Hey guys,

I've been having a problem getting the EGT's to properly work. I've got an AEM originally designed for an S2000 (p/n 30-1052). I've gone through the set up on the computer. The wire's are connected to the right pin and a solid ground.

But the damn thing still won't work. it's driving me bonkers.

I was hoping if any other team out there is using the AEM EMS with EGT's has some suggestions as to where I'm going wrong.

thanks

What "doesn't work" about it?

FWIW EGT readings don't mean too too much. Generally a change in EGT is what you want to note. And I wouldnt have that as a closed loop system of any sort on the motor...

I'm not sure if the AEM EMS has an amplifier built into it or not. If the site or manual does not mention that it does, then you need a separate amplifier box. We run MoTec with 4 EGTs with a custom amplifier made by our EE. We also have an AEM brand amplifier that you may want to look into.

Doesn't Work: there is no signal coming out of the AEM. I don't run a closed loop system. I have the EGT fuel correction checked, but the system has a fuel multiplier of zero.

The AEM does not have an amplifier. It's not like a thermocouple. It's an RTD-type EGT, AEM brand.

I still have a feeling I'm missing something within the AEM itself. whether it's some sort of box to check, uncheck or anything. It's gonna end up being some small, miniscule step to make me feel like a doofus.

Side Note: i've actually gotten the system to work before in the past. I ran a 5V source through a 400 ohm resistor. Following the resistor is a three-wire node. One from the 5V source, one sent to the AEM pin, and the last wire goes to the sensor. The other wire on the EGT is attached to a ground.

This set up worked. However, it limited the voltage range and resolution was terrible. Instead of 12 (i think) points to calibrate the sensor, I only had 6.


I hope this is all clear. I'm just hoping someone here has used the AEM with RTD-type EGT's with success.

AEM has great technical support - open 9-5, Mon-Fri - give them a call. 310-484-2322 extension 2

Goodluck.

Exactly! AEM would be happy to help!

quote:

Originally posted by The Gus:
AEM has great technical support - open 9-5, Mon-Fri - give them a call. 310-484-2322 extension 2

Goodluck.

Note to self. When in doubt, call the creator.

I just had a duh! moment...


thanks guys haha

Figured it out. The AEM unit was actually bad. While trouble shooting during the week, we swapped one AEM for another that we have as a backup.

IT WORKED!

I think the original unit shorted at some point. But we've had it for 2 years and never used the EGT function. So I'm unsure of what/when this all happened.

But if anyone choses to use RTD EGT's with the AEM ECU, here are the steps...

Gray = Ground
White = Signal to AEM

Go to the EGT Wizard in AEM and assign the proper Sensor (in my case is was AEM: ALL OTHER EGT APPLICATIONS) This also turns on EGT Fuel correction, which must be turned on. If you're not using EGT's for fuel, then just set the correction factor to zero.

If you're only using one EGT, you must disable all the other sensors (this can be done under the EGT Options window)

Then...measure hot things!

i doubt your aem was bad. your egt inputs were probably setup for either a 0-5v input or a thermistor input. It sounds strange but the AEM can be setup in one of three ways via internal jumpers: RTD EGT, 0-5V, Thermistor. each setting has different pull up/down resistors. Your RTD's would not work if you were on one of the other settings.

For future reference, which option menu gives you the ability to change the EGT input? i looked and looked (at least i'd like to think so) and i still came up with nada

it's an internal jumper setting. hardware, not software. Whoever sold you the aem should be able to adjust those settings for you.

Most AEM EMS's have an internal pull-up resistor on the EGT channel, and on some of the newer EMS's a jumper on the PCB can be moved to switch between different values of pull up resistors.

In my freshman circuits lab, we were taught how to find the value of an unknown pull-up resistor. Add another known-value resistor connecting to ground, measure the voltage at the junction, and you should be able to calculate the unknown resistor from that as long as you know that the power supply to the pullup resistor is 5V.

For all those reading this, AEM DOES make an amplifier for K-type thermocouples.