What controls fan / light load

[paulsvang]

I'm working on a ka24de with a turbo set. Z32 maf with 600cc injectors. O2 disabled and Knock disabled because they are disconnected. I have k constant dialed in with regards to air/fuel but when the fan kicks on, the air fuel goes down to the 10s. Is there a map that controls the load. I can't seem to find it. I'm on a usdm s13 ka24de part 54F00. Battery at 13.5v (looking to get a new battery since it's showing signs of weakness). Any help would be appreciated.

[Matt]

Most problems like this are not ECU related but bad grounding in the vehicle

If you watch when the fans kick in, and take a log (stream mode) of the problem. Watch the battery (at ECU), RPM, MAF and injection time.

You shouldnt see any of these drop when the fans kick in. If only the AFRs drop but injection time is the same then there may be a grounding issue from the ECU/injectors

[paulsvang]

Matt,

Thanks. I'll monitor that. I have another question. Is it possible to change when the fan turns on based on temperature? The reason I ask is because this car that I'm working on has a manual switch. I'm monitoring the temp and turning it on at 80C and turning it back off at 70c.

I'm also trying to switch off the knock and stock o2 sensor. I've changed the flag and unchecked "knock analysis" and "o2 sensor analysis". I thought that was the process. It seemed to work fine but today while doing some more logging, I received a DTC for o2 and knock. Kind of odd to me. Is there something I'm missing?

thanks again Matt.

Paul

[Matt]

Most ECUs have hard coded fan control output. Feature Pack allows adjustment of the temperatures by updating the fan control code

viewtopic.php?f=12&t=2874

If your vehicle is listed here then it can be updated to use Feature Pack (uploaded on all new boards)

If you disable the knock analysis and O2 feedback, it doesnt turn off fault codes. If you have 'DTC filters' available (displays in User Mode : Expert) then you can clear fault codes too