I'm getting ready to install Megasquirt (MS-II) in my `70 to replace my D-jet. I'd like to put the ECU behind/under one of the seats and the MS relay board under the existing relay board.

What have you done for routing harness wiring from the interior through the firewall?

What other options?

Photos of your harness install would be great.

Thanks,
Brian

This is SDS, but you could do the same with MS. This is a AMPSEAL 35 pin connector. They're expensive and challenging to assemble because you have to deal with 35 wires/pins at once on the female side, and the male side needs wire soldered to pins and each wire needs its own heat shrink and everything is really close together. But they are a completely weather proof and pretty compact.

Brian, I am doing the same thing this winter. Could you post up what you did with the various parts? I've got the MSII and the harness and am intrested so see how another 914 guy did it.

Zach

I think there is a link in my signature to my SDS install. It should show a photo of how I mounted my controller and wires. I just made a hole in the firewall for the connector to go through, maybe 1" or so. I then adhered a piece of aluminum that had a small hole for a grommet. I didn't add any additional connectors as I thought those could be places for problems. I also mounted my conroller in the area inside the back pad. I think this actually worked out pretty good. Photos should also be there. Good luck. JoeO

Zach,

So far:

MS-II
MS Relay Board
Wide Band O2
Using existing 1.7L injectors with PWM
Using existing CHT
Using existing intake air temp
My IAC valve still works so I am leaving that in place.
I'm pulling the tach input off of the neg side of the coil

I have not bought a TPS yet - SDS has one that will fit. I'll just use a piece of aluminum flat stock to make a transition/mounting plate.

My initial direction is to just do fuel only and tune it then if all is OK go to ignition control with a "locked" dizzy.

I'll post my progress when I have something to show. So far I have just completed and tested the controller with the Stim and the laptop.

More later...

Cheers,
Brian

Thanks Joe! Great write-up.

Brian

This could be a general question, that anyone can chime in: Do you really need a TPS? The Map sensor should be good for load sensing. I have a MS install on my 2.7l - 6 engine, and I just use the MAP and works fine.

Anyone?

Also, I did as Joe said, and cut a 1" hole in the firewall with a grommit and just feed the whole connector through. There is a link on DIYAUTOTUNE.com that shows someone doing exactly that.

Hope that helps.

-- brett

I ran my FI wiring harness thru the passenger side heater tube (I have a H2O conversion). I cut out a bit of the passenger foot rest foam and stuck my ECU in there. I didn't want to cut the firewall. I know you can get a really long 12' MegaSquirt harness. I'll post some pics when I get home.

-Robert

I really like the delphi weather pack connectors.
Bulkhead connectors are well priced and use only cripmed joints for ease of assembly and reliability.
http://www.ebay.com.au/itm/Delphi-Packard-...993251737835069
the crimp tool to match should only cost you around the $30 mark for a good one and it will do all weatherpack connectors for the rest of the install.
Edwin

If you get a microsquirt, it's pretty weatherproof and you can mount it in the factory location. Check out the left side of this pic

Thanks. All great ideas. Keep `em coming.

Anyone else use the relay board?

I'm leaning towards using the 1" hole and grommet. I just hate cutting holes - seems like rust does a fine job on its own.

Brian

I have done it with and without the relay board. It does make it easier if it is your first time but in the long run just winds up being more stuff that you have to figure out where to mount. once you get the hang of it you will want to ditch your relay board and just tap into the stock relays

I used this on the firewall for my rear harness.

Click to view attachment

Click to view attachment

I'm also preparing to do an MS upgrade soon. I got a TPS from a BMW 1980-84 Throttle Position Sensor, # is TPS 0280120406. found on eBay. It bolts right on and if you can find the connector as well it should come with 3 shielded and 3 unshielded. The Shielded are the connections you want to use. This TPS was used with a potentiometer for the Automatic Transmission.

I'm also planning to use the 2.0L plenum with a Wells AC320 IAC. I'm going to modify the AAR plastic inlet on the side of the plenum and use a mounting plate for the offset bolt pattern. After a little creative drilling it should just mount right up. The depth is perfect for the IAC's full range.

I'm going to use the Innovate MTX WBO2 sensor and gauge kit for my AFR.

I have a spare motor and harness that I will do my mock up on for a fuel only install which I will follow up with the Crank Sensor and EDIS 4 ignition.

I bought the Crank and wheel from McMark, very nice setup and it goes right behind the impeller.

I'm using some Army Grn Y2M-37TK 37 Pins Circular Connector to create the quick disconnect on my firewall so it will be plug and play. With the proper heat shrink it should be completely weather proof as well. Found them on eBay.

The MS Box will go under the dash or the passenger seat but I'm inclined to put it under the dash. Under the dash will help with my future CarPC install for tuning, data logging, media center, navigation, etc.


Good luck with your project. Can't wait to see some pics.

AFAIK, the relay board is NOT weatherproof. That would preclude it from use in the engine bay of our cars. I would mount it under the seat with your ECU and run the wires through one of the Delphi connectors as others have suggested.

On my '67 VW Squareback, I have the relay board under the seat and only have the harness exposed to the elements.

You NEED the TPS. The MS ECU needs both MAP and a TPS to "triangulate" the engine's fuel requirements. Just like GPS needs 2 satellites to know where you are, the ECU needs both MAP and TPS to know what you need.

Consider EDIS or COP for ignition. Once you have the tunability that these offer, you will NEVER go back to a dizzy again. Dizzy's are just a compromise. . .

If you want an MSQ file that is close for a stock 2.0L motor, PM me.

I agree that a TPS should be used but, Bits racing offers a MS Partial kit that converts a flat six to MS EFI without the TPS. They just use the MAP. They say the difference is hardly measurable. A TPS is not hard to find though and is pretty cheap.

As far as the relay board, the stock 914 relay board should be fine. You have two 12v power outputs (one for the injectors and one to MS) and one Fuel Pump output to the MS (comes directly from the FP Relay and MS provides ground) and that should be all for fuel only. There is even an extra 12v out that would go to the Cold Start Valve that you can use as a switched 12v supply to the O2 sensor. If your using an IAC instead of the AAR then you can use the 12v supply from the AAR as a switched 12v line as well.

When you go to ignition control, then you may have to piggy back another 12v supply or come right off the fuel pump 12v.

I haven't finished tracing the schematics but I pretty much have it all in my head. I'd like to make a standard harness that can be duplicated but it's all theory and notes at the moment.

BTW, here are some helpful links that will help with the D-Jetronic Wiring harness and the specs for the current sensors.

Tells you all about refurbishing the D-jet system but most importantly, the pin outs of the ECU. I used this to trace back the wires to the Relay board.
http://www.rennlist.com/techarticles/djetronicfuel.htm

The best spec information on D-jet by far. You can find the spec for the temp sensors so you can set it correctly in MS Tuner. Unfortunately, some people still report problems with one wire sensors, so I myself may just do the CHT modification to make it two wires.
http://members.rennlist.com/pbanders/DJetParts.htm

I say go for the TPS.

Mega/microsquirt have the ability to control the "mix" of the MAP and TPS signals when it calculates the fuel for acceleration enrichment. It's literally a slider in megatune...full left is TPS only, full right is MAP only, and the middle is an even mix.

For my engine with my tuning tables, I found the smoothest acceleration enrichment with a 80/20 MAP/TPS mix.

YMMV...figuratively and literally .