D1 no start after splashdown

I'm looking for advice on next steps.

After driving through a puddle a the third time, my D1 shut itself off. I can get the starter to turn over, but I?m not getting spark. Sometimes I have to run through the gears to trick the neutral position switch. With the ignition in position II and III, I hear a loud clicking noise from a yellow relay under the glove box (I can feel it too). I've swapped the relay with no change. I dug into the RAVE manual but the relays in that area look like: condenser fan, power wash, ABS load, ABS warning. None of these seem related to the ignition.

I pulled the ECM and disassembled the box. There were a few mud drips on the boards but it was not wet when I got there (24 hours later). I sprayed the boards down with electrical parts cleaner, cleaned the pins and used dielectric grease when putting it back in the truck. No change in symptoms.

There was a build up of mud behind the passenger fender in the engine bay. Enough moisture has been there to rust out the washer reservoir bolts in the fender. Water could have gotten in where the harness feeds through the firewall, but nothing obvious.

Some research on the forums suggests there is a"hard reset" that could be done with the proper computer. Is that true/necessary?

[1997, D1, GEMS, no prior electrical issues]

I posted this 24 hours after it got wet. Apparently 48 hours was what it needed. The clicking went away and she fired up with a little struggle. After idling a bit, she fired up like nothing happened.

I'm surprised it was so easy to have a water problem. I'll seal up the ECU and clean up around that fender to try and lower the chances of this happening again.

Maybe this is a dumb question, but assuming the ECU was the issue, could I have swapped a dry one in and been on my way? It's not the type of part I would think of as a "trail spare" but it was pretty crippling. As it turned out, the puddle was a just a dirt road from town and we easily coasted and towed it to a spot where AAA could get me. However, it's not hard to imagine getting bricked in a bad spot - especially if I was solo.

How similar are ECUs across the D1 families? Is there any programming required when swapping them out?

stu454 said:

Maybe next time don't splash into a mud hole like The Dukes of Hazzard?

Click to expand...

but all the D2s and LR3s were doing it...

Thanks for the input. I'm planning to: clean the boards with isopropyl alcohol and a toothbrush, let dry, then apply a conformal coating (Konform SR Conformal Coating) to the boards and use grease on the connection pins.

I'm 50/50 on using silicone to assemble box since the coating claims to protect against water. I'll start with just the ECU and hunt down other electronics if this works.

I'll take pictures and report back!