Honda City 2006 iDSI, bad fuel economy after engine tuning

talhazia878 (Talha Zia) 2018-09-23 19:20:50 +0500 #1

Hi, I am a user of Honda City 2006 iDSI, it was giving 17+ average on motor way and 15+ average in city with AC off, but after tuning it is giving bad fuel average, 11 in city and 13 on motor way,
In tuning spark plugs were changed and throttle was also cleaned,
I havent tried reseting ECU ? Is there anyway of resting ECU at home ?
Moreover after engine tuning its rpm are not stable in idle position. I am thinking maybe there is issue regardings its ECU,

needou (needou) 2018-09-23 19:35:50 +0500 #2

it does not look ecu issue,,, throttling body cleaning may not done properly. furthermore, un-stabling the RPM is also the symptom of ignition coils performance. in IDSi there are 8 coils 4 front and 4 back. any one of set can be faulty.
please get it check. but if rpm was stable before cleaning the throttling body then make it clean again.

talhazia878 (Talha Zia) 2018-09-23 20:20:58 +0500 #3

Shouldnt I give it a try for ECU resetting ?? Rpm idle fluctuation starts sometime and most of the time it remains stable. Whenever I press clutch rpm boosts to 1800, It was not the case before. Maybe ECU was not calibrated ok

talhazia878 (Talha Zia) 2018-09-23 20:24:03 +0500 #4

Another interesting thing is that, I filled the petrol tank at 41 liters, It drove 330 km in first upper half of fuel tank and at 451km, I had to refill it again to 39.14 liter, there is a significant low milage in the lower half fuel tank

needou (needou) 2018-09-23 23:36:01 +0500 #5

get it reset if you have doubt on it. it does not have huge cost.

also check fuel sensor. (although it is not important in manual cars)

wish you good luck

needou (needou) 2018-09-23 23:44:11 +0500 #6

yes it is usual,,,, it has actually level sensor in fuel tank. some time level sensor drop its value upon restarting the engine/car.

dont worry about it. it has 45 liter fuel tank but normally fuel light turns on at just 35 liter consumed.!!

correct way to check: get fuel up your car on auto filling. fuel dispenser cut off supply automatically when fuel tank get filled. then run the car and on/off the switch after every 50 kms. just before being half of the tank, turn off engine for i minute at-least, (full turn off the car not only engine.) and restart. you can see that needle of fuel is lower now.

am not auto engineer its just my observation what i also checked, an expert may guide you perfectly

babaralinawab (babaralinawab) 2018-09-24 07:35:56 +0500 #7

My idsi always dropped milage after changing spark plugs

dayrider (dayrider) 2018-09-24 09:55:14 +0500 #8

Which spark plugs did you put in, they could not be the correct ones? secondly, your throttle body cleaning if done right, needs to be followed by an ecu reset

Mirza967 (Mirza967) 2018-09-24 11:22:28 +0500 #9

After ghusl e miyat of throttle body......the tps settings are disturbed.......take it to Honda and they will recalliberate the tps then ur car will be normal......however u can try resetting the ECU buy disconnecting negative terminal of battery for 10 mins and reconnecting it and then start your car for 20 mins without any ac and lights and other electrical equipments....after 20 mins turn on the AC for 10 mins ....then AC +headlights for next 5 mins..... hopefully this relearns the idle....and next time Don't clean ur TB unnecessary

Mirza967 (Mirza967) 2018-09-24 11:34:24 +0500 #10

Moreover Don't put your foot on throttle pedal during idle relearning

talhazia878 (Talha Zia) 2018-09-25 00:01:18 +0500 #11

Today, I reset the ECU, as per this method. I am felling a difference. I got the tank full, lets see what would be the average this time.
I am getting stable 800 idle rpm without AC, but with AC I am having slight fluctuation 800 to 1200 rpm. Is it ok ??

talhazia878 (Talha Zia) 2018-09-25 00:04:19 +0500 #12

Is idle relearning helpful in improving milage issues ??

dayrider (dayrider) 2018-09-25 09:48:46 +0500 #13

yes
and yes, it is also helpful in improving mileage

talhazia878 (Talha Zia) 2018-09-25 11:48:42 +0500 #14

Mirza967 (Mirza967) 2018-09-25 12:15:30 +0500 #15

Your iacv is stuck so it's not compensating the rpm when ac is on...... moreover when ac is on check for vacuum leaks around intake manifold and throttle body.... sometimes air is sucked in from butterfly spindles.......use some carb cleaner and spray on intake manifold and throttle body area with started engine...the point where on spraying engine sound changes....there is the vacuum leak

talhazia878 (Talha Zia) 2018-09-26 04:26:47 +0500 #16

Kindly, suggest me a good mechanic regarding IACV in Lahore, I use to visit Mr. Zakir Workshop opposite to saint anthony church, Mall Road

saad.bukhari1 (saad.bukhari1) 2018-09-30 02:52:40 +0500 #17

If ur rpm fluctuate after turning on the ac then u better change the throttle body... Buy some fine quality quabli.. its not expensive hardly of rs. 2000