ECU Purchase Question

[schroder]

I'm looking at purchasing a used 1991 Eprom ECU from someone on the boards. I'm getting a pretty good price on it, but he said the caps had been leaking. The ECU was pulled from a running car, and the last drive was only a 30 minute drive with no problems on the drive that he can remember. My question is if the ECU has leaky caps, but was still being driven, is it possible to simply replace the 3 caps with the 105 temp caps still, or how can I inspect for damage through photos. Thanks for any input you guys have and can help me with!

[damnslowtsi]

You can't really see all the damage (if any) on pictures. They have to be really high resolution to do that. If they started leaking relatively recently (I don't have any time frames on 'recently') then there is a good chance that acid hasn't eaten through the copper traces on the board. In this case you can salvage it by replacing the caps and neutralizing the residual acid on the board. If a car was indeed running on that ecu then you have a good chance of having a trouble free ecu for the days to come if you do those steps. Hopefully somebody will chime in and tell what to neutralize that mess with. I 've heard of baking soda before but really not sure.

[schroder]

Will it only effect the ECU if the caps are leaking while the car is running, or will there be negative consequences if the ECU has sat for a while with the leaking caps? Or, do the caps only leak while the car is running due to the heat from the ECU? Thanks again guys

[damnslowtsi]

They start leaking with time as I understand and the car doesn't have to be on for damage to occur. The liquid that comes out of the caps attacks the board and damages it. Just a chemical reaction.