The m20 Motronic m1.3 to m3.3.1 thread - Fully working now!

[HairyScreech]

I have been saying for a while that i would get the info up for the m50 single vanos ecu conversion for a while so i thought i had better get on and post it up.

I worked this one out a while back but have only just got the bits and time to start on it a bit.

The plan has always been to get the m20 running on the m3.3.1 ecu similar to the m50 non vanos m3.1 conversion (yes i know this number of 3s and 1s is going to get confusing) a few people have done before.
However the m3.3.1 is a little better than the non vanos m3.1 it adds knock sensors and gives a proper hot wire maf that can be swaped with other bmw ones as the m3.1 one is unique and a bit of a sticking point by all accounts.

The benefits of doing this over the m20 m1.3 are huge, this ecu is pretty much as good as it gets for a stand alone or home fit ecu, the resolution of the maps is huge compared to the m1.3 or most after market ecus.
Benefits are:
1. increased map resolution
2. sequential injection
3. coil on plug - ditch the shoddy distributor set up
4. variable resistor TPS
5. MAF rather than AFM
6. Knock sensing
7. Proper closed loop lambda control operation
8. better idle control
9. other things i have forgotten about.

With that out of the way onto the useful stuff.
Some of the bits of the conversion are the same as in here:
http://www.e30tech.com/forum/showthread.php?t=63504
So for bits like the cam sensor trigger etc, all credit to their respective inventors.

The plan has been to keep the m1.3 loom as it is already custom built for the e30 and a lot of the functions of the m3.3.1 are shared with the m1.3, in that it would be a waste of time building a customized loom for the m3.3.1 when i could just piggy back onto the m1.3 loom.
This has resulted in chopping an ecu connector out of a m20 325 m1.3 ecu that i suspected to be faulty and using this to make a plug and play solution routing most of the stuff via the origional loom, the upshot of this is unplugging the m3.3.1 loom from the m1.3 loom and plugging a stock ecu back in is all that is needed to go back to m1.3 (bar swapping a few sensors etc)

First thing to do on this front was to work out what needed to go where.
I have since built this part of the loom and tested that things come out to the correct pins so i am fairly confident that this part of the conversion is ok so far.





(please excuse the spelling and if the hand writing is a little incomprehensible then just say and i will type it.
Be aware these are huge scans and following the link will bring up larger ones)

The original info comes from 1996 BMW 318is-c - 320i - 325i-c - 328i-c Electrical Troubleshooting Manual.pdf which is available online. (googling the file name will bring it up for dl)
using the M3.3.1 section wiring diagrams and a set of bmw e30 diagrams everything was matched up as close as possible.

Down the left hand side i have written the m1.3 pin that the m3.3.1 loom needs to be connected to.
Anything marked add is a function that is not present on the m1.3 loom or needs specific wiring alterations that are best just added for reversibility sake.
There are notes to the function of each pin written on the right.

[HairyScreech]

The plan to get around the AFM to MAF issue is to do a similar thing to the m1.3 maf conversion.
I intend to get a plug that fits the AFM plug and make a short conversion loom extension that moves the air temp sensor and AFM pins to the correct place and plug type for the MAF and separate air temp sensor.
A diagram for this will come when i get onto it.

The solution to the m3.3.1 sequential injection being able to trigger the m1.3 batch injection will be to add diodes to the batch injection earths where they join the separate sequential injector earths.

The TPS, Air temp and coolant temp need a common earth that goes to the ecu on m3.3.1 pin 44, this will be added with the loom extension for the MAF and a small extension for the tps (which will be able to swap the outputs if its backwards like the icv)

The solinoid for the VANOS should come in quite handy in my case, i plan to use it to switch an M54 DISA valve to get twin resonance as its output matches the function of the DISA valve perfectly.
Off at idle - on between 1k and ~4.2k - off from 4.2k to redline.
This will give a similar effect to variable intake manifolds on other engines.
For anyone else a simple VANOS delete chip is the answer and just leave it unplugged.
This could be done along with a EWS delete if not using the red label 413 ecu.

