Misfire

Tiny
DIVIDES
  • MEMBER
  • 2013 FIAT 500
  • 4 CYL
  • 2WD
  • MANUAL
  • 106,000 MILES
Bought it with a misfire. Had an extra set of new coils so I installed them still firing on cylinder 3. It had codes misfire on all but now I got it down to 1, cylinder 3. Changed the plug from 3 to 4, still same code, even though the plug in 3 looked different than 4 for some reason. It also had some fuel on it, on number 3. Is it common to have bad injectors on these cars? I also heard that a bad VVT for that cylinder could also cause same thing. Car runs rough. If you hit it hard it smokes black from all the unburned gas.
Monday, June 7th, 2021 AT 4:41 PM

12 Replies

Tiny
DIVIDES
  • MEMBER
  • 910 POSTS
Runs better with the new coil, doesn't stall, but still not right. Can I test these with the light tester used at the injector harness?
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Tuesday, June 8th, 2021 AT 2:34 PM
Tiny
BORIS K
  • MECHANIC
  • 836 POSTS
Hello,

Is the engine fitted with the multi air system? If yes first scan the PCM for codes. Next check oil level and oil quality. When was the engine oil replaced? Was the correct grade used? The multi air system work on hydraulic pressure to operate the intake valves and is very sensitive to low oil or poor oil quality.

How the system works:

https://youtu.be/Td9Gz_h7Qpg

Please let us know how you get along.

Cheers, Boris
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Wednesday, June 9th, 2021 AT 6:21 AM
Tiny
DIVIDES
  • MEMBER
  • 910 POSTS
Hmmm, didn't know that. Will 5w-30 work? I can change it today.
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Wednesday, June 9th, 2021 AT 6:24 AM
Tiny
DIVIDES
  • MEMBER
  • 910 POSTS
These pulled up mot sure if they are related. I deleted them and they went away.
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Wednesday, June 9th, 2021 AT 6:33 AM
Tiny
DIVIDES
  • MEMBER
  • 910 POSTS
Also, I got the quick lit tool and I touched all injector bodies and all firing correctly.
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Wednesday, June 9th, 2021 AT 9:53 AM
Tiny
DIVIDES
  • MEMBER
  • 910 POSTS
Also swapped spark plugs and coils into another cylinder and tested for spark with the light and its there.
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Wednesday, June 9th, 2021 AT 10:19 AM
Tiny
DIVIDES
  • MEMBER
  • 910 POSTS
How do I remove the VVT on this cylinder, don't see bolts. Changed the oil and it has gotten better. I think the VVT maybe dirty.
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Wednesday, June 9th, 2021 AT 10:28 AM
Tiny
DIVIDES
  • MEMBER
  • 910 POSTS
If I delete the code it gets a bit better, still 303 and sometimes 353 ignition coil.
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Wednesday, June 9th, 2021 AT 10:31 AM
Tiny
DIVIDES
  • MEMBER
  • 910 POSTS
Compression 130 on cylinder 2 and 35 on cylinder 3, I guess it's shot.
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Wednesday, June 9th, 2021 AT 1:50 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
Hi,

Did you check the compression both wet and dry? That is to determine if it is a ring issue or a valve/head gasket issue. Based on the mileage, I have a feeling it could be a gasket issue.

Here is a link that explains how to test compression. Do it both dry and wet. Well, you already did it dry. Add about a tablespoon full of oil to cylinder 3 and recheck compression and let me know the results.

https://www.2carpros.com/articles/how-to-test-engine-compression

Take care,

Joe

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Saturday, June 12th, 2021 AT 10:15 PM
Tiny
DIVIDES
  • MEMBER
  • 910 POSTS
Just dry compression, removed fuel pump relay, removed plugs from cylinders 2 and 3, one was great the other was low. I added a tablespoon but didn't measure after it, though it may bring it back up, but it's still misfiring. Am going to sell it like it is, not worth replacing either. Thanks for all the help.
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Sunday, June 13th, 2021 AT 6:09 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
Hi,

You are very welcome. Please feel free to come back any time in the future if you have questions.

Take care of yourself,

Joe
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Sunday, June 13th, 2021 AT 6:35 PM

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