The aem ems has recognise the oem ECT inputs.
I've enquired about this with aem before. Their reponse was that the ecu has an output wich produce different frequency to the oem ecu and is not recognised by the dash. I asked about a relay or some sort of microcontroller and they gave me the impression that they have other priorities atm and not just our small glitches.

It doesn't bother me much because I got an external temp gauge and setted the ems to throw a CEL when ECT get too hot.

modifry, this sounds like a perfect challenge for ya...I hope you can solve it

 

I've done the same, but it sure would be nice to have the OEM temp gauge back so that I can see the 3 bars and know it's OK to engage VTEC.

 

What temp did you set the CEL alarm too BTW?

 

Mine is set at 215 degrees F.

 

Cheers! That's just over 100 degrees Celcius.

 

The only insight I have is concerning the input calibration table. Which was in this link.
http://forums.s2ki.com/forums/index.php?showtopic=184552

The only piece I know concerning the output of the AEM concerning the coolant gauge is just what Aus said in that the AEM supposedly can't drive the signal needed for the coolant gauge.

You can take all the necessary measurements at the ECM itself. No need to take apart the dash. Just need a DVM, Scope, wire and taps. Here's an overall picture of the circuit.


Measure the ECT input to the ECM with the DVM across pins C26 and C18 on the ECM.


Then measure the ECT output to the dash with the scope across pin A1 and chassis ground (or may have to pull a ground off the ECM).


Just make sure to take a reading right after starting with the engine cold, a few as the engine warms up and then once it's warm. It would be nice to get screen dumps from the scope. I don't have a scope to try this... Although, I'm going to ask around some friends, or maybe finally use this as an excuse to get one of the laptop scopes.

 

My choice:
Pico ADC-212/100

And it's on sale. I like their new USB-powered scopes but till they have one that's as good or better than what I've got I'll wait.

 

Hi Modifry,

Are you interested in this project? I confess that you and MacGyver were the first to come to mind when I started this.

From a commercial point of view this product has very little scope. I expect the number of S2000 owners with AEM EMS would be numbered in the 10s rather than the 1000s. But then my very limited understanding of the issue leads me to believe it is fairly simple to solve.

 

200 MHz DSO myself... it ain't portable, but it has helped me hunt down more than one fast-acting glitch in a system. I swear the thing runs Windows as it takes a good 10-15 minutes before it claims calibration is complete (heating up), but I rarely need that kind of calibration for my work. Expensive, but indespensible

Aus, I guess I fail to understan what the issue is. The sensor is obviously a resistive element (as expected), so it seems hard to believe that Honda would go to a lot of toruble encoding the data into a digital communication signal before transferring it to the dash. Does AEM provide any useful info other than "It doesn't work with a stock system"?

 

Not to get on a tangent, but here's an alternative to the Pico scopes...

http://www.usb-instruments.com/