Boggs down when gaining speed

Tiny
CHASELAKEY0
  • MEMBER
  • 2009 DODGE CHARGER
  • 5.7L
  • V8
  • 2WD
  • AUTOMATIC
  • 215,000 MILES
If you drive the car slow with barely any gas but reasonable acceleration it won't bog down, but give it 25 percent on the gas or more the car shakes and shutters. If you floor it sometimes it will just bog out unless you are in the power band range 30 and 60 area you can floor it no problem just gaining speed. But I recently put in on the dyno and you can feel the transmission hard shift downshifting from 5th to 4th only have no misfires new computer dyno tuned went through 3 camshaft sensors to make sure. Oil pressure sensor replaced wiring checked out fuel system checked. Only thing I haven't checked is the transmission. I just wanted to know if my car will bog out not slip at all because of the transmission and you can't take off the line trying to race anybody.
Thursday, June 10th, 2021 AT 7:45 PM

6 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,700 POSTS
Hi,

If the transmission is slipping, the engine RPMs will increase without the vehicle speeding up at an equal rate. A bog normally indicates a lowering of the RPMs.

Have you checked the transmission fluid to see if it is full and clean? Also, are there any diagnostic trouble codes?

Let me know.

Joe
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Friday, June 11th, 2021 AT 9:57 PM
Tiny
CHASELAKEY0
  • MEMBER
  • 4 POSTS
No codes and doesn't slip it only bogs with increase of speed.
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Saturday, June 12th, 2021 AT 6:57 AM
Tiny
CHASELAKEY0
  • MEMBER
  • 4 POSTS
Maybe a torque converter?
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Saturday, June 12th, 2021 AT 6:57 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,700 POSTS
Hi,

I wouldn't think the converter would cause an engine bog. The heavier you are on the throttle requires more fuel and air to the engine. If it bogs when you request more power, the first thing for me is the fuel pump is weak or there is an air restriction to the throttle body.

Have you confirmed fuel pressure? Also, do you have a live data scan tool?

If you have a live data scan tool, let me know what the short-term fuel trims are at operating temperature. Also, if you haven't, you should check the fuel pressure. There could even be an issue with a filter restricting fuel.

Here is a link that explains in general how to test fuel pressure:
https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

Let me know if this has already been done and the results.

Take care,

Joe

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Saturday, June 12th, 2021 AT 8:46 PM
Tiny
CHASELAKEY0
  • MEMBER
  • 4 POSTS
I have done a fuel pressure test it sits at 52 53 PSI and I don't have a scan tool they have checked my air to fuel ratio already from what I was told when I put it on a dyno to have it tuned.
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Monday, June 14th, 2021 AT 10:15 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,700 POSTS
Hi,

Fuel pressure is low. Non SRT-4 fuel pressure specification is 407 KPa +/- 34 KPa (59 psi +/- 5 psi). SRT-4 fuel pressure specification is 552 KPa +/- 34 KPa (80 psi +/- 5 psi).

If there isn't enough pressure, it can cause a bog.

Let me know.

Joe
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Monday, June 14th, 2021 AT 8:22 PM

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