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Check Engine: Misfire

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Justin_97DSM

Probationary Member
7
1
Jun 19, 2019
Akron, Ohio
I bought my Eagle Talon two weeks ago, knowing it had misfire issues from the previous owner. I want to see if anyone had experienced this and/or knew what to do. When driving it, it doesn't misfire, but it posts all 4 cylinders misfiring. I'll post the codes. Thank you.
 

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The way I see it is that all cylinders are sharing something that causes it to set misfires codes. I would check first fuel trim, cranks/cam signals. Depending what I would find would dictate the direction to go. Second I would pull the plugs and measure the gap and do a visual inspection. Third I would do is check compression while I have the plugs out, to make sure we don't have some issues with mechanical timing. Forth I would grab a bear and start analyzing the data that I have on my hands.
 
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to get back on topic

if the check engine light is flashing when it missfires, its probably the ignition system.

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Fourth I would grab a beer and start analyzing the data that I have on my hands.

Surprised no one touched that to claim a Grammar Nazi badge, too distracted by the bear in the room I guess, haha
 
Is your car a turbo model or non turbo? if its a turbo model a 1g cas in a turbo model can set a random misfire code.
 
The thing is, the check engine light does not flash. And the previous owner replaced the plugs and sensors with OEM parts. I'm starting to think it may be the computer. But I am trying to see if it could be something else before I spend 200-400.
 
have you checked the compression?

take a look at the wiring thats close to the EGR tube. The tube gets hot and it can f*** up the wires.
Check the EGR valve too. Make sure it isn't stuck open from carbon build up.


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I will say this. You guys made me laugh. I will also say that in my 12 1/2 year career as a tech I have changed a pcm like 3 times. I will also add that 2 of them never fixed the problem. One was on a 4 liter jeep, had p0201, had pulse but still missed. I told my self that it had to be a computer as I already moved the injector. Only by a chance that I was moving wires around where a miss turned into dead miss, the valve cover bolt in the back rubbed thru the wires and was massing signal wire up. Second was on e250 and that van would just stop running and voltage on the scanner would go to 7.1 volts. Though that it was very strange, checked the usual things. It turned out to be, again by chance I touched one of the ignition coils and the truck would run better, ignition coil spiking the pcm. So with that being said, I never suspect a pcm. It is always the last thing on my mind. Also the third pcm was actually bad. It was on one of those B2500, it had no 5 volt referance.
 
I would do a compression test. By doing it you will see if your ngine is even worth fixing. If all numbers are good than move on, if they are all low then check mechanical timing. I would also look into crank/cam sensors. First look for corolation or sync with each other in the scanner. They need to be sync. Then you need to hook up a scope on the signal wire and look at the pattern of the crank sensor. You will have to find a know good pattern. You can use iatn website for that. If that checks out, then I would check into fuel trims and fuel pressure. I find it hard to believe that the car is running good and yet sets misfire codes. I would also check for 5 volt referance and powers/grounds to the crank sensor. Notice that you are not actually changing anything, it's relatively easy and simple tests. Most of these things you can find how to on you tube. We need to start eliminating things to gain some traction to keep going.
 
......... I will also say that in my 12 1/2 year career as a tech I have changed a pcm like 3 times...........................

I was thinking the same thing earlier, i have never seen a 420a PCM go bad.

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download this, its the MFI section of the factory service manual: It has all the sensor checking procedures.
http://www.mediafire.com/file/g71rpcrjbzkozep/420a_RS_GS_MFI_TroubleShooting.pdf/file

here is the link to the main directory if you want any other reference material. http://www.mediafire.com/folder/ac51jwwa3g1n1/automotive_manuals
 
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