Modded Mustang Forums banner

1 - 19 of 19 Posts

·
Registered
Joined
·
19 Posts
Discussion Starter #1
I got a set of used screamin demon coil packs the other day. The guy said they had no issues when he removed them. Now my car misfires when giving it some throttle. It idles fine and if I drive it normal I don't notice any problems. It's only when I start to give it maybe 3/4 throttle or so.

Wasn't sure if the coils would be affected by timing and if I should turn it down or what. When I put them on I was sure to make sure each plug wire was snapped on tight.

Any ideas?
 

·
Head Unicorn
Joined
·
5,085 Posts
He most likely rid himself of the worthless aftermarket coils because they're ****. They may have produced more output when new... but they have undoubtedly failed and he raped you by selling them to you (i'm assuming you've installed everything correctly). If by chance you have made an error in installation that you are able to fix and the misfire disappears..... don't worry, it'll be back soon. I hate to be the bearer of bad news but take those pieces of **** out and plant them in the garden. If you want a high quality replacement that will provide more spark than you could ever use go buy either Ford or Motorcraft. All other will fail, it doesn't matter what sticker is slapped on to the side of them or what color the plastic is molded in. Ford and Motorcraft.
 

·
Registered
Joined
·
2,936 Posts
I got a set of used screamin demon coil packs the other day. The guy said they had no issues when he removed them. Now my car misfires when giving it some throttle. It idles fine and if I drive it normal I don't notice any problems. It's only when I start to give it maybe 3/4 throttle or so.

Wasn't sure if the coils would be affected by timing and if I should turn it down or what. When I put them on I was sure to make sure each plug wire was snapped on tight.

Any ideas?
Is is not uncommon for old plug wires to be damaged when removing/reinstalling them. How old are they, how many miles on them? Also how many miles on the plugs?
 

·
Registered
Joined
·
19 Posts
Discussion Starter #5
Plugs and wires are around a year old. It's my dd so it has dd miles from a years worth of driving. I'll check the plug wire ends but I don't think it's them. I can always put the old ones back on to check.
 

·
Head Unicorn
Joined
·
5,085 Posts
About a years worth of use you say? Kind of ironic..... most aftermarket COPs tend to fail around a year old.
 

·
Registered
Joined
·
2,936 Posts
Plugs and wires are around a year old. It's my dd so it has dd miles from a years worth of driving. I'll check the plug wire ends but I don't think it's them. I can always put the old ones back on to check.
It does not have to be the "ends", they can breakdown internally as well...
 

·
Registered
Joined
·
19 Posts
Discussion Starter #8
Changed back to my old coil packs and no more misfire. Looks like one of the coils is bad. I think I'll just convert to cop this weekend since I have all 8 that came with the engine lol
 

·
Registered
Joined
·
2,936 Posts
Changed back to my old coil packs and no more misfire. Looks like one of the coils is bad. I think I'll just convert to cop this weekend since I have all 8 that came with the engine lol
Do you have the wiring harness and PCM also?
 

·
Registered
Joined
·
19 Posts
Discussion Starter #11
Yes, but from what I remember I don't necessarily need the 04 computer, and I do have the harness but was going to take what I need off of the 04 harness for cop, and wire it to my current harness. Now debating if the work involved is worth a cleaner looking engine bay.
 

·
Head Unicorn
Joined
·
5,085 Posts
I feel like I'm missing something here. I feel like Cliffy knows something I don't know. It got me curious enough to google "screamin demon" and what I found was the early SN-95 Modular dual coil packs instead of COPs. There's nothing posted about vehicle info in your sig or avi......... yet you referred to using the 04 harness. What Frankenstein are you working with here?
 

·
Registered
Joined
·
19 Posts
Discussion Starter #14
Sorry. 96 body. 04 motor with my 96 harness and coil packs. I still have everything else from the 04 that i would need that came with the engine. Sorry for the confusion.
 

·
Head Unicorn
Joined
·
5,085 Posts
He says he has the coil packs, but has the wiring harness and PCM for an 04 so he can convert to COPS.
That's why I was asking..... the parts he was speaking of were early style, not COP.... I was trying to figure out why he had the early style, now that I see he's in the early SN95 I understand why.
 

·
Registered
Joined
·
2,936 Posts
Sorry. 96 body. 04 motor with my 96 harness and coil packs. I still have everything else from the 04 that i would need that came with the engine. Sorry for the confusion.
You will need to use the '04 PCM, the earlier one has no provision for firing eight coils (COPs), only the four used by the EDIS.

In theory I suppose you could wire the COPs in a wasted spark configuration, however I do not know that the older PCM driver MOSFETs could handle the load...
 

·
Registered
Joined
·
19 Posts
Discussion Starter #17
From what I remember, it still fires in a wasted spark configuration unless I change the computer. I could be wrong, it's been a while since I looked into it. I'll try the ol' google search later to see of that's correct. I might not mess with it. It would look nice though.
 

·
Registered
Joined
·
2,936 Posts
The EECV systems using COPs only fire in wasted spark mode at start-up, just until the #1 compression stroke TDC can be located based on the cam position sensor signal.

It also does a triple-strike firing at idle and up to 1200 rpm or so to assist in starting and reduce emissions--it looks like this on a 'scope:



Three firings at 1.4 ms intervals...
 

·
Registered
Joined
·
250 Posts
i have a 96 GT. i have COP conversion with forced induction. i make over 500hp on a t-trim.
 
1 - 19 of 19 Posts
Top