• NAXJA is having its 18th annual March Membership Drive!!!
    Everyone who joins or renews during March will be entered into a drawing!
    More Information - Join/Renew
  • Welcome to the new NAXJA Forum! If your password does not work, please use "Forgot your password?" link on the log-in page. Please feel free to reach out to [email protected] if we can provide any assistance.

Need some Megasquirt opinions

WestfieldMX5

NAXJA Forum User
Location
.
I have a MS3 from a previous car that I'm no longer using, so I thought about using it on the Jeep. It's a 4.0 YJ, but not a lot of interest on the wrangler forums so I'm asking here.

Because the ecu is mounted under the hood, it has to be watertight and that's my main problem. I ditched the megasquirt case and bought a universal watertight case from Mouser. Of course the V3 board doesn't fit inside the case so I designed a new board to carry the MS3 processor.

I have 2 options and I'm not sure which way to go, so I'd like some opinions on which way to go.

First option: I desoldered the connector from a spare Jeep pcm that I had. My case is chosen so that the connector fits nicely inside. The mounting points even match those of the case. I'd cut the lid and have the connector stick through it. This way I'd have a 100% plug and play megasquirt. Problem is that I'd have to silicone the connector to the lid and hope that it's watertight. It would be a nice package but not so easy to waterproof or do modifications.

IMG_0064.JPG


Second option: I purchased a bunch of waterproof ampseal connectors (with gold pins for the best connection). I could install 2 of them in the lid and it would be 100% watertight. Downside, I'd have to make a boomslang harness from the Jeep wiring loom to the ampseal connectors on the case. Not so professional and prone to damage because it would be dangling under the hood.

IMG_0043.JPG


Thoughts?
 
It's got to be 91-95 if it has fuel injection from the factory. That would make it the first series of OBD I.
 
Correct, it's a 91. Once it's up and running I plan to convert to logical coils by replacing the distributor with the oil pump drive / cam synchronizer from a later model XJ / TJ.
 
It's got to be 91-95 if it has fuel injection from the factory. That would make it the first series of OBD I.

So??? Renix isn't fuel injected???
 
I might be interested in a pcb.
 
Amp connector!! You can't bend the laws of nature. Corrosion never rests. The poison they throw on the roads just keeps getting worse. I will ALWAYS lean towards sealed over convenience. I personally do not consider sealant a sealed solution but I'm picky about stuff I do for myself. The jumper harness would also allow you to relocate it to somewhere other than under the hood, inside the cab like a Renix XJ for example.
 
I thought about moving it inside the cab, but I doubt there is an opening large enough in the firewall. At the moment, I'm leaning towards the amp seal though.

Made a bit of progress btw.

IMG_0073.JPG


IMG_0081.JPG


IMG_0087.JPG
 
Were you able to find a 60 pin connector?
 
I'm interested in building one for the Renix. The trick would be to make the old PCM plug in along with the vehicle harness. Then you would be electronically able to switch between them on your command.
 
Do you have one of the renix plugs? I could try create it in KiCad and make a batch of pcb's that have both connectors, one on each side.
 
I have several Renix ECU's, but I think I can source them. I do lots of pcb layouts as part of my profession, so I kind of want to do it myself.
 
So basically you want to copy my design even before it's finished.

You guys could work together to accomplish what sounds like a common goal!
 
Back
Top