8051 weather sealing

[JD1964]

The 8051’s that come in LT1 equipment cars are mounted in the engine compartment from the factory. I assume they are designed to be exposed to moisture at some degree at least. Look the picture of this example in a 79 Malibu engine compartment. It’s on the right fender well behind the battery. Do you think rain can get in between the hood and fender gap enough to be problematic to this PCM?

6B76E869-7086-43C0-95E4-C2063A005D94.jpg

[steveo]

these under hood ECMs are resistant to flood, fire, heat, and minor nuclear explosions.how you have it mounted should be totally fine.

my biggest concern for weather proofing is gravity feed of any moisture wicking its way into the connectors, which really wont happen as long as your ECM wiring faces down like you have done

if you wanted to, you could take the ECM halves apart and give the ancient old seal a coat of dielectric grease to ensure moisture stays out. the ones i have pulled apart looked a bit 'flattened'.

some people say to ensure the ECM case is isolated from chassis ground (as it is in the factory) however i have mounted them with solid aluminum brackets on a few cars that are still running a decade later.

[Tom H]

In addition, on my '97 version, there is a small (1"dia) button in the case. If memory serves it might be on the cover for the knock module. This button has a Gortex fabric pressed into it. This permits condensation to escape. The boards are conformal coated but the ribbon cable is not water proof at the connector to ribbon connections.
I worked a number of years designing rugged terminals. This sort of arrangement is not unusual. The case and thus the Button should be oriented such that water can't sit on it. I am sure the factory bracket does this (but haven't looked)
This is part of the reason I think that sockets and/or removing FLASH from the board is a poor idea unless the coating is re-applied.

-Tom

[JD1964]

Thanks for the good news gents