This is topic Ever had an ignition coil go bad? in forum Tech Talk at Northern California Ford Owners  .


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Posted by st5150 (Member # 51) on :
 
Have any of you guys ever had an ignition coil go bad? If so, what were the symptoms? I'm trying to trace a slight slow mis above 3,000 RPM and two-thirds or more throttle.
 
Posted by FasterDamnit (Member # 442) on :
 
Only one, An Accel Super coil. I still have my stock coil if you need it. No charge. You did replace ALL your wires and plugs, right?
[Razz]

JL
 
Posted by st5150 (Member # 51) on :
 
Yes, in the past month I've replaced

plugs
wires
cap/rotor
air filter
alternator
battery
ignition switch
tried a new MAF electronics
cleaned 10 pin connectors
cleaned EEC's connectors

If its the plugs, I would have had to cracked the ceramic while installing it, but I highly doubt that happened.

The mis is a slight "fart" through the exhaust... probably very hard for a passenger in the car to notice. I can tell it effects power and makes the engine slower revving up top. It "farts" about every other second while revving through the powerband. I don't have time left on my vacation to replace the plugs or do a compression check. I have a new fuel filter here, but I doubt its my problem so I don't think I'll install it.

On the flip side, as a result of this tuneup, my car idles and drives like a Lincoln under light low and/or below 3,000ish RPM.
 
Posted by FasterDamnit (Member # 442) on :
 
Well,
If it idles that smoothly maybe it is fuel delivary at higher rpms. The fuel filter is pretty easy to change...
 
Posted by st5150 (Member # 51) on :
 
Yeah, I'm sick so even the thought of smelling raw gasoline makes me want to puke. Usually I've noticed fuel delivery problems "pop" through the intake and ignition problems "pop" through the exhaust. I've had an extremely clogged fuel filter&pump before and after 3,000 RPM the motor would rev extremely slow due to the lack of fuel, yet it would still rev smooth. In the 99,000+ miles I've driven my 5.O, I've installed fuel pumps 4, maybe 5 times. The only item I've installed more often is a Pep Boys oil pressure sending unit...easily half a dozen of those thanks to warrenty.
 
Posted by ONELOWSPLITBUMPR (Member # 2067) on :
 
i still think it is the fuel filter, but that is my opinion, how about dirty o2 sensor or some clogged exhaust?
 
Posted by st5150 (Member # 51) on :
 
Okay, you guys talked me into it, I'm installing the new fuel filter tomorrow, but I doubt its my problem.

As for O2 sensors... it does this at wide open throttle where the O2 sensors aren't read by the computer so they can't be at fault.

As for clogged exhaust... its free-flowing and clog-free [burnout]

If I blew a header gasket, I would be able to hear it no matter what right?

[ November 30, 2002, 07:39 PM: Message edited by: st5150 ]
 
Posted by jmcclesk (Member # 1355) on :
 
Is there any way you can check fuel pressure while driving. To see if you are losing pressure under high load???. I have seen it before. As far as ford coils going at high miles YES.

[ November 30, 2002, 07:50 PM: Message edited by: jmcclesk ]
 
Posted by st5150 (Member # 51) on :
 
Well its not the fuel filter [Frown] I'm running a different brand rotor than I am the cap so I'm about to go get a matching brand rotor...but I doubt this is my problem. $17 for an AutoZone coil... I'm about to go get one and return it if it doesn't fix my problem.
 
Posted by st5150 (Member # 51) on :
 
Well that completes my AutoZone ignition setup.... got the rotor and coil. At first I was happy my problem was fixed... then I drove it some more and bumped up the timing to 12 degrees and filled her up with 91 octane. The problem is still there, but not nearly as bad. If I have time tomorrow or the day after, I'll take out my new plugs and check their resistances and look for cracks in the ceramic. If the plugs turn out fine... its time to stick in a new distributor and TFI. I should probably do a compression check when the plugs are out as well.
 
Posted by Cobra5.0Jeep (Member # 1482) on :
 
my coil glowed red thats how i knew it was bad.
 
Posted by 91sleeper (Member # 779) on :
 
Hey I am still having the exact same problem with my car Sawson and havent been able to find the problem.

I am throwing new plugs in my car by the end of this week. I doubt that the cap/rotor was your problem as well as the coil, I say that because I have an aftermarket blaster coil that I have on my car and its brand new, a couple thousand miles are on it and my car acts the same as yours, so I think it is something else.

I might try to throw my stock one on there to see if maybe the MSD coil went out well see. First I need to get my car started again, have to replace the starter.

[ December 23, 2002, 08:07 AM: Message edited by: 91sleeper ]
 
Posted by st5150 (Member # 51) on :
 
UPDATE:

Took out the plugs and did a compression check. Motor was ice cold. I didn't feel like messing around with a hot engine this afternoon. Numbers in the order tested:

Cyl#5: 150psi
Cyl#6: 149psi
Cyl#3: 143psi (there was some bleed down, I didn't feel like tightening the connector)
Cyl#1: 145psi
Cyl#4: 155psi
Cyl#2: 144psi
Cyl#8: 155psi
Cyl#7: 149psi

Great compression numbers for a 230,000+ mile motor... but I'm sure the leak down numbers tell a different story. I compared these numbers to ones from 30,000 miles ago and their identical for the most part.

I pulled all the plugs... no cracks and the internal resistances of all of them were ~4K Ohms. I stuck everything back together and took her for a spin... no problem what so ever. Lets hope it stays that way. It was pulling very hard throughout the power band. In fact, if I had to guess... I'd say it's pulling harder from 60 to 100 mph than Pinole's finest teal '93 Cobra [Big Grin] [worship] [burnout] [dance]
 
Posted by CobramanPhil (Member # 2170) on :
 
Hey st5150,

I ran into a situation like this with a couple of my buddies cars. It was never a coil thing (bad coil wire to the distributer and a loose connection at the coil), but never a coil itself. One thing you might to think about (your probably figured this out already), but there are some aftermarket caps/rotors which are simply not good. The variances in the molds they manufacture these parts are slack. Since there seems to be some improvement with the new autozone rotor/cap..try a motorcraft one to see if it even helps more (plus you will have extra the autozone spare if you really have to use it).

Other than that check the distributer....this will cost the most...so hopefully it is not that.
 
Posted by Tri-Bar (Member # 2191) on :
 
I have had a coil's go bad, It can happen. After you check all the other things with a meter, you check the coil.
 
Posted by 91sleeper (Member # 779) on :
 
Finally! I got my car running again and after I did that I installed all of new plugs. Guess what, no more backfiring/miss firing in the xhaust! I'm so happy my car has never felt better. [patriot] I'm so happy.
 




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