Coil Pack bad?!?

[coleman]

How can I test my coil packs to see if any of them are truly bad?

My idle has been a little rough. Stalling when cold. Low & mid-range misses.
While I was in Austin, SVTADVISOR mentioned that I should look into a bad coil pack...
I was thinking fuel pressure, pumps, spark plugs, injectors, but coil packs seemed equally plausible.
Anyway, I got home this afternoon & swapped coil packs with a friend's Mach1 ... the ride actually improved.
So, I'm thinking some of my coil packs are bad.

Second question is, can I get them replaced under warranty?
How expensive are they?

 

[BlackGT]

had similar problem but for me it was my Midrange power was terrible it feel like a huge hesitation come to find out my #8 Coil was out, so i replaced it and it ran beautifully!

 

[broke7]

Mine had a similar problem, intermittent hard miss like a cylinder was down, so I ran the appropriate compression and leakdown checks and all was good, changed plugs, still did it.

I was about to take it in, and it quit doing it. I would check your main wiring harness up by the passenger side firewall and see if anything is pulled out of the socket.

Could be just a bad pack, they are spendy from what I have heard.

 

[Jimmysidecarr]

If there is any oil in the plug well it can make the coil boot fail.
Yes a new coil does come with a new boot... but like Broke said.... they are pricey...
Isolate the miss(switching coils from cyl to cyl works)
Check every coil boot for oil...
If there is oil... replace the valve cover gaskets and plug tube grommets...
Sometimes the electronic part of the coil fails.... then you will need a new coil.
Plug boots, v/c gaskets, and plug tube grommets are fairly cheap...
High boost cars have higher base pressures(more blowby), than stockers ...
So a little premptive caution is not a bad idea....
Connections can also be an issue .... even more so if there has been .... tear downs
Good luck I hoping its one of the cheaper, easier fixes.
Jimmy
PS:If you need part#s let me know.

 

[coleman]

Pricey? I was expecting maybe 30 each.

No, I didn't see any oil on my coil boots...

Does no one know how to simply test a coil pack?

 

[SVTADVISOR]

Sounds like you already did when you were swapping with your buddy's car. You should have no problem getting them replaced under warranty since it's a known issue and it has nothing to do with your mods. If you get any flack bring it to me and i'll get them fixed. We did them for Racerat already.

 

[coleman]

Lance/SVTADVISOR, but I'd like to verify that one is bad.
I need to get this coil packs back to my friend ASAP & I'd hate to have to put some very suspect ones back in to take it to a possibly mod-hostile dealership for an earfull of ... gripe/moan/nag session, etc...

An if one went bad, what's the likelihood that another may go bad since they are all (most likely) out of the same (possibly bad) batch?!? ... I'm sure they'd only replace the known bad one, right?

Can you send me the TSB information...

 

[Dana]

If you find out how to test them individually, please let me know. We are trying to isolate a problem on a friend's car and we thought it may be a bad coil.
We pulled each one and ohm'd it out. They were all the same, except we don't know what the specs are and if that is a valid test.

Suggestions?

Thanks,
Dana

 

[Hicompression]

Originally posted by coleman
Can I get them replaced under warranty?

You still have a warranty!?

 

[racerat]

Re: Re: Coil Pack bad?!?

Originally posted by Hicompression
You still have a warranty!?

Originally posted by SVTADVISOR
We did them for Racerat already.

There are dealerships who don't freak out and blame everything on mods. :beer:

 

[Boosted 03]

Ohm out the coil pack. Isolate the coil pack from the circuit and check the total resistance of the coil pack. Find out the ohm spec of the coil. If the resistance reading you are getting from your coil is out of spec (higher than spec) than you need to replace the coil. The only bad thing is that it could be a heat related failure which means that the windings in the coil could alter their resistance once the temp. is raised throwing them out of spec. Check your connections and be sure your plug is in good shape. The spec for the packs resistance will be measured cold. Good luck. Don't rule out a glitch with the TPS or the crankshaft positioning sensor. :thumbsup:

 

[coleman]

I'm taking my car to Doug Stanley Ford tomorrow so that can help determine the root cause. Someone else mentioned IAC as a possibility as well...

My car is running better, but I reset the computer which may be why it seems better.

