New K series owner with some issues. Datalogs inside!

[matt94z]

Ok, so first off ill say that I am new to K series and have never tuned a car. I just picked up an 01 EX with a K20a2 swap. The trans was locked up when I bought the car, so I never test drove it. I put a used RSXS trans in it and when I finally drove it, I noticed a few problems.

1.) Primary O2 wasnt responding, so I bought a new OEM RSXS sensor (wideband). That issue is fixed.

2.) There is a horrible vibration (feels like a wheel is about to fall off) in the pass front when turning the wheel to the left. Its more noticeable at higher speeds and seems like it is more noticeable after a hard acceleration. I thought it was an axle, so I sent the axles back to Gator Racing to have them rebult. That did not fix the problem. Im wondering if this could be the diff getting ready to take a dump?

3.) The headlights and dash lights dim randomly when theres a load on the engine. Im not sure if this has something to do with the ELD. I tried turning it off in Kpro and it didnt make a difference.

4.) A short time after a full throttle pull, the car will start breaking up real bad. It does this at any TPS%. ie, theres no change if im light throttle or hard on the throttle. I also noticed that the speedo drops or bounces around when this is happening. I swapped the VSS out and no change.

5.) I took a few datalogs and my AFs are def too lean in the 14s at WOT!!

6.) at one point I got a error code for a "multiplexor communication error" Im not sure what this is...

The first datalog is with the tune stored in the Kpro files for 310cc, BC2's, Toda Header... etc. The car freakin rips with this tune! But still has all the above issues.

The Second datalog is with the tune that was in the ECU when I got the car. The kid I bought it from swears up and down that it ran great with this tune.... I surely doesnt now!

The 3rd tune is the BC tune again from the first log. The car did the breaking up / studdering in all of the logs.

The mods on my car are:

01 Civic EX K20a2
-37820-PRB -A06 / 2068-60456L-0B03
-Kpro 05001254 w/ latest sw version.
-BC stg 2 cams, springs and retainers, RBC cam gears
-RBC intake
-Comptech header
-3" Buddy Club exhaust
-Short ram intake w/ blox v stack and K&N
-I was told that this engine was rebuilt and has higher comp pistons, but I have no way to verify that.
-Stock 310cc injectors (I believe). They say RA17 BAH on them

[matt94z]

Any help on the tune would be greatly appreciated.

[Spunkster]

IF it does not relate to the ECU or hondata, I would have no idea what is causing it.

You have not posted the calibration.

[Hondata]

You have a major problem with the grounding and/or changing system. I would not drive the vehicle until you sort this out, as you are getting over 20V to the ECU.

[matt94z]

Thanks for the response, I was actually wondering if the trans to battery ground was in a bad spot. Im going to get some new ground cables tomorrow and try that. If the grounds arent the issue, do you think the alternator could be going bad? Does the alt have an internal voltage regulator?

Im attaching the tunes that Ive tried. The one marked stock tune is the one that was in the ecu when I got it, which made it run like complete garbage. The second one is the tune that I used from your files which makes it run awesome!

Thank you for your help, I am trying to get this car sorted out as soon as possible, as I plan on daily driving it.

[matt94z]

Update:

-The sputtering / breaking up and dimming lights problem has been fixed. It was the battery to trans ground, it must have been in a bad spot. I also added an extra hround cable from the vcover to firewall.

-I also fixed the vibration problem. Bought a new axle for 02 civic si and it was almost 2" shorter than the Gator Racing axle that was in there.

Now i just need a tune