The first shot at this can be seen draped over my project engine in my latest project post but i'm not quite happy with the coil/injector bit, it will work fine, however i plan to revise this soon.

[steve_k]

Wow looking good dude.

i'll be keeping my eye on this thread so I know what to look for down the scrappy lol.

I'll be downloading that PDF file to show a mate of mine who knows what he's doing with car electrics.

[steve_k]

Forgot to add,

how easy/hard would you rate this whole conversion for someone to do once you got it all sussed out?

[HairyScreech]

Figuring how everything needs to go together is the hard bit, once the bugs are worked out then its going to be simply a case of cut x wire and wire to x.

Once the leg work is done then it should be pretty straight forward.

Will upload the diagrams from both that pdf and the e30 one that i have been using so far in a sec.

[steve_k]

Chhers dude looking forward to seeing how this pans out.

fingers crossed all for the better.

[HairyScreech]

ok this is the M3.3.1 m50tu wiring info.

[HairyScreech]

and here is the equivalent for the e30 m1.3

[steve_k]

Well I guess I'll be printing them off to go through later.

I take it the parts scribbled out on the M3.3.1 diagrams won't be needed in the conversion?

[HairyScreech]

Now some of the specifics of this, By using the m1.3 loom a lot of the 12v and 5v feeds are already dealt with and the required inputs to the car loom are all there.
The only things we will be intercepting are things that enter the ecu.

For the sake of this we can ignore things like the dme relays and the starter motor and alternator as all of these things are not being touched and will stay the same as a stock e30 wiring.

the Lambda heater relay and its associated wiring don't enter the ecu and are present on the m1.3 loom, so this should remain stock and only the black and yellow signal wires need touching, thus the green and brown of the m3.3.1 loom will be left over, these can be ignored or cut short.
the emc shield could benefit from earthing at either end however.

Injectors need there 12v feed from the m1.3 loom, i am not quite happy with the solution to this atm so will be tweeking this, i think it may be simpler just to add 6 individual earths rather than tweek the loom to the m50tu injector box, i will go over this again later on.

[HairyScreech]

Well I guess I'll be printing them off to go through later.

I take it the parts scribbled out on the M3.3.1 diagrams won't be needed in the conversion?

The things scribbled out are parts that are not relevant yes.

What i did was to spread the m50tu loom out, remove 90% of the wrap, and spread it out like a giant spider.
at that point i left the crank sensor wires and the knock sensor wires alone as they go all the way back to the plug uninterupted and they are shielded.

The cable for the injectors was untouched as again it could be separated all the way back

Everything else was cut off around 12" from the M3.3.1 plug.
The intention of this was to be able to loop it around 360 so the two plugs could face the same way and the ecu could use the same mounts.
A lot of the m3.3.1 wires go to the plug and the few that don't would then need re-connecting.

pretty much open the m3.3.1 loom and cut everything that is not a shielded cable, everything else will be re routed easily.

[HairyScreech]

This can be seen (just) here, i will get some better photos later.

[driftwood]

Could this ecu run an itb set up?

[steve_k]

Just a thought would it be possible to mount the coil packs on top of the rocker cover using a spider plate? I thought it would make it look a littlebit neater thats all.

or am I talking out of my rear??

[HairyScreech]

Could this ecu run an itb set up?

Only if you run the throttles like an e36m3 and use a large plenum to allow the maf to work.

However m20 itbs are a thread of there own as most throttle are useless for anything other than a full race spec 9k rpm m20.

[HairyScreech]

Just a thought would it be possible to mount the coil packs on top of the rocker cover using a spider plate? I thought it would make it look a littlebit neater thats all.

or am I talking out of my rear??

Yes it would be possible, however i want to keep the coils as close to the plugs as possible for the obvious reasons.

