Have a 2019 connect and cruise LT4 8L90 crate package in my 66 C10. Using the ECU fan control to turn on/off my two cooling fans. They presently turn on at 207 and 227F. Seems high and would like to lower a bit. I see the tables under system, but can't get my head around where to adjust?
Cgt-work.hpt
Are they discrete on/off type fans? I'm not sure that a GEN 5 controller can do discrete fans even though the tab is there. Yours is set to PWM which is a variable speed type fan.Originally Posted by vet57air
Beyond that.. these two tables in this image control your fan turn on/off points. You can see when it goes 0-1, 1-2, 2-1, 1-0
fan.PNG
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They are discrete on/off. It turns on one fan at 207F and the other at 227F. This info is in the GM literature and I can confirm in the real world. I know GM does the crate programming a little different from oem. I just don't see why to let the engine temp. go that high. Would like to lower the on temperatures to about 205 and 210 respectively. I see your table on the left, and can't seem to change variables, but can't find the other on the right.
Those two tables should be all you need.. Tell me what turn on and off point your roughly looking for and I'll just do it.
Our company made this video. It should explain how the two tables I showed you work. To be perfectly honest I haven't watched it all but I'm sure its correct. We do a lot of Efan conversions
https://youtu.be/862kJez6su4?t=297
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So I assume the tables you were looking at are not from my file as while I do have control by desired %(under control by %). My desired ECT (under control by ECT) heading is just that and not current state. If you open my desired ECT it looks very different. I want to lower the fans on transition to 205 and 210.
The tables are there.. just scroll down. if you compare differences you'll see how I did it.
Cgt-work (1). fans.hpt
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Thank you so much. I did a compare and saw the changes to ECM 18060. Looks straight forward. But I must be missing something as I still cannot find the other table you mentioned ECM 18040. Watching the video they click on two tables ECM 18060 which I have, but the other table they click on is the top table ECM 18040 (state vs desired %) which in my file is ECM 18170 (Desired ECT). What am I missing?
Last edited by vet57air; 09-21-2023 at 01:04 PM.
Here.. does this help?
Capture.PNG
The circled thing.. That's an odd one. In GEN 4 that should be set to discrete for a on/off type operation. I have no idea why yours was and is set to PWM electric. It must have something to do with the GMPP stuff. Thats why I asked if they are on/off type fans
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Thx again. LT4 is Gen V. I will try to make changes to ECM 18060 to see if it make a difference. I'm sure that there are a lot of guys with crate engines that want to do the same.
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