MAP sensor issues?

Tiny
PAGE0210
  • MEMBER
  • 2001 HONDA CIVIC
  • 1.7L
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 220,000 MILES
Stumped again. My MAP sensor went bad about a month ago. I would hit the gas and it would bog down, hit the gas, big down and almost stall, after doing this for a while it would run okay for a while then repeat. I unhooked the MAP sensor, and it solved that issue, but another arose. When I hit 3,000 RPMs exactly, regardless of the gear my car will rev and not change gear. I have to slowly get to just below 3,000 and let it shift. Think of a waa waa waa waa rev noise at 3,000. I have changed the MAP sensor, and once again it solved the rev issue but now it's bogging down when I hit the gas again. I'm not sure where to go from here.
Friday, September 29th, 2023 AT 3:59 PM

11 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,101 POSTS
Hi,

Have you checked for diagnostic trouble codes to see if there are codes related to the MAP sensor again? I've seen a lot of new, aftermarket parts that either don't work out of the box or last a short period of time.

If you haven't, that is the first thing I would suggest checking.

Here is a link that explains how to test all modules for codes:

https://www.2carpros.com/articles/can-scan-controller-area-network-easy

Let me know.

Joe
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Friday, September 29th, 2023 AT 10:34 PM
Tiny
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I did a scan. The MAP sensor reads 5.1 at idle but then it spikes up to 15 to 17 and shakes like it will stall.
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Sunday, October 15th, 2023 AT 3:46 PM
Tiny
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I also have an under fuel system status: open loop due to insufficient engine temperature.
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Sunday, October 15th, 2023 AT 3:49 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,101 POSTS
Hi,

As far as the MAP sensor is concerned, that is way higher than I would expect. At idle, it should be approximately.5 to 1.5v. Your readings are extremely high. Is this the new sensor?

As far as the open loop, it sounds like the engine isn't reaching a predetermined temperature within a given amount of time. Open-loop control systems do not rely on feedback from sensors to make real-time adjustments. Instead, they operate based on a predetermined set of inputs and assumptions by the manufacturer.

On the other hand, a closed loop uses feedback from the sensors to continuously monitor and adjust the operation of the system in real time. This is what you want when the engine reaches operating temperature.

Do you have a code related to the open loop/temp indicator? Does the engine actually reach operating temperature?

Let me know.

Joe
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Sunday, October 15th, 2023 AT 7:08 PM
Tiny
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This is what I'm getting now. There is also a very distinct whistle coming from somewhere I haven't pinpointed yet.
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Sunday, October 15th, 2023 AT 11:45 PM
Tiny
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  • 18 POSTS
This is all I can get for the open loop.
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Sunday, October 15th, 2023 AT 11:48 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,101 POSTS
Hi,

Was that checked when the engine was cold? It indicates the engine is operating at 86F. Either the engine was checked immediately after start-up, or the coolant temperature sensor is bad.

Let me know.

Joe
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Monday, October 16th, 2023 AT 7:21 PM
Tiny
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It was right after startup, after it warms up it switches to "open loop due to system failure"
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Tuesday, October 17th, 2023 AT 10:31 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,101 POSTS
Hi,

It should be in an open loop when first started and once a predetermined temperature is reached, it goes into a closed loop. That doesn't make sense to me. Are you able to check the engine coolant temperature when it reaches operating temperature?

Let me know.

Joe
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Wednesday, October 18th, 2023 AT 5:15 PM
Tiny
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It floats between 175 and 180.
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Friday, October 20th, 2023 AT 12:25 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,101 POSTS
Hi,

The temperature is a little low. It should be 195F or more. You may want to consider replacing the thermostat to see if that allows it to reach operating temperature. Or, you may have already done that.

Let me know.

Joe
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Friday, October 20th, 2023 AT 2:28 PM

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