My MKIV non-turbo Supra, a car I’ve cherished for five years, recently presented a perplexing problem: an ECU failure. About five years ago, the engine abruptly shut off while driving, and extensive troubleshooting pointed to a faulty ECU. Despite the handwritten “W57” in the image below (my car is actually a W58 5-speed), the ECU issue was undeniable.
Currently, to keep my Supra running, I’ve installed an AEM v2 standalone ECU. This aftermarket solution has allowed me to continue driving and enjoy my vehicle, but it hasn’t been without its own set of challenges.
In an attempt to rectify the original issue, I sent the factory ECU for repair to a company found on eBay shortly after the initial failure. Unfortunately, even after their repair attempts, the original ECU still fails to crank the engine. This has left me in a position where I’m seeking recommendations for a reputable company specializing in 2JZGE or 2JZGTE ECU repair. Finding reliable repair services for these ECUs, especially for used cars, is crucial for enthusiasts like myself who want to maintain the originality and reliability of their vehicles.
Adding to the complexity, I possess two spare 2JZGE ECUs. These units do crank the engine, which is a step in the right direction. However, the engine runs poorly with these spare ECUs, exhibiting symptoms similar to a disconnected MAF sensor. The performance is significantly degraded, and the engine stalls without constant throttle input. This behavior is not ideal, and points to potential incompatibility or issues even with these spare units.
While the AEM standalone ECU allows the car to run, it’s not without its quirks. One persistent issue is that if the car sits for an extended period while connected to a battery tender, the AEM ECU sometimes refuses to crank the engine. In these situations, it often feels like a timing issue during cranking. My usual workaround involves connecting a laptop, re-uploading the calibration to the AEM, and then cycling the key. After this process, the car typically starts without issue.
Recently, this AEM starting problem resurfaced. Despite numerous attempts to crank the engine, it wouldn’t fire. Frustrated, I decided to remove the AEM ECU and re-test all available ECUs. The original, supposedly repaired OEM ECU still failed to crank the engine. The two spare GE ECUs, as before, cranked the engine immediately but resulted in poor running conditions, mimicking a MAF sensor disconnection and causing the engine to die without throttle input.
After testing these three ECUs, I reinstalled the AEM. Surprisingly, after this ECU swap exercise, the car now cranks and drives correctly with the AEM. I didn’t even disconnect the battery during this process, highlighting the somewhat unpredictable nature of the issue. No laptop recalibration was performed; simply swapping ECUs seemed to resolve the immediate starting problem.
I’ve contacted AEM regarding the calibration issue, and they’ve stated that the ECU should not lose its calibration. They suggested the battery tender might be the cause, but I’ve used various tenders over the past decade without such issues on other vehicles. It’s worth noting that if the battery completely dies, the AEM ECU will indeed fail to crank unless the calibration is re-uploaded. This behavior is somewhat concerning for a standalone ECU system in a used car where reliability is paramount.
In addition to finding a trustworthy company to repair my factory ECU, I am also seeking recommendations for a company that offers remote AEM tuning services. Ideally, a tuner could review my current setup and ensure it’s optimized and reliable. As I’ve been accumulating parts for a turbo build, the reliability of the ECU system becomes even more critical. While I have all the necessary turbo components, I must admit I currently trust my older MKIII Supra more than my seemingly pristine MKIV, primarily due to these ongoing ECU uncertainties.
My immediate needs are twofold:
- Reliable repair of my factory MKIV Supra ECU.
- Remote AEM tuning to ensure optimal and dependable performance.
Recommendations for reputable companies specializing in these areas, particularly those experienced with used car ECUs and the specific challenges they can present, would be greatly appreciated.
