Watertite Megasquirt Project

[myk777]

Thought I'd post up some pics of my recent project since I hadn't seen anyone do this before. I needed a watertite enclosure for my Jeep that I'm converting over to MS2 (GM TBI conversion), I used a hammond case and an ampseal 35pin connector married to a v3 board with the relays and fuses all inside the box. The board is mounted to the case with 4-40 screws in nylon standoffs that are .43" long, there is no electrical connection between the case and the board this way. I could have used about a 2" shorter case but wanted to be sure I had plenty of room and space isn't a problem on the inner fender well.

I have the proto area pretty well maxed out with 2 peak and hold injector driver circuits, a cam input circuit (hall), constant baro and an analog input circuit for a fuel pressure sensor. Right now I have 5 extra pins left over on the ampseal connector so there's still room for expansion if needed.

Just have to finish mounting the relays and fuse holder and get them all wired up and it will be ready to mount in the jeep. If anyone has any questions feel free to ask, I have all the part numbers, pinout diagram etc...

Mike

[myk777]

Couple more...

[ol boy]

Have you done a submerged dunk test for any amount of time to see how much seepage there is? Now you can market an under water ECU for submarines!

Cool idea.

[myk777]

Funny you should ask, it just had to be tested didn't it
15min under there and it was dry as a bone, good enough for me

Mike

[myk777]

Here's the pinout diagram I used in case anyone wants to try this, it took alot of thinking as it was important to get the pins of the connectors to line up since the DB37 is a two row connector and the ampseal is 3 rows and the space to fit all those wires is pretty tight. For reference the pins on the ampseal are good for 17 amps each if you use the gold plated versions, that's why you see several connections going from two into one from the DB37 to the ampseal, might be a little overkill on some of them.

Note: there is a slight deviation from the manual in that I connected the WB02 power to the main relay instead of the fuel pump relay, just personal preference.

Mike

[Flat32]

I'm very interested in your installation, especially the Ampseal 35 pin connector. It looks like it would be just what I need to get from my passenger compartment, through the firewall and into the engine bay.

BTW, I'm in Federal Way, WA and would love to see your work firsthand. I had been running MSII fuel and spark with a GM tbi on a Ford flathead in a 1932 coupe.

Flat32

[Jonpro03]

That looks very cool!

[myk777]

I'm very interested in your installation, especially the Ampseal 35 pin connector. It looks like it would be just what I need to get from my passenger compartment, through the firewall and into the engine bay.

BTW, I'm in Federal Way, WA and would love to see your work firsthand. I had been running MSII fuel and spark with a GM tbi on a Ford flathead in a 1932 coupe.

Flat32

I purchased the ampseal parts at http://www.onlinecomponents.com the parts I ordered are listed below:

1 AMP/TYCO 1-776231-1 $12.36 (header)
1 AMP/TYCO 776164-1 $8.33 (plug)
40 AMP/TYCO 770854-1 $4.00 (contacts)


Note: The header is the gold plated version, however the contacts I ordered were the tin plated versions. I ordred these because I already had 20 gold contacts left over from another harness I made and that is plenty for all the high current wires in the loom, I'll use the tin contacts on all the low current stuff. The gold setup is good for 17amps, the tin is 8amps I believe. The part number for the gold contact is 770854-3 and they are 30 cents apeice so $12 for 40 of them instead of $4 for the tin plated contacts.

@Jonpro03 thanks for the compliments...I have it all finished now, need to snap a pic of it completed and post it up.

Mike

[S.Bretz]

Looks like a cool project.

...but my I ask: Why did you put injector drivers in the proto area and not use the standard spot on the heat sink?

[myk777]

Looks like a cool project.

...but my I ask: Why did you put injector drivers in the proto area and not use the standard spot on the heat sink?

The main drivers themselves(tip 122's) are in the "standard" spot as well as the flyback circuit and current sense resistors, just the logic control chips(lm1949) and some small caps and resistors to control them are in the proto area because there's no "standard" place to put them with the peak and hold circuit, all the stuff in the proto area is low current/logic level stuff. It's basically half of Jean's 4 channel P+H board but it's directly on the v3.0 board instead of a seperate circuit board, perfect for my application with only two low impedance injectors to drive.

Mike

[myk777]

Finally got this thing all finished up and tested on the bench works great, next step will be installing it in the engine compartment and wiring it all up. Thought I'd post one last pic of the finished product.

Mike

[Jonpro03]

Very cool. So on the DB9, only two pins need to be brought out?

[myk777]

Very cool. So on the DB9, only two pins need to be brought out?

Yep, the RX and TX lines, the only other thing needed on the serial connector itself is the ground, but I grabbed that from pin 13 on the DB37 header since it was closer to the ampseal connector.

Mike

[kritip]

Nice project. I'd have run and externa map for baro and MAP and run them in on the connector personally. Removes two leakage points, and also remove moisture in the pipes etc.

Very good though. Is it still going strong?

[myk777]

Nice project. I'd have run and externa map for baro and MAP and run them in on the connector personally. Removes two leakage points, and also remove moisture in the pipes etc.

Very good though. Is it still going strong?

Yep, working perfect...the bulkhead connectors for baro and map haven't been an issue, they seem like a fairly robust solution. The baro one keeps the case vented to atmosphere which may be a good thing?

Mike

[myk777]

I've had a few PM's on this topic regarding the p/n for the watertite case.

It's a Hammond 1550WGBK available at Digikey for $22.95

Mike

[tiagom]

This is great, much appreciated. I may end up doing the same thing myself.

[Vanhoe]

How did you bolt the PCB down in the box?