Extreme loss of performance and fuel economy

zach_04lx · Post by **zach_04lx** » Mon Dec 07, 2009 1:02 pm

Hello,

Firstly, here is a summary of my car specs and such:

KManager Version: 1.3.9
Vehicle: 2004 USDM Honda Civic LX coupe with JDM K20a (ITR) swap (Y2M3 tranny) - custom CAI and exhaust
ECU: PND with K-pro

I have had this same setup for a couple years now. Last year around this time I had the same problem, but it was not this severe. When it gets cold outside, my fuel economy and performance both drop drastically. For instance, it is between approximately 0 and 5 degrees Celsius here, and the colder it gets, the worse the problem gets.

During the hot summer months (~25 - 38 Celsius), I get around 550 - 575 km to the tank (~47 litres). On my tank last week, I only got 420 km. It also seems very sluggish.

I have attached my .kal, and will go out and datalog if that will help in analysing the problem.

Thank you preemptively,
Zach

kb58 · Post by **kb58** » Mon Dec 07, 2009 1:05 pm

I know of OEM cars where the same thing happens. It may have nothing to do with KPro.

zach_04lx · Post by **zach_04lx** » Mon Dec 07, 2009 1:08 pm

It just seems so odd because of how extreme it is. I could possibly see a slight drop in fuel economy, but this is insane! Is there anything for which I should look to diagnose the problem?

Thank you for your prompt reply though. :)

zach_04lx · Post by **zach_04lx** » Sun Dec 13, 2009 10:59 pm

I went out for a typical drive today and did some datalogging (for quite some time). I have uploaded the log to my server as it kept getting an upload error here. Can anyone offer me some ideas on troubleshooting? There is obviously a problem with the AF as it is quite erratic.

Datalog (~5 degrees C outside)

Post by **Hondata** » Mon Dec 14, 2009 11:21 am

In your datalog the short term fuel trim is maxed out (+47%). Look at the oxygen sensor first.

zach_04lx · Post by **zach_04lx** » Thu Dec 17, 2009 11:38 am

I have changed out the primary O2 and now the problems seemed to have gone away. It doesn't feel like I'm going to buck through the dashboard when I shift, and the performance is back. I haven't gone through a tank of gas to see whether or not the fuel economy is back to normal. I also haven't datalogged yet (need to borrow a friend's laptop with Windows since KManager doesn't work nicely with Linux), but it seems good.

Though the performance and such seems to be back to normal, I am now throwing two CELs. I get codes P0134 and P1166 regarding the primary O2. I have cleared them, but they come back after the car has been on for a few seconds. Any ideas?

Thank you very much for the help thus far.
--Zach

The Spectacle · Post by **The Spectacle** » Thu Dec 17, 2009 2:16 pm

Those codes typically mean the o2 is wired in wrong. Did you install a PnP o2 or splice a non standard one into your existing wiring?

I bet if you check your datalog now, you're running in open loop which is why the car is running better.

zach_04lx · Post by **zach_04lx** » Thu Dec 17, 2009 2:26 pm

It is a PnP one, and I don't know why I wouldn't have the CELs on the previous one but I do on this one. This O2 is the Denso 234-9005 which is for the RSX type-S. Is it bad to be running open loop? Sorry for the dumb questions, but this is not really my area of expertise. I will datalog sometime soon.