 

[racerat]

Coleman, when mine was bad I was getting misfire codes. The check engine light only did the flashing thing once, but a soft code was thrown multiple times.

 

[Bingo13]

Coleman,

What chip/tune are you running? If it is SCT I have the equipment to diagnose most of the issues now. How do your plugs look? I have seen the number 7 and 8 coil packs go out on a consistent basis, just like everything else that is wrong in that area of the engine. ;-)

 

[coleman]

racerat, I'm not seeing any codes with the SCT programmer... no CEL.

Bingo13, custom tune from when this engine was originally tuned back in April ... I haven't used my SCT Racer package yet. Not until I install this MAF-x-tender. But I won't do that until I resolve this issue...

Plugs didn't look out of the ordinary... I already swapped the plugs to see if that was the problem. New plugs didn't help.

New coil packs seemed to improve things, but I had reset the computer which is messing up any diagnosis that I can do

 

[DR. WU 2000]

Would a faulty coil pack cause you to have lower #'s on the dyno?
My question is I recently had a Autometer tach installed and the shop who did the install had some trouble with the wiring working on the normal wire bundle that runs inside the engine compartment. So the genius tried to splice into one of the coil packs and proceeded to shred up the wire while doing it. He eventually needed to put in 2 splices and add wire to make the connection. Ever since then I felt the car had lost something in the midrange. I had I dynoed and I am making MORE power than before this mess. Maybe it's just me but it still feels like it's not as strong as before. I am wondering if the coil pack mess may be causing the problem?:shrug: I did a diagnostic check with my Predator and found no codes. Maybe I am getting used to the power and it just feels slower. :cryying:

 

[Dana]

Originally posted by Boosted 03
Ohm out the coil pack. Isolate the coil pack from the circuit and check the total resistance of the coil pack. Find out the ohm spec of the coil. If the resistance reading you are getting from your coil is out of spec (higher than spec) than you need to replace the coil. The only bad thing is that it could be a heat related failure which means that the windings in the coil could alter their resistance once the temp. is raised throwing them out of spec. Check your connections and be sure your plug is in good shape. The spec for the packs resistance will be measured cold. Good luck. Don't rule out a glitch with the TPS or the crankshaft positioning sensor. :thumbsup:

Boosted,
We ohm'd them out hot. All were identical.
As they cooled, the numbers dropped slightly.
I find it unlikely that they are all bad.
I don't know what the specs are supposed to be though.

Dana

 

[04silversnake]

I had the same problem not in my cobra, but in a 2000 gt, same symtom. Yes its is covered under warranty.

 

[Bingo13]

Originally posted by coleman
racerat, I'm not seeing any codes with the SCT programmer... no CEL.

Bingo13, custom tune from when this engine was originally tuned back in April ... I haven't used my SCT Racer package yet. Not until I install this MAF-x-tender. But I won't do that until I resolve this issue...

Plugs didn't look out of the ordinary... I already swapped the plugs to see if that was the problem. New plugs didn't help.

New coil packs seemed to improve things, but I had reset the computer which is messing up any diagnosis that I can do

I had the #7 coil pack go bad on me but the plug was fouled so it was easy to figure out without changing out each coil pack. I had the stall and rough idle come back two weeks ago when the temps dropped in the morning.
I reset the computer, did not have any code issues before or after, and installed the new SCT Super MAF and changed the tune slightly, the car idles like a kitten now. I still have some dyno work to do for the new MAF but it seems to be the best $250 I have spent on the car so far as the top end is totally different now and gas mileage is up from 14 to 18.

 

[coleman]

update!!!

I swung by Doug Stanley Ford this morning and they were able to identify my issue in short order and even went the extra mile & helped me out with a few other items.

As it turns out, my DPFE sensor tubes were reversed. That accounted for most of my problems. One of them even popped off & they put it back on there. I had used the wrong type of tubing when I last had the KB off. The fuel line that I had used had become hard over time & popped right off.

Ronnie Greer (Service Advisor) and Ruben (Smart Tech) :beer: helped me out immensely! James also did a great job flushing my radiator and replacing it with distilled water & water wetter :thumbsup:

Ruben was not able to pickup on any misses (bar one on #2).
The car is running much smoother now...

Now my CATs are coming apart ... most of one is in my muffler ... rattle, rattle