AEM troubles
Hey Folks!
I have a 426 gen3 hemi managed by the MP AEM grey box (part# P5153528). I just crossed about ~3k miles on the brand new motor and it was running GREAT. I was slowly dialing in the calibration but some gremlins began to expose their ugly heads and finally took the system down! Here's the story...
With about 500 miles on the fresh build we were making the 800 mile trek to Mopars at the Strip in Vegas and the car shut down like a switch about a 1/3 of the way into the trip in the middle of the Nevada desert (!!!). We were just cruising along at 75mph (2100rpm), engine temp was 180, and everything seemed normal and fine. We coasted to a stop, checked for the obvious things (leaks, voltage, fuel pressure, etc), and nothing appeared suspect. Turned ignition on, heard the fuel pump activate, and the motor fired right back up, so we went on our way (nervously of course). This happened again another 300 miles down the road and once on the way back. Then it started acting up while driving around town when fully warmed up; engine would start and run for a bit then die. During this bout with car not running and ignition on, I moved my attention under the dash and could hear the main ECM relay in the fuse box clicking on/off rhythmically and the relay felt very warm. I turned ignition off then on again and fired it back up and got me home with no issues.
Last weekend in the middle of a 150 mile mountainous drive to a car show it turns off again. This time I shifted into neutral, turned ignition off then back on, and let the clutch out in 5th to roll start it, hardly breaking my pace (I was getting this down now). It started acting up again driving through the destination town, and finally right before the cruise it "switched off" for the last time and didn't come back. When I turned the ignition on this time, I couldn't hear the fuel pump activate at all. Again, all the usual checks revealed nada. Then I connected a laptop to the ECM and I could tell it was trying but just couldn't establish the connection. Usually when I connect to to the ECM via laptop a progress bar shoots across, the ECM firmware version displays, and the tuning dashboard pops right up. That the fuel pump isn't activating and the ECM isn't staying alive long enough for the laptop to connect, I'm thinking that the ECM went bad. I tried swapping around the relays, unplugging/replugging in the ECM (while power was off of course), and tested the power and grounds of the pin receptacles in the ECM connector (all good there). I even opened up the box to look for fried components or toasty smells. Here is screenshot of the software trying to connect to the ECM...
I was thinking the box may have been overheating since the failure happened after the car has been running awhile, but the installation instructions say to place it in the interior and not be exosed to temps >257F. I have it installed behind the dash secured on top of the bracket above the steering column. There's no way its gets close to that hot in there. Anybody have any ideas? I wish I had another unit to test with. Along those lines, I'd be very interested in picking up another MP AEM box (P5153528) if anyone has one laying around they're not using. It looks like this...
Otherwise I'm afraid my only other option is to consider going a whole other EFI route: factory DBW, FAST/XFI, etc.
Hey Folks!
I have a 426 gen3 hemi managed by the MP AEM grey box (part# P5153528). I just crossed about ~3k miles on the brand new motor and it was running GREAT. I was slowly dialing in the calibration but some gremlins began to expose their ugly heads and finally took the system down! Here's the story...
With about 500 miles on the fresh build we were making the 800 mile trek to Mopars at the Strip in Vegas and the car shut down like a switch about a 1/3 of the way into the trip in the middle of the Nevada desert (!!!). We were just cruising along at 75mph (2100rpm), engine temp was 180, and everything seemed normal and fine. We coasted to a stop, checked for the obvious things (leaks, voltage, fuel pressure, etc), and nothing appeared suspect. Turned ignition on, heard the fuel pump activate, and the motor fired right back up, so we went on our way (nervously of course). This happened again another 300 miles down the road and once on the way back. Then it started acting up while driving around town when fully warmed up; engine would start and run for a bit then die. During this bout with car not running and ignition on, I moved my attention under the dash and could hear the main ECM relay in the fuse box clicking on/off rhythmically and the relay felt very warm. I turned ignition off then on again and fired it back up and got me home with no issues.
Last weekend in the middle of a 150 mile mountainous drive to a car show it turns off again. This time I shifted into neutral, turned ignition off then back on, and let the clutch out in 5th to roll start it, hardly breaking my pace (I was getting this down now). It started acting up again driving through the destination town, and finally right before the cruise it "switched off" for the last time and didn't come back. When I turned the ignition on this time, I couldn't hear the fuel pump activate at all. Again, all the usual checks revealed nada. Then I connected a laptop to the ECM and I could tell it was trying but just couldn't establish the connection. Usually when I connect to to the ECM via laptop a progress bar shoots across, the ECM firmware version displays, and the tuning dashboard pops right up. That the fuel pump isn't activating and the ECM isn't staying alive long enough for the laptop to connect, I'm thinking that the ECM went bad. I tried swapping around the relays, unplugging/replugging in the ECM (while power was off of course), and tested the power and grounds of the pin receptacles in the ECM connector (all good there). I even opened up the box to look for fried components or toasty smells. Here is screenshot of the software trying to connect to the ECM...
I was thinking the box may have been overheating since the failure happened after the car has been running awhile, but the installation instructions say to place it in the interior and not be exosed to temps >257F. I have it installed behind the dash secured on top of the bracket above the steering column. There's no way its gets close to that hot in there. Anybody have any ideas? I wish I had another unit to test with. Along those lines, I'd be very interested in picking up another MP AEM box (P5153528) if anyone has one laying around they're not using. It looks like this...
Otherwise I'm afraid my only other option is to consider going a whole other EFI route: factory DBW, FAST/XFI, etc.
