Odd fuel trim issue- Kpro on S2000

Ramocheese · Post by **Ramocheese** » Tue Apr 28, 2009 10:31 am

I installed my kpro this weekend on my '04 S2k. I swapped all of the sensors over, and loaded up the AP1 basemap. The car fired right up, and I got the car over to the dyno yesterday.

For the most part the car is dialled in. Under open loop the car runs and drives perfectly.

I enabled closed loop, and for the most part it runs pretty well, but there is one issue that I can't seem to figure out. As the car warms up, between coolant temps of about 140 to 170 as you give the car throttle the short term fuel trims will start skyrocketing in the negative direction. Under almost any kind of throttle input it will start counting very fast up to as high as -40%. Once you get off the gas it will shoot back to 0% and start doing it again as you give it more throttle input. Once the car warms up past around 170 degrees it clears up and the car drives perfectly again, with the short term fuel trims going at the most -8% or so, but it corrects itself as you drive the car.

It almost seems as if the O2 voltage is sticking when the fuel trims go out of wack, but I can't seem to do anything to correct it. With closed loop disabled the car runs perfect.

The car is completely stock even down to the stock cat and air box. The only changes are the cam/crank sensors and trigger wheels I had to swap, and the new IAT sensor.

I'll try to post some logs here when the car cools down and I get a chance to go somewhere.

Post by **Spunkster** » Tue Apr 28, 2009 10:39 am

calibration and datalogs showing the problem?

sinistrs2k · Post by **sinistrs2k** » Tue Apr 28, 2009 1:00 pm

Thats 3 S2000s with funky O2 sensor readings causing weird fuel trims. I wonder if we don't have something in common happening.

I just took a datalog of another weird issue mine is having and am about to post that in a new thread. I think it might show the weird O2 goofiness too. I wont load mine here so the OP can keep his thread clean and on his issue.

breiter56 · Post by **breiter56** » Tue Apr 28, 2009 8:33 pm

I thought I would chime in to state that I have just made observations of similar behavior on my '04. I will also work on getting a data log. Should I follow up by posting it here or start a new thread?

geoffrey70 · Post by **geoffrey70** » Wed Apr 29, 2009 6:34 am

I'm having this same issue give or take a few tiny details. I will post a datalog and cal when i get home from work to help gather info on it.

Ramocheese · Post by **Ramocheese** » Thu Apr 30, 2009 8:28 pm

I haven't saved any logs to upload yet, but as an update my O2 heater CEL came on, so I am just thinking it's a lazy O2 sensor. I'll confirm the heater circuit is actually dead this weekend when I get a chance to get under the car and get a new sensor swapped in.

If I still keep having this problem I'll get some logs up here.

Post by **Hondata** » Fri May 01, 2009 8:37 am

For the love of god people, rather than jumping on the me-too bandwagon give us some meaningful datalogs.

breiter56 · Post by **breiter56** » Fri May 01, 2009 10:29 am

I have tried a few times to upload a 3.9 MB *.kdl file with no success. Will you accept the file by e-mail, or help troubleshoot the upload problem? Thanks

geoffrey70 · Post by **geoffrey70** » Fri May 01, 2009 10:47 am

Hondata wrote:For the love of god people, rather than jumping on the me-too bandwagon give us some meaningful datalogs.

- KManager version (not 'the latest') - 1.3.4.0
- the calibration (as an attachment) - posted
- what sort of vehicle you have - 2003 S2000
- what sort of ECU you are using - PRB
- anything about the car which has been modified from stock which may affect the ECU - Exhaust, and test pipe
- a specific description of the problem- Bogging after short term fuel trim starts. Rough idle. Datalogs posted

Busy week at work, my apologies. I also needed to get a few datalogs and being that the problem is mainly cold starts, it took me some time. -Geoff

LMK if these are not sufficient.

geoffrey70 · Post by **geoffrey70** » Fri May 01, 2009 10:58 am

I have 4 more, but it will not let me post them. I'm guessing they're over 5mb.

Post by **Spunkster** » Fri May 01, 2009 12:23 pm

email them to support (at) hondata dot com

Post by **Hondata** » Tue May 05, 2009 8:15 am

The problem is that the o2 sensor response is very slow - about 4 seconds to cycle around stoichiometric. We're in the process if getting a S2000 in for further testing.

geoffrey70 · Post by **geoffrey70** » Tue May 05, 2009 9:46 am

Hondata wrote:The problem is that the o2 sensor response is very slow - about 4 seconds to cycle around stoichiometric. We're in the process if getting a S2000 in for further testing.

Thanks for the update. Let me know if there's anything else you need.

Post by **Hondata** » Fri May 08, 2009 11:06 am

We have the S2000 and are looking at the problem now. We'll keep you up to date with the results.

Post by **Hondata** » Mon May 11, 2009 10:00 am

We've made some changes to the calibration so that you can run with OBDII enabled, which helps closed loop operation. A beta version will be available shortly for you to try out.