Unbalanced engine

Tiny
FULTONMAN
  • MEMBER
  • 2002 DODGE DAKOTA
  • 3.9L
  • V6
  • RWD
  • AUTOMATIC
  • 71,500 MILES
The last time I had in to the dealer, they told me that the 3.9 L was an unbalanced engine. What does that mean?
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Thursday, June 9th, 2016 AT 5:51 AM

8 Replies

Tiny
HMAC300
  • EXPERT
Because of the firing order the crankshaft is not in rhythm as engine fires so they balance it with torque converter and harmonic balancer to bring it in tune.
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Thursday, June 9th, 2016 AT 6:06 AM
Tiny
FULTONMAN
  • MEMBER
If the converter and harmonic balancer are acting up, would this create an issue sitting at traffic lights wanting to stall and rough acceleration? Has only happened twice in two months.
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Thursday, June 9th, 2016 AT 6:15 AM
Tiny
KEN
  • ADMIN
No, if the flywheel or harmonic balancer were the problem it would be constant. It sounds like you have a misfire problem, have you changed the spark plugs recently?

Here is a guide to help you

https://www.2carpros.com/articles/how-to-tune-up-a-car-engine

Let me know what you find.

Best, Ken

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Saturday, June 11th, 2016 AT 2:08 PM
Tiny
FULTONMAN
  • MEMBER
Hi Ken. Today, the truck ran great until I got Into stop and go traffic. The rpm's dropped down to probably 600. Had to put into neutral. It did not want to accelerate when back in drive. I do believe I heard popping (possibly misfiring of plugs). Ran bad. I pulled in to a gas station and allowed it to idle for ten minutes. Ran great after that. When the Dodge dealer ran the engine analysis in April, they did not seem to believe that the plugs needed to be replaced. I took them at their word. There were no trouble codes either. I gave up years ago working on engines. I would not be surprised if the link you sent to me is the problem. The fact that it would not accelerate and had popping sounds, I would imagine it is a firing issue.

Thanks again

Tom
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Saturday, June 11th, 2016 AT 5:54 PM
Tiny
KEN
  • ADMIN
It could be the fuel pump pressure issue as well, please check this link for more information

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

Let me know what you find

Best, Ken
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Saturday, June 11th, 2016 AT 8:21 PM
Tiny
HMAC300
  • EXPERT
You can easily check the harmonic balancer, draw a chalk line across it and the pulleys then start engine and give it a quick rev if chalk line moves on balancer the rubber has broken and weight is just moving on you
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Sunday, June 12th, 2016 AT 6:18 AM
Tiny
FULTONMAN
  • MEMBER
Ken, I found out yesterday that my Dakota has a problem code P0172 "system too rich on bank one". As I think I understand, that is the side that has the number one cylinder in firing order. To me, it makes sense. Correct me if I am wrong, but not enough o2 is mixing with fuel, not enough torque is being produced on the downstroke of the Pistons, this would equate to sluggish / non responsive acceleration, if I have the sensor replaced which is down on the bottom left side of the block, have all vacuum hoses checked and have mass airflow sensor cleaned. Do I have a good chance at this fixing my issue?
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Monday, June 13th, 2016 AT 4:22 AM
Tiny
HMAC300
  • EXPERT
Check your fuel pressure with a gauge if it's to rich on onebank then good chance whole bank is running poorly causing your problem. quit trying to overanalyze.
https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator
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Monday, June 13th, 2016 AT 6:42 AM

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