Bad pcm?

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Bad68chev
Newbie
Posts: 1
Joined: Thu Oct 15, 2020 8:00 pm

Bad pcm?

Post by Bad68chev »

Can anyone tell me if this looks like a bad pcm? Car is a 2012 Chevy sonic, has random misfire codes. Will run smooth then out of blue runs terrible, misfires will be on diff cylinders, sometimes cyl 2, other times cyl 1, sometimes 2 and 3 at same time according to scan tool misfire counter.I took a sample of injector control signal, sometimes it has an extra pulse which is real short. This is just cyl 4. I’m kinda new to using oscilloscope FYI.
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C47A3FCC-6988-4372-881F-E92679406130.jpeg
379C5F0C-F02C-49F2-8471-B581AB3903BD.jpeg

vasek
TwoWaves
TwoWaves
Posts: 58
Joined: Tue Feb 17, 2015 7:27 pm

Re: Bad pcm?

Post by vasek »

Hi.
This mode of operation of the fuel injector control driver is not a malfunction.
This is the ECU's response to the need to stabilize the crank-shaft rotation.
You need to look for the cause of uneven engine operation.
Attachments
CHEVI 1.6 _ NG.PNG

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