Nistune Forums

First off i have an s13 with a ca18det with the type one board. it has a nismo FPR and a walbro 255 in tank. 800 cc injectors and a z32 MAF. i have been trying to figure out why everyone elses K constant is way lower than mine and why i run super lean if im at that number. i Have my car set now at 355 K constant. by the numbers it should be somewhere near 250-260ish. i dont have access to my fuel pressure gauge at the moment but the pump is about 6-7 years old. i am running lean all throughout the map when i try and run the similar maps from other cars tweaked to my modifications. maybe someone has seen this happen before?

Sounds like fuel pump. You really need to borrow a fuel pressure gauge (or replace the fuel pump assuming it is this)

yeah i just moved and dont have all my tools available right at the moment. im thinking this could be my issue. Anyone ever had a walbro go bad after a few years. i read a bunch of stuff online bashing the walbros but mine has worked for awhile.

Ok update on this. I have verified that i do have a 35F11 ECU (CA18DE) running a DET... shouldnt be an issue but i have read online that the different base images can be mixed up and cause a problem. I was running the car today and i have a very rich idle (10's) and no matter how low i set my K constant it wont affect my idle AFR reading. The car still idles rich and drives lean. So its definatley not a vacuum leak. im wondering if i dont have some ECU problems? Mayeb i should send the board in for a new base image? the title bar on my laptop says 23710-35F11 REV:15 (U). up top it says [s13/rs13/U12 (CA18DET)]. Matt do you think there could be an issue there. i have spare ECUs i can try if need be. Just have to send them off to be resoldered in another board.

You are using a CA18DE ECU with matching base image

You will require the ECU to be reflashed with a CA18DET ECU image (36F05) and it will be compatible with the CA18DE ECU.

Yes you are correct in that there are some ECU/hardware which cannot be mixed but using turbo program on a NA computer will work fine

So if im understanding this correctly i need to fix this as it is a problem? I have extra CA18DET ECUs i can send off to have the daughterboard soldered into those if that will be better. Could this be causing me not to be able to ever get the car running like i want to? its never been 100% and ive always had issues with it. Thanks for the help!

Not knowing the mechanical state of the rest of your car does not help things here, and using a NA ECU+program for a turbo application is also another problem

Use either ECU. If you have a turbo one there then use this instead with the matching base image. Once you have sorted that, adjusted the settings and checked your fuel pressure we can then work from here.

I'm not going to try and guess if it will fix the problem due to too many variables

Right i totally agree with you there. I am going to try and dig out my fuel pressure gauge this weekend to check that out. I am just curious as to what kinds of problem can be created by having the base image mixed up on my ecu? I do understand that everything else on my car needs to be in working order before assuming any ECU issues. i have checked over everything except the fuel pump. I am planning on changing the fuel filter and checking fuel pressure this weekend.