2015 civic si

[dwright17]

That makes sense. I’ll load it up after work and log my drive home. Similar time to last night. Thank you again

[CalibratEd]

Sounds good. No problem.

-Ed

[dwright17]

alright i logged my drive home... for the first few minutes it was fine then the surging started again. you will see alot of it as i got caught in a long line at a red light. but then near the end of the drive it seemed to clear up...

[CalibratEd]

I made some more fuel adjustments. I also saw that it hit Vtec a few times. When it hit Vtec it leaned out.This makes sense as the Vtec tables are not tuned. I adjusted the Vtec engagement points to be the same at 5500rpm. For some reason the low point was set to 3300rpm.

Load the calibration and create a new log.

- Ed

[dwright17]

okay here is my drive home. still some surging but its defiantly getting better.

[CalibratEd]

I made some adjustment to try and figure out what is causing the surging.

-Ed

[dwright17]

here is todays log. still some surging while parled but it seems to clear up a bit quicker

[dwright17]

*parked
and idling

[CalibratEd]

Its strange that it is surging.The fueling is good. I adjusted the timing at idle to see if that fixes the issues. I would also double check if you have any vacuum leaks. If you turn on the car and let it warm up, does it surge? Does it only surge when you drive it around?

-Ed

[dwright17]

Only surges when driving around and coming to stops. Never on the initial start up. I will check on the vacuum leak but it just started with this batch of tunes. Maybe I’ll go back to the maf room I was using before and see if it stops

[CalibratEd]

Only surges when driving around and coming to stops. Never on the initial start up. I will check on the vacuum leak but it just started with this batch of tunes. Maybe I’ll go back to the maf room I was using before and see if it stops

That would be a good idea.

- Ed

[dwright17]

loading your revision now. i will start the datalog right when i turn it on so you can see warm up.

[CalibratEd]

It could also be that the closed loop tables need fine tuning or the o2 sensor is going out. When its surging the fuel status changes back and forth from Open - Cold to Open - Driving Conditions. Any time it switched to Open - driving the AFR goes lean, Timing is pulled and the Injector duty cycle goes to 0.

- Ed

[dwright17]

i have attached a log for your revision in which i still experienced some surging but it was minimal. i also attached a log of the maf tune i used before i made this thread and got in contact with you and the tune itself. the only change i made to the tune vs what i was using before is the fuel density setting if that makes a difference. there was intense surging in the maf tune compared to your tune that im sure you will see. i will experiment with a factory reflash or tomorrow to see if that eliminates it. in the meantime i hope these can help you help me determine if this problem is software based or hardware based. going to research vacuum leaks and o2 sensors tonight. thanks again for all of your generous help. so odd of this problem to pop up i have not experienced anything like it.

[CalibratEd]

In the MAF datalog I see the same fluctuation between open loop statuses.

Load this revision and create another log.

-Ed