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I have a 2004 grand caravan with 3.8l v6 105000 miles. I took it to the shop for a check engine light and missfire. They replaced the coil pack and reprogramed the computer. When i went to pick up the miss was still there. Sure enough after 3 starts the check engine light came back on. Now they are trying to tell me that the bad coil pack made the injector go bad. To me this dosent sound possible. Looking for opinions.
 

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Whether or not a spark plug is firing has no effect on the injector. Furthermore it is easy to test for yourself if an injector is bad. Get a Mechanic's Stethoscope for under $10 from Harbor freight tool, Northern Tool or Ebay. Place your stethoscope on the lower metal part of the injector. At idle listen for a steady click click click as even as a clock. You should be able to get in a position to get your stethoscope on all injectors, listen to all of them, they should all sound the same. When an injector goes bad it will stop or intermittently click.

You can listen to them a little over idle, but you will loose track of the clicks fairly quickly as the RPM increases.

BTW, i would never go back to that shop again.
 

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I would love to hear their detailed explanation of how that could happen. I'll second the "stay away" statement.

wally - What program are you using to superimpose your "test here" graphic on the photo?
 

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“What program are you using to superimpose your "test here" graphic on the photo?”

FastStone editor, it is a program similar to Microsoft Paint. I like it because it loads in at startup. You just hit the print screen button on your keyboard and it pops up ready to edit the picture on your screen. Or you can load the picture in with the file menu. It is a little easer to use than Paint, at least the one i have in XP.
 

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“What program are you using to superimpose your "test here" graphic on the photo?”

FastStone editor, it is a program similar to Microsoft Paint. I like it because it loads in at startup. You just hit the print screen button on your keyboard and it pops up ready to edit the picture on your screen. Or you can load the picture in with the file menu. It is a little easer to use than Paint, at least the one i have in XP.
Thanks wally. Sounds like the way to go. I'll check it out.
 

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I'll second the "stay away" statement.
Thankyou for the replies.
I would love to take it some where else but the service contract states i must take it to the selling dealer if with in 60 miles.
The van is still there now. I have told the service writer (who has only been thee for less than a week!) that they will be fixing it and i will not be paying the bill. He has yet to get back to me.
 

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They replaced the coil. Did they check the plug wires, as well as the spark plugs? Both of these would also give the misfire.

A hose held to your ear can be a substitute for a stethoscope.
 

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I would love to hear their detailed explanation of how that could happen. I'll second the "stay away" statement.

wally - What program are you using to superimpose your "test here" graphic on the photo?
Here was the story given to me. Apparently according to him electronic fuel injection means that the coil pack gives power to the injectors. When the coil pack went bad it was not giving power to the injector and now the injector leaks down causing the miss. Now that i have had my good laugh for the day its time to drive to the dealership and talk to the service manager in person.
 

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“Here was the story given to me. Apparently according to him electronic fuel injection means that the coil pack gives power to the injectors. When the coil pack went bad it was not giving power to the injector and now the injector leaks down causing the miss.”

That is nonsense the man is an idiot or a liar. The coil pack powers nothing. The PCM fires the coil and injectors and the ASD relay powers the coil pack and the injectors. (green/orange wire).
 

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“Here was the story given to me. Apparently according to him electronic fuel injection means that the coil pack gives power to the injectors. When the coil pack went bad it was not giving power to the injector and now the injector leaks down causing the miss.”

That is nonsense the man is an idiot or a liar. The coil pack powers nothing. The PCM fires the coil and injectors and the ASD relay powers the coil pack and the injectors. (green/orange wire).
Thanks for the details wally. I was sure it worked the way you described but did not no all the details. Basically power for coil pack and injectors comes from ASD relay. Then the PCM gives the ground to fire coils and injectors? Again thank you for you help. i believe they screwed up on the first diagnosis / repair and are now trying to take me for a ride.
 

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“Thanks for the details wally. I was sure it worked the way you described but did not no all the details. Basically power for coil pack and injectors comes from ASD relay. Then the PCM gives the ground to fire coils and injectors? Again thank you for you help. i believe they screwed up on the first diagnosis / repair and are now trying to take me for a ride.”

Yes, that is correct. Sorry it took so long to get back to you i had to leave.
 

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Here was the story given to me. Apparently according to him electronic fuel injection means that the coil pack gives power to the injectors. When the coil pack went bad it was not giving power to the injector and now the injector leaks down causing the miss. Now that i have had my good laugh for the day its time to drive to the dealership and talk to the service manager in person.
And this guy does this for a living? Sad, so sad. I would love to be there, wiring diagram in hand, and have him explain how that can happen. I can only hope there's a miscommunication somewhere, otherwise, he needs to head back to school.
 

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I just hope you don't have a burned valve. A burned valve will cause the misfire. The chrysler 3.0,3.3 and 3.8 suffer this problem in cylinders 5 and 6. The oil pump and water pump are in the front of the engine. So these two cylinders suffer heat problems. The exhaust valve runs hotter then the rest causing them to burn a hole in them.
A compression test will verify this. If that cylinder is pumping about 50 psi and does not increase pressure when oil is squirted into the cylinder, the head needs removed to replace the valve.

Another way to check for valve failure is with a dollar bill. Put it up to the tailpipe holding one end of the dollar. It should always blow the dollar outwards as the vehicle is idling. If it sucks it into the tailpipe, you may have a bad valve. This only checks for exhaust valve failure.
 

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“Another way to check for valve failure is with a dollar bill. Put it up to the tailpipe holding one end of the dollar. It should always blow the dollar outwards as the vehicle is idling. If it sucks it into the tailpipe, you may have a bad valve. This only checks for exhaust valve failure.”

What about using a vacuum meter. Doesn't this detect a bad valve fairly well.
 
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