Motronic 1.3 To MegaSquirt

[sfdon]

12138530118

 

[sfdon]

Hint- you need 11 for a 1973 and only 10 for a 1974 model
buy from overseas, NOS to be correct.
check ebay.

 

[richiemcb]

In the beginning I wanted to do and learn as much as I could about MS by myself , I had no idea how the harness was going to be so different from the standard old bmw harness.That is where Don throws the curve ball right at your head but goes right over the plate...
You see He has done this before , there are things in the harness I had no idea about. So here I am ... helplessly waiting.
[/QUOTE]
I have fitted a MS to a Mercedes Pagoda from scratch - if you have any specific questions on MS let me know and I can try to help.

 

[HB Chris]

Same one that mounts ground strap next to battery. I use BelMetric.

 

[BarryG]

Well I have been busy but not on the Coupe.

Redoing our master bathroom took priority, it’s a big project, stripped it down to the 2x6 framing . Took out the tile shower & Bath tub and removed tile floor.
Now it’s time to put it back together.

I have put in some time on the swap with the help of a pro.
?

 

[richiemcb]

Not sure what your question is ? Normally you would just buy the sensor pre wired along with a controller. If you are trying to reuse an existing one the video covers it I think. The O2 sensor will have a controller which will output a voltage that the Megasquirt will read - the O2 sensor does not directly connect to the Megasquirt.

 

[sfdon]

Umm- I thought I gave you a link to the Wideband sensor you need for MS?

four wire O2 sensor is no good for MS
That looks like narrow band with heater circuit

 

[BarryG]

Thanks for the link Don

This is my harness that Don put together and those wires are for the 02 sensor and Bosch said do not solder the wires. Just want to know how to connect...

 

[sfdon]

The wide band unit has two inputs from the harness - battery positive and ground. That’s the red and brown wires you see.
They match up to the wide band units red and black wires.
The wide band has one output wire to the harness - a white wire.
It connects to the white/black wire you see. It’s white/black as a visual cue that it starts off as black and becomes white in the circuit. When you buy your wide band unit you will also see a blue wire- trim it heat shrink it- it is unused.

 

[BarryG]

Whoo look at this

Stroker Crankshaft – M30

Each

www.iemotorsport.com

 

[Bearmw]

At first I thought this was fake like the World Products M30 aluminum engine blocks that were an April fool's joke a few years ago on R3Vlimited.

 

[BarryG]

The slow process goes on. This past weekend I pulled my exhaust to get the 02 sensor plug out. I’m not reusing the exhaust but I need to keep it in order to start and communicate with the MS. I will swap it out for the Stahl headers and all new tubing.
some of you may have seen Riley’s Trans Am . He a Sacramento kid with awesome talent. He is going to do my exhaust.
Check him out on Instagram

 

[BarryG]

Well I think I’m all hooked up and ready to start the engine up. I’ve had some great help getting the wiring sorted out. I went to a distributor from the motronic cap n rotor. Changed the original alternate to a better one wire Alt. Eliminate the fuel pump relay under the rear seat , didn’t need it because there the harness has one along with the main relay

i still need to bleed the brake and slave and put the car back down on the ground.

 

[BarryG]

 

[BarryG]

Everything checked out so we started it up today and it fired up first try. A long way to go but hey ... it runs

 

[BarryG]

Lets finish this thread up.
First things first I got say a big thanks to Terry C for helping me out with the wire harness and so much more. He was my main go to guy. Thanks also to Don for supplying parts.
The Megasquirt really smooths everything out,Idles is perfect and the throttle response up to 6 grand is what I wanted. I really don't want to push it too hard with the new head. My son and I take it out almost every day. I have a great local independence shop that will pull the power out in the next few weeks. Oil change and recheck the valve clearance are to come. I need to take my headers to get the surface rust removed and then coated. Then install the headers and off to get a new exhaust built.
I will get some pic's and a video

Thanks for hanging with me

PS my bathroom remodel came out great...

 

[aearch]

hey barry
darn thats one beautiful set up - great job

 

[Bearmw]

Looking good. It will be nice when the motor is fully broken in.

 

[Peter Coomaraswamy]

Barry, this thread brings back brutal memories... or maybe flashbacks!

 

[Rek]

Hey I didn’t give up there are just “ Days Between “
I have a few things to get right before I rip into the Coupe... in this order.

1. I have a dead spot in my ECU / Harness that needs to be found. The problem is that when I push it to around 4-5 grand it cut/backfires, not good.

2. With COVID-19 I haven’t driven it in months and when I did take it out last weekend it ran fine , but when I got home I left it on the driveway for 10 minutes and it would not restart. Checked everything, turned out to be the pulse sensor on the balancer. But still cuts ou t:-(
But hay I’m going Megasquirt.

3. Then there are all the engine changes.
Schrick cam - Head work.
Clean and coat the intake bits.
Get my Stahl headers coated - new exhaust behind the headers.

So it’s like cooking a good meal... it all has to come together at the same time.

I’m not sure if I should install the Megasquirt first or after the mods. Going to go see

I had this and presumed fuel pressure as it was related to the speed of the engine. After messing around with that for ever, it turned out to be the distributor arcing at higher revs. A quick clean resolved that.