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Wildman5977
Dodge Dakota
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6/30/2005
01:32:27
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 Subject: 4.7 V8 Ignition coils
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I recently did a plug change and oil change on my 4.7 V8 CC 5 Speed Manual, 37500 miles.
I found one coil was bad from primary to secondary, the chiltons book I have says the primary should measure 5-500 Ohms and primary to secondary should measure 6-9K Ohms, I used a 1/4 inch extension for the primary to secondary measurements, I found a bad coil on #7 cylinder that read an open from primary to secondary.
I did not have any fault codes.
I did have other symtoms.
My average milage was 18+MPG
BTW- Dodge dealership said they don't go bad.
I have the platinum extended warrenty and they are a warrenty replacement item but for the dealer to inspect it was a $100 service charge.
NAPA sells replacements for $30-36 each, dealer charges $42
I will be checking these once a year now.
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dan
Dodge Dakota
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7/05/2005
22:35:16
| RE: 4.7 V8 Ignition coils
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what were the symptoms you had to make you check the coils? did you check on a scope or was it a drivability issue?
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Rob C
Dodge Dakota
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7/07/2005
01:15:48
|  RE: 4.7 V8 Ignition coils
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Rockauto.com has them for $21.99 each plus if I can find it, I'll post a discount code for 5% off any purchase. These guys ship fast and them don't charge an arm and a leg for shipping either.
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Rob C
Dodge Dakota
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7/10/2005
14:24:12
| RE: 4.7 V8 Ignition coils
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Discount code: 242177199389
Sorry it took so long. Code expires August 16th.
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rgathright
Dodge Dakota
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7/11/2005
15:17:12
| RE: 4.7 V8 Ignition coils
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Here is a good product many forum members are looking for feedback on. Try it??
http://www.ignitionsolutions.com/products.asp
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Wildman5977
Dodge Dakota
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7/14/2005
05:57:17
| RE: 4.7 V8 Ignition coils
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Primarily it was just a tune up, I was not going to measure the coils, just change the plugs, then I saw the measurement info.
As for symptoms, it seemed a little slower than normal and a bit more hesitant from a stop, and the fuel milage had degraded to 16-17mpg
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Gary F
Dodge Dakota
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7/17/2005
12:45:08
| RE: 4.7 V8 Ignition coils
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rgathright: Personally I'm a little sceptical of any real improvements over the factory setup without seeing any real data. There are too many products out that make promises and don't deliver.
Wildman5977: Be careful of those Chiltons books. I've seen plenty of mistakes in them over the years. Anyway, my shop manual says that the Primary Coil Resistance is 0.6 - 0.9 Ohms. My thinking is that there is nothing wrong with the coil. There are check engine light codes for coil problems (P0351 through P0358) along with cylinder misfire codes. If you don't have a check engine light on and it drives OK, I wouldn't worry about it.
Gary F
01 Dakota Sport reg cab 4x2, 4.7L, 5 spd, 3.92LS
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Rob C
Dodge Dakota
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7/18/2005
05:05:17
| RE: 4.7 V8 Ignition coils
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Wildman5977, there shouldn't be any continuity between primary and secondary windings, what were you reading on all the other coils?
My factory manual says: primary resistance .6-.9 ohms, secondary resistance 6K - 9K ohms, nothing about primary to secondary resistance. A coil is basically a step up transformer, in this case, a 10,000 X step up. Therefore, you are suppose to be getting approximately 120KV at each sparkplug.
I guess I was focused in on coil price and not the data you were providing.
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Gaston
Dodge Dakota
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7/18/2005
14:15:40
| RE: 4.7 V8 Ignition coils
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Typically, one end of the primary and secondary windings is tied to ground. It's usually done in the coil assembly, since electrically it's the same point. That way the coil only needs three terminals: B+, ground, and output to spark plug.
If his coil shows no continuity between primary and secondary where there should be, and the coil is still firing the plug, then the secondary is probably arcing to the primary for a return path to ground, and will eventually fail.
A schematic of the coil should show this arrangement.
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Rob C
Dodge Dakota
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7/18/2005
21:11:13
| RE: 4.7 V8 Ignition coils
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Good point, unfortunately the factory manual doesn't get that detailed.
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Cynic
Dodge Dakota
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7/19/2005
00:54:05
| RE: 4.7 V8 Ignition coils
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That's because they don't want the technician to know how the coil works, only how to use a DRB III Scantool to see if the computer thinks it works.
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Wildman5977
Dodge Dakota
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7/22/2005
00:32:55
| RE: 4.7 V8 Ignition coils
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When I was checking the coils, most measured correctly beside the one that did not, I had 7.0-7.5K ohm measurement from the primary to secondary, except for the one coil which I have replaced.
BTW- I have worked on cars since about 1972, I have an associates equivelent in electronics, I have worked in maintenance for 30+ yrs.
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2die4
Dodge Dakota
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4/27/2006
00:38:28
|  RE: 4.7 V8 Ignition coils
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If anyone is there? I have a V6 1997 Dakota that is ill! Missing/Cutting out complete at 60 mph/some backfiring/sounds like #5 fuel injector may be clogging up (B-12 helped). A friend ran a code "igniton coil A Primary to Secondary Circut Malfunction". I saw only one ignition coil. I replaced it, no help. My owners manual is very NOT DETAILED!!! The Code book listed codes for coils A-L? where are these, why doesn't my owner manual talk about them? I called a dealership mechanic 4 help and got'put in my place'. I wish I could take it in, but no funds at this time, feel that? Any and all assist is invited and truly appreciated. Thanks, Diane (2die4)(excuse any mis-spelled words)
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Adam
Dodge Dakota
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4/28/2006
23:55:23
| RE: 4.7 V8 Ignition coils
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The v6's only have one ignition coil. The 4.7's have a seperate coil for each sparkplug. If you think it's a spark issue try checking your wires, distibuter cap and plugs. If you replaced your coil already dont worry about it unless your problem leads to your coil going bad.
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Paul Symmonds
Dodge Dakota
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6/17/2013
15:19:52
| RE: 4.7 V8 Ignition coils
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Message:
I just replaced my 4.7 engine because my mechanic told me something was wrong with two of the cylinders (#5 and #6). The coils in both the cylinders were melted so badly they looked like nuclear waste. (I'd just replaced all of them two months before, and only one was bad at that time.) So the new motor fires right up, but within two minutes begins to runs roughly, just like it did before I replaced the engine. I can't find any shorts and I replaced O2 sensor wires that had been damaged by heat. WTF? Has my computer gone bad?
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Corn
Dodge Dakota
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6/27/2013
19:13:14
| RE: 4.7 V8 Ignition coils
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Message:
Yes.
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