420A MS3X Losing Sync Randomly, error 23, 26, and 27, 420a

[Aaron Fliegler]

Hi,

I wired in my own megasquirt with a custom harness to my 420a EDZ turbo (2.4 bottom, 2.0 top, srt4 turbo) 2gb Eagle Talon with K20 coil on plug, and I have had all the car doctors look at it, and I can't get the desync to go away. The desync is regular and random, error codes 23-420A long tooth not found, and 26/27-pattern does not otherwise match 420A. I finally got the car to idle after 6 months of troubleshooting by turning the r56 pot counter clockwise. If i turned the pot too much, it just raised the idle and it was hitting boost. The R52 pot did nothing. Noise filtering only keeps the car from running and does not tame the desync. I have the tune from a knowledgeable 420a guy who does these all the time. I think the computer is bad. Here is a video, and I attached the logs I got today.

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[Aaron Fliegler]

I know it seems fast like I just found this problem and I solved it immediately, but its been four months. I put a 1k resistor in-between the signal and power on the crank sensor and it started right up no problem. The problem was I ordered a megasquirt for a 420a and it was not in fact built for 420a...

 

[BLACK'98DSM]

None of the Megasquirt units are assembled specifically for the 420a. They are designed to fit universally between all of the Mopar 4 cylinders of the era. Some of them have different electrical requirements and components. This is why they advertise it as "DIY"