AEM Ultimate Resource Thread>>>>

[AlmosN8kd]

COM2 is the serial port as it is the only one available under ports that is eligible. COM3 and COM4 are listed as bluetooth interfaces and LPT1 is the printer port. I'll take a look under modems to see what I can figure out but I don't think I know my way around what you're saying too much.

Edit:

I disabled the stuff in device manger listed under modems. I didn't see any sort of faxing software and I don't believe my computer has any installed. I've had the computer since it was new but it did come with a lot of software so it is possible to have it and not know it although I've never used it. I still cannot get it to connect; it says "Failure to connect to ECU" in the error that pops up within seconds.

[AlmosN8kd]

Updates (I posted this on AEM's forum in the 1311 category to see if I could get help there as well):

I've had my EMS for about a year but I just installed it this past week. I bought it awhile ago and before I could install it I spun a bearing and took the car down for rebuild/build up. Once I got the engine work completed, I did my engine break in on the stock fuel system and stock ECU to prevent any problems associated with an engine break in on a bad tune. Anyhow, I get everything in and ready to go, hook up my laptop and I have no luck connecting. I've tried everything I could think of to get it to connect as well as suggestions on here as well as other forums and have had no luck. Now, I think my EMS is bad and here's why. I go to a cjbyron's house yesterday and see if he can connect to my EMS; nope, doesn't connect. Then I try to connect my laptop to his EMS; we had to cycle the key from On to Off to On but the damn thing connected on the first try through the built in serial port on my laptop. So, if my computer can connect to another EMS just fine but not mine and another computer besides mine cannot connect to my EMS then the problem is obviously with my EMS which really ticks me off since the damn thing is not cheap and now doesn't work. So, either my EMS is bad or it isn't setup properly. I've read through and tried everything I could find in the "getting started" portion of the user's guide to AEMPro but I do want to rule out having a faulty unit. Can someone here provide some further insight on what I may be doing wrong or confirm that my EMS is actaully faulty?

[cjbyron]

Yeah the AEM Forum > 3000GT section is pretty sparse on replies or help that's for sure. Few visitors there it would seem.

My previous A/C question (if nothing else then a reference for others?).

After installing AEM EMS my a/c stopped working. I don't have a complete fix figured out yet but hopefully will shortly. Currently all I know is that the AEM is not engaging the AC compressor's magnetic clutch. Everything else appears to be working fine (blower, condensor fan goes to hi, no flashing a/c light, etc. that would indicate any module failure).

AEM uses:
switch #3 for A/C on request; default is sw3/off=ground
LS #6 for A/C compressor magnetic clutch relay

LS #6 is active the entire time the engine is running (when shown in parameters window). A/C on/off does not change the parameter in AEM EMS.

Under OEM ECU pin 22 is magnetic clutch relay, pin 45 is magnetic clutch itself. This matches the AEM pinout config properly.

Pin 22 should go to B+ on call for A/C or at least 6 v momentarily (per OEM specs). Pin 45 should go to B+ when A/C on and 0-3v when A/C off.

The AEM is not showing B+ at either pin on A/C call. Everything else works. If I jump the A/C magnetic clutch relay under the hood the clutch engages (hear the 'click) - manual page 298 shows pinout on relay (pin 4 is B+ from ded. fuse #9 and pin 5 is + to clutch, pins 1 & 3 are the relay coil)

At this point it seems in the 1311 box and not the car. Everything else checks out fine but the AEM isn't giving B+ as it should at the pins (22 & 45).

[AlmosN8kd]

Craig,

My A/C works perfectly on the AEM; the problem must be something with your car. I'd recommend hooking up some guages to your A/C system to see if you need a recharge.

[cjbyron]

Not necessarily. A/C worked fine before AEM.

Just like why you couldn't get your car started with AEM - there was something wrong inside your unit.

SW#3 is not coming to ground like it should, LS6 does not change state.

