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View Full Version : AEM EMS Connects but all values go everywhere


j87w
02-28-2009, 07:42 AM
Ive got the AEM EMS to connect using a IOGear USB to Serial adapter. The TPS Voltage stays at 2.4-2.5volts with just the ignition on (even at closed throttle and WOT, and with the TPS plug disconnected). It shows 2.2 volts even though I checked the incoming power and its 12.2 volts (I even put a battery charger on to make sure the battery had plenty of juice). It shows the A/F is 4.5:1 with the WB02 unplugged (external AEM WB02 Gauge). It says there is engine load, map pressure, ect (with the engine just in the on position). I have reinstalled the software, reinstalled the USB to Serial adapter software, Checked to make sure the ECU plug was plugged into the EMS all the way, ect. I know this harness used to run a stock ECU just fine. Any ideas? This is on a SR20DET by the way but it almost seems like a software issue or something.
Thanks guys

j87w
02-28-2009, 05:04 PM
I started the car and it idles somewhat ok. I put a meter on the plug comming right off the TPS and it shows .45V at closed throttle and 4V at WOT. The AEM still shows 2.4-2.7V for TPS regardless of throttle position. The EMS is setup for gasoline and still shows the car is idling at 4.5:1 and the AEM UEGO Gauge shows the car idling between 11-14:1. (Probably because the throttle isnt set right so it bounces back and forth between WOT and closed throttle). It also shows it has engine load still with just the key on.
Any other thoughts?

j87w
03-01-2009, 11:17 AM
I got another serial to usb adapter and tried it. Now the TPS voltage reads 4.3-4.6V regardless of throttle position. Coolant temp with the car off reads 45F and IAT reads 55F (which sounds about right, the car hasent been started). Vehicle speed shows 0MPH which is right. Ignition timing is 10 degrees with the key in the on position. Fuel Injector #1 pulse with the ignition in the on position is 9475-9495(moves back and forth rapidly). 02 #1 AFR is 4.45:1 (set on gasoline). Engine load is 93.24 KPA regardless of if the car is on or off. I even tried to reload a new map with the new USB cable.

j87w
03-01-2009, 11:21 PM
Finally after going through manuals and doing some thinking I figured it out. Pin 19 Output from UEGO WB02 (stock NB02 input) and Pin 20 (TPS) are right next to each other. They use the same color of wire. Somehow I mixed up the wires. I cut the TPS wire so it was no longer connected and soldered the Output from the UEGO WB02 into pin 20. Thats why the TPS was reading the weird voltages. I no longer had an 02 sensor so pin 19 would just read 0 volts (10.00 A/F Ratio). I swapped thie wires and it works fine. Now I just got to find out why it idles at 10.5:1.