06-11-2009, 10:58 AM
Join Date: Jul 2008
Location: Long Beach, CA
Total Cats: 0
99 EMU water temp sensor problems revisited
Well, I just installed an EMU on my 99 using a Boomslang harness and it appears I am having water temp sensor / fan switching problems. I knew of this potential issue before installation from having read pretty much everything I can find on this issue both here and on the new Yahoo E-manage group. After initially installing the EMU, I had no problems with starting, idling, or driving the car. Everything seemed to be operating fine. I don't drive the car daily so I don't have too much time on in yet. Yesterday was the first time I drove it a long distance and I noticed the the coolant temp was creeping up. Since I had read about potential problems with the water temp sensor option, I knew what was up and immediately turned on the AC to force the fans to run. The temp dropped back into the normal range right away. Conclusion - my fans are not switching correctly with the EMU installed.
I would appreciate help from anyone who has successfully gotten the EMU coolant temp option to work properly (especially on a 99). There appears to be a lot of conflicting information around on how to get this to work. I currenlty have JP13 and JP14 set closed (1-2) as instructed in the EMU manual for the air and coolant temp sensor options. I selected the Mazda air and coolant temp sensors which are default when you specify the NB-ZE motor. I have not yet had a chance to try playing with any of these settings. I read on the Yahoo group that someone thinks you need to build an op-amp circuit to isolate the EMU input from the factory ECU and the temp sensor tap-in. Others say they have gotten it to work without that but exact settings are unclear. I also read somewhere that someone had a problem with this in a particular version of the firmware but it was fixed when the firmware was updated. Can someone who has this working please post the following info:
1) JP13 and JP14 settings
2) coolant and air temp sensor selections in paramter setup
3) EMU firmware and support tool version numbers
4) anything special you needed to do to get this to work
I plan to dig deeper into this over the weekend and I will post my findings. Any info that would help me troubleshoot this would be greatly appreciated.