REBUILDING MITSUBISHI ECU/ ECM’S
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Mitsubishi specified certain electrolytic capacitors from 1989 through 1994 made by Rubycon Electric. Here is the most common culprit of ECU trouble: Over time and at repeated elevated temperatures these start to degrade. The liquid electrolyte begins leaking from the seal on the bottom plug of the capacitor. This liquid is very corrosive and conductive. It interacts with the humidity coating on the circuit board causing an array of problems. Among these are: injector trouble, erratic start, stalling, rough idle, check engine light, etc. This leaked substance begins to spread and react with metals in its path. It gradually causes erosion of copper traces and shorts in circuit paths. At first you may notice intermittent problems that occur from this. Most often though, the degrading capacitors continue to operate within tolerance and the damage remains minimal. This is where we want to pull the unit and get busy. If nothing is done, problems surmount. The breakdown of the humidity seal, corrosion and shorting of circuits, and ultimately, the loss of other critical components in the ECU. (i.e. large voltage spikes that cause major damage) all lead up to an untimely demise. At this point you may actually smell something burning inside the unit. (This fried electrical smell is putrid to say the least) The idea though, is to get to the source of the problem before you reach this point. Not to say that it isn’t still repairable. But the longer the problem is ignored, the more difficult a task it will be indeed.
Mitsubishi specified certain electrolytic capacitors from 1989 through 1994 made by Rubycon Electric. Here is the most common culprit of ECU trouble: Over time and at repeated elevated temperatures these start to degrade. The liquid electrolyte begins leaking from the seal on the bottom plug of the capacitor. This liquid is very corrosive and conductive. It interacts with the humidity coating on the circuit board causing an array of problems. Among these are: injector trouble, erratic start, stalling, rough idle, check engine light, etc. This leaked substance begins to spread and react with metals in its path. It gradually causes erosion of copper traces and shorts in circuit paths. At first you may notice intermittent problems that occur from this. Most often though, the degrading capacitors continue to operate within tolerance and the damage remains minimal. This is where we want to pull the unit and get busy. If nothing is done, problems surmount. The breakdown of the humidity seal, corrosion and shorting of circuits, and ultimately, the loss of other critical components in the ECU. (i.e. large voltage spikes that cause major damage) all lead up to an untimely demise. At this point you may actually smell something burning inside the unit. (This fried electrical smell is putrid to say the least) The idea though, is to get to the source of the problem before you reach this point. Not to say that it isn’t still repairable. But the longer the problem is ignored, the more difficult a task it will be indeed.
Tags: mitsubishi