Fricking A/C system......the damned schematic on this thing is uber complicated (considering what it is)

I will check some other voltage readings tomorrow and see if I can narrow down what's going on.

Also - even with magnetic clutch relay jumpered on there is no cold air.

[AlmosN8kd]

Originally Posted by cjbyron

Just like why you couldn't get your car started with AEM - there was something wrong inside your unit.

Not related at all. I never attempted to start the car on the AEM because there was nothing programmed into it since I could never get an inital communication to load a map into it to attempt to start the car. Anyhow, don't take the fact that A/C worked fine before AEM as that is the source of the problem. You stated yourself that you are running the A/C system for the first time since last summer and it didn't work; this is very common on a lot of cars and automotive repair places love A/C season (I used to see it every year when I was in FL). Basically, at the beginning of the summer, lots of people have A/C system problems because they are starting their perfectly working systems (or at least they were the last time they used them) for the first time and they don't work. So, I'm not saying that it is or is not the AEM EMS; I'm saying don't rule it out as the sole possibility. If you absolutely want to rule it out, unplug your EMS, plug in your stock ECU, turn the key on, and turn the A/C on; if the magnetic clutch kicks over then I'd say yeah, it's possibly a problem with the EMS; if it doesn't then there's a good chance that the problem is with the A/C system itself; if you could run the engine on the stock ECU (although very unlikely considering you're speed density and all the other mods you've got, you'd basically run really rich in safe mode if you could get it running at all) and verify that the A/C system blows cold air then you'd know for sure it's the EMS.

[cjbyron]

Considered swapping with oem ecu to check yeah. We'll see.

The A/C has worked fine since 1995 so I look at the common factor of what has changed. The answer is the ECU -> AEM. Could it be something else unlrealted? Sure it could but I first look at probables based on changes made rather than coincidence. Coupled with bad readings from the AEM lends credibility to the probability that the problem is within there.

[AlmosN8kd]

A/C systems go bad or leak over time; it's a fact of life. Or, while you had all your work being done on your car over the last year something could have damaged the A/C system. Or a rock chipped your A/C condenser causing your system to fail. Either put the stock ECU in and see if you can get it to work or back track the problem; since the EMS is not outputting the right signal then check the inputs to the EMS for the A/C. Namely, jump the pressure switch and see if it works. My A/C fired up just fine with the EMS so I doubt that is your problem unless there is just a random quirk in your EMS.

[cjbyron]

Or aliens landing in the back yard.

Phhhttttt..

I have checked / tested the basics 9such as refridgerant, etc. Troubleshooting by going after things that would be a 'coincidence' rather than what has changed isn't the best way IMHO. IOT - I doubt the coincidence that something in my A/C decided to fail when I put in the AEM. Maybe. But odds/avgs usually don't point to the coincidental things but what changed.

Only thing left to check is the pressure switch and actual AC controller.

I have thought of swapping the ECU but I cannot run the car with the OEM ECU. I might put pin 22 to gnd and pin 45 to b+ and see but have to check that doing so wouldn't cause other problems first.

[AlmosN8kd]

Originally Posted by cjbyron

Or aliens landing in the back yard.

Phhhttttt..

I have checked / tested the basics 9such as refridgerant, etc. Troubleshooting by going after things that would be a 'coincidence' rather than what has changed isn't the best way IMHO. IOT - I doubt the coincidence that something in my A/C decided to fail when I put in the AEM. Maybe. But odds/avgs usually don't point to the coincidental things but what changed.

Only thing left to check is the pressure switch and actual AC controller.

I have thought of swapping the ECU but I cannot run the car with the OEM ECU. I might put pin 22 to gnd and pin 45 to b+ and see but have to check that doing so wouldn't cause other problems first.

You said that you hadn't run the A/C since last summer, correct? That means throughout the winter something may have happend that has caused your A/C to fail. Or, it may have even been programmed out by Dyno Authority. If you plug in the stock ECU, no your car won't run but turn the key to ON and try to start the A/C to see if the clutch picks up; that was my earlier suggestion.