DIS, PCM and wiring are also targets.
 

Zpak

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Interesting idea, I’ll relay that info. Would be nice if it was something so simple.

As for an update, he is awaiting a FOMOCO coil pack from SHOsource so we’ll see what happens.

To indulge my internet search laziness could anyone confirm the cylinder positions for the 3.2? Are they…
Firewall 1 2 3
Front 4 5 6
 

rubydist

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no.

coil pack:
5 1
6 2
4 3
front of car
 

Greg Corcoran

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I must need more coffee this morning... there are two different coil pack arrangements above, one from Nick and one from Rubydist? They can't both be right. In Rubydist 2 and 6 fire together so a string of bad coil packs makes sense, in the other they are on different coil packs, mis-routed plug wires might make sense.

I thought Nick's illustration was correct? And if it is misrouted wires, then the car would not have run well for the first 150 miles (unless someone fiddled with it for some unknown reason), it would have this issue from the get go after the rebuild? Also they WOULD have seen spark on 2 & 6, just not at the right time when at TechNet Professional for diagnosis. so this points to weird/unlikely/black swan source like the PCM. What am I missing (he says as he stumbles off to get more coffee)?

PS - Adding to my haze - I was nearly certain Technet Professional is actually a warranty service that many higher end independent shops opt into to cover each other's warranties nationwide, not the name of a particular shop? So when you see TechNet Professional the car is looked at by another member of the network than the original shop... For example if your repair has a lifetime warranty and you move, or you are on a road trip and a covered repair breaks again. Where we take my wife's Mini here in Colorado is a member of TechNet Professional Auto Care. We recently had to take her car to a TechNet Professional member while we were on a road trip out of state.
 
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luigisho

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Look at Kevin's photo last post. This will SHO you the correct cylinder and corresponding coil orientation. Make sure the plug wire runs from the corresponding cylinder and the number on the coil pack. Just in case. But yes, it should misfire from the beginning with incorrect coil to plug routing.
 

zoomlater

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Look at Kevin's photo last post. This will SHO you the correct cylinder and corresponding coil orientation. Make sure the plug wire runs from the corresponding cylinder and the number on the coil pack. Just in case. But yes, it should misfire from the beginning with incorrect coil to plug routing.
That's pretty clear
 

Zpak

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Just for a little update here. He did have the coil pack changed with a new FOMOCO unit. Tried to fire it up and nothing. The mechanic that came to dudes house to change the coil asked, does it have gas? Gauge read 1/2 tank but come to find out…bone dry. So sending unit is shot. They added fuel and still nothing. So, apparently the pump is also toast.

I’m now thinking it makes sense the dying pump could have been his low idle and sluggish acceleration issue this whole time. However, still doesn’t explain the misfires. Which, may well have been addressed with the new coil pack but is unable to test as now it also needs a fuel pump and sending unit.

Shaking fist at the sky, SHO’s!!!! At this point he’s given up putting money in the car and wants to sell As Is. And I’m thinking, costly rabbit hole. Super nice car though.

IMG 5202
 

zoomlater

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nice car, did they try getting it to run by spraying starting fluid
 

SM105K

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Nice car, I almost had a heartache when I read the title....lol. A weak fuel pump would cause miss fires as well.
 

SM105K

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Oh I am sure, then I read it was in the GEN 2. That makes sense why you asked me about them on our test drive.
 
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