Negative long and short term fuel trim above 14% all the time

[codemaster2]

Hi guys, I am always getting a negative LTFT and STFT -16% and -19% respectively on average on my Honda civic 2007 with the R18 engine. Everything is stock.

I have change air filter, mass airflow, 02 is ok. Please any one with an advise
Eficu

[EFICU]

Hi guys, I am always getting a negative LTFT and STFT -16% and -19% respectively on average on my Honda civic 2007 with the R18 engine. Everything is stock.

I have change air filter, mass airflow, 02 is ok. Please any one with an advise
Eficu

You are running Hondata FlashPro with a calibration in it correct? Or are you saying it is doing this on the OEM calibration?

If you are running FlashPro, we would need to see the calibration you're running on and a datalog to show the issue. It should be something as simple as fuel adjustments needed, shouldn't be a mechanical issue, but it could be.

Let us know.

[codemaster2]

Hi Eficu, I am not running flashpro, dont even know what that mean, my car is stock about 200k miles, I ask this question in the flashpro section becuase I coudnt find an Honda civic section in this forum, sorry about that.

Please help me, my fuel trim is always negative, it bothers me, I get -14% to -20% all the time on both LTFM and STFM,

Please

I am still on stock calibration

[EFICU]

The FlashPro is the device from Hondata that allows us to flash the ECU with new calibrations. Without it, there isn't really much I can do for you and the rich fuel trims. I've never seen a datalog from an R18 in stock form, so I don't know what common fuel trims are for those for stock. You could try to take it to a shop or dealer and have them do a diagnostic on it perhaps, though I don't know that it would yield too much information, but you never know. Without the Hondata FlashPro device though, I can't look at or control any of the fueling to get the trims better for you.

[codemaster2]

OK, thank, If the flashpro device can fix my rich fuel trim, then I need to buy it I guess.


Eficu

[EFICU]

I’m not entirely sure it will, but it’s only way we can adjust the fuel to try to get it better for you. Short of having a mechanical diagnostic done to check for an issue, it’s the only way to access the ECU to make adjustments.

[codemaster2]

Suppose I have a mechanical issue like worn piston ring that causes a rich fuel trim, can I use flastpro to adjust my parameters such that my engine runs efficently?

Eficu

[EFICU]

In theory if you have a mechanical issue we can sort of band-aid it to adjust for the issue. Piston rings shouldn't cause a rich condition, but say for the sake of this conversation something like that was the culprit, we would be band-aiding the issue essentially to get the fuel trims inline. The only reason why I mention it might be a mechanical issue is to make sure we understand that buying a FlashPro doesn't mean the problem will be solved, it's just a tool to dial in the air fuel ratio. I've seen Civic Si's with very high fuel trims, so the trims could be perfectly normal and just needs to be tuned. I don't mean to make you nervous like you have a mechanical issue, just making sure we're on the same page as far as what getting a FlashPro allows us to do. Since you car is stock, and the fueling is trending rich, it could be something as simple as scaling the MAF sensor for your engine and you'd be good to go. The OEM calibration in your car is designed to work for millions of Honda Civics sold, so the fuel trims are there to keep it inline, we can tune it to make it ideal for your specific car basically using the FlashPro as a medium to do so. But if there is an underlying mechanical issue, there might only be so much we can do.

[codemaster2]

Hi Eficu, having done (i think) all the mechanicals and sensors checks that could cause my stock R18 honda civic 2007 to run rich all the time and yet finding none, I think I am now ready to go the Hondata route to recalibrate my ECU and resolve this issue once and for all.

Please how can I get this device, I am based in Lagos Nigeria Africa, how much is it, what information do I need to provide so that I am sure I am getting the right one for my car.

Thanks, I am looking forward to hearing from you.

[Spunkster]

What is your ECU part number?