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I actually have TunerCat for my tuning software. I've just been using HP Tuners and EFI Live to look at other factory vehicle tunes to see how the vehicles I want to replicate are tuned.
As for the EGR, just to clarify, I still hooked up the A/C pressure sensor wire (the one who's voltage varies) to the correct pin in the PCM. The same pin it connects to on the Camaros. I only used the EGR pins for my +5V and 0V reference wires cause I wasn't using the EGR anymore and I didn't want to have to splice into any wiring to get my +5V and 0V references in case this science experiment didn't work.
As for logging the signal, I use the good old AutoTap software which doesn't have much capability, but what I do know is before the programming it would list the A/C pressure as an option but it would always read 0V. After the updated programming it would read a voltage number for the A/C pressure, but without a scale to know what 0 and 5V correspond to it doesn't do me much good.
Just out of curiosity I just pulled up a truck in EFI Live (1999 GMC Sierra 5.3). Looks like it does have all the settings needed. Even AC pressure for fan #2 and can switch the recirc output for fan 2 control, etc. Below shows all the relevant segment screens for fans and AC. The EGR one is part that I'm not yet sure about. I need to dig some more... Under Engine Cal EGR does give you the options, enable or disable. Som I'm guessing I can just disable it there, remove the hardware and block its ports off.
I have a custom tune through Black Bear Performance and inquired about adding e-fans to my 01 when we were first getting logs for the tune. He said my OS should support e-fans, see quote here:
The current OS *should* support electric fans without any problem. My own 2001 8.1L suburban is running electric fans on the factory OS. In order for your fans to operate like a 2005+ model though, you will have to remove the red pin 33 Auto HVAC Recirculate wiring and install the fan wiring. Not a problem to do so, most customers that have done that have lost no functionality. I have my 2001 set up that way. - Justin at BBP
I suppose the fans will work fine this way, but it won't be activated based on pressure and only rather when A/C is on/off, so the sensor should allow finer control over the operation of the fans.
Edit: Also some user had his tune modified by another user or mod over on EFILive to include the sensor activation, so I suppose if we ask nicely over there we can get it as well. https://forum.efilive.com/showthread...ling-fan-issue
Last edited by silentbravo; 08-14-2018 at 04:27 PM.
Nice find at EFI! I went ahead and ordered the trinary pressure switch and harness from BP Automotive today. Hopefully I'll have time to dig into this some in the next month while I have a ton of other things pulled apart on the truck.
Here are some screen shots from HPTuners software showing the setting that needs changed to convert the 1999-2002 trucks from using a high pressure switch to a high pressure sensor. One screenshot is from a mostly stock 2002 6.0, the other is from a 2002 Camaro (which use a pressure sensor)
Truck
Camaro
As was stated in the EFI Live thread you guys posted, this setting is not mapped out in EFI Live. It is mapped in TunerCats and HP Tuners.
I appreciate the scaling info for the A/C high pressure sensor. In case the link breaks in the future, I'm posting a quote from that thread here.
After re-investigating, I think this is what the AC pressure should be:
psi = V*94.0479-18.8721
kPa = V*648.4372-130.1184
The psi range is: 0 to about 450kPa
The kPa range is: 0 to about 3000kPa
A minimum of zero is forced by the PCM, even though mathematically it can be negative.
Note: The conversion from V to psi is done via a lookup table in the PCM. The above information is based on me looking at only one vehicle. That means it may not be accurate for every LS1 calibration.
Here is a bit more info from the GM eSI system (same system you have docs in the first post from with the schematics)..This describes the functionality of the system with the conditions (pressures and temps) at which single or both fans are activated.
Edit to add - I'm also going to upgrade the entire OS on my 99. Based on what I've read here https://www.performancetrucks.net/fo...h-info-536648/ and in a couple of other threads it seems to be the general consensus that the original 1999-2000 OS is pretty inferior overall to the 2002 OS in a number of ways and its hit and miss on whether people have been able to get the fans working the way they want to on the original OS. One I still need to verify is I read on some other thread somewhere (hard to keep track of all of them) that the 2002 trucks did use different injectors though and that might cause running issues. Before I flash my ECM I'm going to dig a bit more on doing a full flash of a 2002 OS on an earlier truck ECM.
One thing that would be a big help to every 99-01 truck owner is if there is one definitive resource that is the best how to for this along with a couple of notes for 02 owners and then another for 2003+ owners wanting to do this. I have seen that you did mention this in a few other sites as well which is a good thing. I think once I also get some things figured out on mine as well as what you figure out I think you should edit the original post with more info as far as part numbers, specific fans to get (7/9 blade), OEM harness info, and tune info. You already have a lot there which is great.
Not really on my end.... Rather than flash my 99 EMC with a 2002 OS I did pick up a 2002 411 ECM though. That way if I do have any sort of issues I can simply swap the entire ecm back in. But I've not had time to install the trinary pressure switch or anything else yet. I did make a bench harness for the 411 though so I could check it over with my Tech 2 and TIS200 to make sure everything is updated and current in it. Then using the same harness connected it to the EFI Live and did a calibration dump so I can start on poking around in it, change the VIN, etc.
I'd love to hear from the OP or anyone else who has done this swap to see if there are any updates. I did the efan swap on my 2000 LS swapped OBS Silverado using a 02 harness and ECU. This is what I've been looking for as a way to control both the fans with engine temp and A/C status.
I'd love to hear from the OP or anyone else who has done this swap to see if there are any updates. I did the efan swap on my 2000 LS swapped OBS Silverado using a 02 harness and ECU. This is what I've been looking for as a way to control both the fans with engine temp and A/C status.
Short version: Its working fantastic, just as expected, I have no complaints.
Long version: The fan control works exactly as expected. It runs the fans on low whenever they are needed. Often when the A/C is first started on a cooler day it will be 15-30 seconds before the fans start running on low since the high side pressure needs to build up first before it sees a need to begin running the fans. Depending on the day and operating conditions the fans will either run continuously on low or cycle on and off as needed just as one would expect with a factory setup. Really the only complaint I have is that I set the turn on and off set points for the high speed fans a little too low. The factory setpoint in the 06+ trucks was just too darn high for me, often swinging the engine temp needle quite a way above operating temp (still in the safe zone) before finally commanding the fans on high. I have been in a few other trucks on the ranch that have slightly plugged radiators and you can see the swing on the gauge as the temp rises before the high speed finally kicks in and drops it down. So, as probably noted in my original post, I set the high speed setpoints quite a bit lower. I think I set them a little too low as when they do come on while puttering around the ranch you just about have to stop the truck to get enough engine load off it for the fans to bring the temp down below the shutoff point. I plan to raise the high speed on and off settings 1-2 *C, I just haven't made the time for it. Of course this isn't at all a fault of the setup, just my tweaks on the fan settings. The setup is by far the best thing I have done, it is so nice to get it and have almost instantly cold A/C blowing out of the vents even while stopped. I remember before this sitting in traffic on a hot day and feeling the vents start to blow warm humid air due to the lack of low speed air flow from the clutch fan...no more!!! With the electric fans it is always blowing cold A/C. It also helps when you have the A/C running while stopped to keep the engine temps from rising on a really hot day.
Hope this helps. This setup using the actual high side pressure sensor for the A/C is the only way to do an electric fan swap!! It works prefect, don't even think about it any more, just like factory.
08-14-2018, 01:59 PM
Below shows all the relevant segment screens for fans and AC. The EGR one is part that I'm not yet sure about. I need to dig some more... Under Engine Cal EGR does give you the options, enable or disable. Som I'm guessing I can just disable it there, remove the hardware and block its ports off.
