Mechanics

BAD ACCELERATION

Honda Civic

My 1997 Honda Civic doesn't accelerate when I push the throttle down normally (it bogs down). If I push it down very slowly it will accelerate fine. Anybody have any ideas?
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Kevroll
October 30, 2007.




Engine?
Miles?
Manual / AT?

Let us Know on the info.

Tiny
Fisherman
Oct 30, 2007.
Car is a 1997 Honda Civic EX, 1.6L 4 cyl, 5 spd, ac, power, 187k mi.

Thanks
Kevin

Tiny
Kevroll
Nov 1, 2007.
Hello !

Start checking the TPS (check the voltage with the wide open throtle)
Then the EGR for carbon build-up (clean it)

And the Maf sensor.

The Mass Air Flow sensor is crucial to the fuel systems operation. This is the sensor that the engine computer uses to measure how much air is entering the engine so that it may properly deliver the proper amount of fuel. A dirty MAF sensor hot wire may cause several problems to include: difficult start, poor acceleration, pinging, rough idling, to name a few. This whole procedure should take you less than ten minutes.

Its the check engine light on?

Check them and get back with the results.

I`l get some info on the how to and I`ll post it later if you don`t know how to test the sensors.

BTW I saw that you donate!
Thanks a lot! We appreciate that!

Good Luck!
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Tiny
Fisherman
Nov 1, 2007.
Yes, thank you for the info I was thinking of the mass airflow sensor too! And no check engine light.

Kevin

Tiny
Kevroll
Nov 2, 2007.
Hey Kevin!
In this case your car uses a MAP sensor (Manifold Absolute Pressure)

a MAP sensor simply compares the pressure difference between 2 chambers. One chamber is sealed and used as the reference pressure (usually a vacuum) and the other chamber is connected to the intake manifold (usually by a vacuum hose). When the pressure in the intake manifold changes, this will change the voltage signal going back to the ecu from the MAP. A pressure drop will cause a voltage drop. This voltage is only interpreted as manifold pressure. The ecu will also need to use the signals from the rpm sensor and air temp sensor to calculate air mass, pressure alone is not enough. Plus any vacuum leaks on the hose, or indeed any other vacuum leaks on the manifold, will affect this sensor's signal.

After locating the MAP sensor, disconnect its wiring harness.

To test the MAP sensor, run jumper wires between its terminals and wiring harness per the service manual's instructions. Turn the ignition to the ON position and take a voltage reading. Spec for this MAP is about 4.5-5.0 volts.

With the engine running and warmed up, take another voltage reading. It should differ from the non-running number and fluctuate when the engine is revved. If not, verify that the vacuum line isn't damaged or blocked.

If the vacuum line checks out, the sensor is likely faulty. Replace the bad MAP with a new one by connecting the vacuum hose and wiring harness, then securing the sensor to its factory location.

I would check for vacuum leaks and check the sensor good.
________
Let me know how are you doing!

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Tiny
Fisherman
Nov 2, 2007.
I'll take a look at all that, thanks for all the great info it's really helping me understand fuel injection.

Kevin

Tiny
Kevroll
Nov 3, 2007.
Hello again, when I take the voltage reading I am getting nothing. To make sure I'm doing it right do I take the reading from the two terminals of the female plug? And is it left unplugged while taking the reading? This is what I am doing. And to also be sure the MAP sensor is located on the fuel injector rail yes?

Thanks
Kevin

Tiny
Kevroll
Nov 8, 2007.
Forgot to mention that the car runs perfect when cold then bogs down a few minutes after running.

Thanks again,
Kevin

Tiny
Kevroll
Nov 8, 2007.
Hello Kevin!
How are you been?
Well lets continue, i think that its working good when cold because of the cold start valve (extra fuel when cold)
here a picture of the MAP sensor:


http://www.2carpros.com/forum/automotive_pictures/576_civic_map_sensor_1.jpg



the complete picture:


http://www.2carpros.com/forum/automotive_pictures/576_civic_97_1.jpg



I`ll be back with the spec.

Tiny
Fisherman
Nov 8, 2007.
Hey Kevin..
You should run "jump" wires to the MAP sensor to be abble to get readings here is the spec:


http://www.2carpros.com/forum/automotive_pictures/576_civic_971_1.jpg



here is the connector:


http://www.2carpros.com/forum/automotive_pictures/576_civic_9712_1.jpg


Tiny
Fisherman
Nov 8, 2007.

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