95 Civic Ecu Reset Mpg
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Honda-Tech Member
Joined: Mar 2012
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From: orlando,fl
95 Civic Ecu Reset Mpg
Due to a small leak near my ecu which was casuing it to get damp and not start I started taking the ecu out of the car and I noticed my mpgs and even driveability is better when i replug the ecu in. When it was left in and had learned the parameters and whatnot it drove ok but felt sluggish and definitelt was using more gas. Ive noticed like a 10mpg difference so far and better torque for sure.
Im wondering what I could look at that the ecu may be reading causing it to run rich or poorly.
Car is pretty much stock has stock d15b7 new head on it, new stock injectors, new walbro fuel pump, new fpr, new fuel filter, new dist and spark plugs. Everything mechanical is in good shape and moslty new and car drives good even when ecu learned parameters besides it feeling more sluggish and using more gas.
Im wondering what I could look at that the ecu may be reading causing it to run rich or poorly.
Car is pretty much stock has stock d15b7 new head on it, new stock injectors, new walbro fuel pump, new fpr, new fuel filter, new dist and spark plugs. Everything mechanical is in good shape and moslty new and car drives good even when ecu learned parameters besides it feeling more sluggish and using more gas.
Thread Starter
Honda-Tech Member
Joined: Mar 2012
Posts: 281
Likes: 6
From: orlando,fl
Re: 95 Civic Ecu Reset Mpg
No im telling you the difference is night and day. With the ecu left plugged in the last couple weeks my car was using gas way more. I drive the same 250mile commute to work every week and I was averaging like 26-30mpg. When I realized the issue of why my car wouldnt start due to the damp ecu and I started taking it out my mpgs have been 33-36 and the car accelerates way smoother. Before I started unplugging it it was sluggish and unresponsive and now its not. These are pretty objective observations especially the mpgs.
Honda-Tech Member
Joined: Jan 2013
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From: The South - Roll Tide !!!
Re: 95 Civic Ecu Reset Mpg
There IS adaptation in a Honda OBD-1 ECU.
It is likely that you have a "psycho" O2 sensor... sending improper values to the ECU for efficient closed-loop operation. Short term and eventually Long term fuel trims will roll up exceptionally high one way or the other... in your case, what you are describing is to the positive or rich side... which ultimately affects fuel economy and performance. An exhaust leak ahead of the Primary O2 sensor can also create this issue. Unplugging the ECU resets the short and long term fuel trims so you are starting from zero each time.
In extreme cases, I have seen the effects that you are describing in as little as 60-75 miles... but it is typically more like 120-150 miles.
It is likely that you have a "psycho" O2 sensor... sending improper values to the ECU for efficient closed-loop operation. Short term and eventually Long term fuel trims will roll up exceptionally high one way or the other... in your case, what you are describing is to the positive or rich side... which ultimately affects fuel economy and performance. An exhaust leak ahead of the Primary O2 sensor can also create this issue. Unplugging the ECU resets the short and long term fuel trims so you are starting from zero each time.
In extreme cases, I have seen the effects that you are describing in as little as 60-75 miles... but it is typically more like 120-150 miles.
Thread Starter
Honda-Tech Member
Joined: Mar 2012
Posts: 281
Likes: 6
From: orlando,fl
Re: 95 Civic Ecu Reset Mpg
I recently replaced my O2 sensor with a Bosch unit i guess it could still be the cause? Header gasket was replaced also when head was replaced last year guess there could be a leak there somewhere
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