'87 - up hole size for ECU harness

#1

Hi All,

I finished painting the interior this weekend and started installing/routing harnesses. The car is an '86 eta I’m updating with an '87 i engine.

I went to poke the ECU plug through the firewall hole and…no go! I took a look at removing the plug housing so I could poke just the pin board through and then reassemble the housing inside the car. That’s a no go too. The housing is a one piece affair that the cable is inserted through and then the pin connections made. I will not go the unpinning/repinning route.

So, it looks like I’m going to have to enlarge the hole in the firewall for the plug to go through. The hole currently in the firewall is ~1 3/4. Can anyone measure their later model car for the hole size. I guess this is my way of measuring 2X & cutting once.

Thanks,

KB

#2

I wouldn’t worry about the exact size. Just grab one of those door knob hole drills that are about 2" in dia and cut a hole. You’ll be threading wiring harnesses thru that hole at least once/year for one reason or another. No sense in making the hole such a tight fit that it’s hard to get the connector thru.

If you decide later that you hate the large hole you can always buy a big rubber grommet.

#3

'87 I - 2 3/8 in.

#4

Thanks for the replies guys,

I started with a hole saw tonite. Without the benefit of the pilot drill holding it in place, you’re pretty much wasting your time…it just jumps every where. I did try keeping the speed down to control the jumping, but it just isn’t practical.

I have a couple of pretty nice carbide deburring tools. I didn’t think I’d have much luck with them after my dash experience a couple of weeks ago, but I had to try a Plan B after the hole saw fiasco.

I opted for an egg shaped one and was quite surprised at the results. I guess my mojo was working because it was pretty controllable and removed a large amount of material pretty quickly. Once I got the hole enlarged/shifted, I cleaned up the edge with a bastard file and was pretty pleased with the results.

Final hole size was probably a little over 2 1/8". It was a bit of a snug fit for the seal plug, but I’m sure there won’t be any water sneeking by it. Lubing bulkhead grommets/seals with something like WD40 or slicker makes for much easier installation of such. I’ve got a can of some Honda cleaner/polish a friend gave me and it is the bomb for such activities.