Hondata

Background Info:
02 RSX-S, Turbocharged K20a2, 86.5mm, 9.0 CR
Walbro 255 in-tank, -8 feed, -6 return to tank, FPR

Went to get tuned this past Saturday and here's the problem i'm having... The first few pulls on the dyno seemed fine, A/F was pretty much were it needed to be. then the A/F started to be very inconsistent between runs with no major fuel changes to the map. Then the A/F at idle became very inconsistent... before one pull its 14.5 and the next its 16.5 and no changes were made to the map at all. Then everything stayed on the lean side... idle A/F was high 16's and when we'd make a pull it would drop to the high 12's and as soon as boost started coming up the A/F went lean.

We had the dyno's wideband hooked up, my brand new aem wideband sensor and a brand new primary o2 and they were all reading basically the same. We had plenty of fuel pressure throughout each pull... starting FP was 55psi and it would increase to around 68 @ 10psi and hold fine.

So we have fuel pressure and i can't believe 3 sensor would be bad so the first logical explanation would be the injectors gone bad, right?? A buddy of mine lent me his 750's from his car and i tried them out tonight and same shit happened... as soon as boost started, it would go lean. I even started dumping more fuel overall to the map... did 10% and even 20% overall. There was a big difference in the idle A/F but as soon as i would start to boost it would go lean again.

I then unwrapped all my injector wires to make sure everything was sound... which it was, so i re-taped everything up. I then proceeded to Erase the Security on the ECU... waiting a few minutes and then uploaded that last map we used on the dyno. went to the hwy to do some pulls...

Everything worked just fine... A/F stayed mid 11's under boost (11psi) and now the car runs great. Could it have been just that?? Has anyone experience that type of lean issue under boost before and not have it be a fuel delivery issue? Could there have been a bug in the ECU somewhere that would cause the car to go lean under boost??

I'm not sold yet... waiting for the problem to show its ugly face again :evil:

IT is a good ideal to clear security anytime you expereince a problem and try relaod the calibration on a clean slate.

so that seemed to be the problem... car is fine under boost now.

Another weird issue i'm having is while cruising under very light load the car is super rich (10.5-11.5) in all gears. if cruising in 5th gear (i have a 5-speed), if i give it a little more gas it starts to lean out and holds around 12-13.0 and in 4th gear it'll be around 13-14.5. TPS is reading correctly.

My tuner and I went out last night to do some street tuning and try to fix the problem but nothing would change it. He even made some drastic changes to the part throttle tables (took out like 600units of fuel) and still super rich.

Not sure what else the problem could be. A possible ECU problem? Non-ECU related? Any thoughts?

You may be making your changes to the tables for the wrong cam angle.

Spunkster wrote:You may be making your changes to the tables for the wrong cam angle.

the changes were made to each cam angle and no difference.

would it be worth sending you guys the ECU to run a diagnostic check to make sure everything is ok with it? I was also planning on sending it back to get the onboard datalogging added.

You need to post calibrations and datalogs that show the changes and the problem you are experienceing. What you are describing does not sound like a problem with the ecu.

Spunkster wrote:You need to post calibrations and datalogs that show the changes and the problem you are experienceing. What you are describing does not sound like a problem with the ecu.

My initial problem didn't sound like an ecu problem either but erasing the ecu security seemed to do the trick.

I agree that i need to post calibrations and datalogs and i will do so as soon as i can and i really appreciate the help.