In those pictures they are unsupported although you might notice some renault coils nearby that might end up on there instead as they look much neater.

I want to get shot of the wires that run over the cover and use the smaller m20 plastic case for the injectors and the m52 coil loom down the rh side of the engine for the coils.

pic of an altered m52 coil loom that i did earlier in a sec.

[clarko74]

Very interesting, I will be keeping a keen eye on this. Keep up the good work Mr Screech.

[Lurch320i]

Could this management be used with a turbo? as it would save messing aroung with megasquirt?

[HairyScreech]

No idea, take a look to see if anyone is using standard engine management on a turbo single vanos m50.

If you did use this it would be sub optimal however, this system was intended for the m50tu and not for a turbo engine.

[steve_k]

any updates dude? waiting on the latest info.

[HairyScreech]

Short answer no, long answer - I'm totally fking broke and trying to finish the dissertation module I had to carry over to this year.
I hope to solve both these "issues" in the next couple of months so our regular service can continue.

[Ant]

Biggest issue I can see with this idea is the ignition timing will be far from optimal 2V vs 4V heads, piston and C/Chamber shapes etc.

Cheap maybe but far from optimal unless the mapping is revised IMHO

Just my tarnished 2p worth

[Grrrmachine]

I saw a similar concept on another forum and was really intrigued - I presume the main benefits are better throttle response combined with better economy?

Also, I haven't seen your solution for cam timing. How are you solving that?

I'd be really interested in doing this to my own once it's tried and tested - only seems to be about 200 quid for all the parts.

[HairyScreech]

Biggest issue I can see with this idea is the ignition timing will be far from optimal 2V vs 4V heads, piston and C/Chamber shapes etc.

Cheap maybe but far from optimal unless the mapping is revised IMHO

Just my tarnished 2p worth

My biggest concern as well, there are as many things to say it will be ok as there are to say it won't.
Suck it and see and if its an issue then remap time.
The 3.3.1 is a very advanced ecu and looks pretty good next to some of the aftermarket options, even with remap costs it's a cheap ecu upgrade.

Grr, I will draw the cam trigger and plate up in CAD asap so you can see what I have planned, its been done before on the m3.1 conversion linked earlier in the thread.
I need to make a similar plate for a mates drift car ( going standalone with cam trigger) so a CAD version may make it easier to get a couple made.
End of the month once I have this work out of the way i expect.

[Ant]

Something else popped to mind

the M50 non vanos was E30 style trigger wheel (402/3/6 ECU Iirc)

Iirc the the M50TU has the missing tooth more advanced ? Would that affect the swap , I never tried M50 trigger wheel on M20 crank with the inner timing cover in place (413 or later)

Got all the maps for all so when the time comes I can clone the M20 OE timing maps onto the M3.x if required Screech

[HairyScreech]

Yeah your right, I know about this. I was planning to either relocate the sensor bracket if possible or weld a tooth onto the wheel and take one out where needed.
Failing that just tack an after market £20 trigger wheel to the crank pully.

The M50NV has the trigger in the same place as the M20 so it would be simpler for an easy swap, The M50TU has it in the same place as the S50 and M52 however the benefits of the more advanced system out way the difficulties of this (well to me anyway).

Timing maps sound good, I expect to be well off with the VE but the timing shouldn't be too far away for the most part. From what I have seen (and you have mentioned in the past) these things are VERY tolerant with regard to timing.


http://www.e30tech.com/forum/showthread.php?p=739765
This is the cam trigger method I am thinking of going with.
Plan to make a CAD drawing as above so others can be made in the future.

ETA - link helps simon, link helps.

[gromgsxr]

im using that method for the cam trigger on megasquirt if you do end up getting the bits made i could be interested in them if you get spares

[HairyScreech]

IIRC you were not far from me Gromgsxr? I'm in mid wiltshire area.

[gromgsxr]

no i'm a fair old way away from you not far from Norwich

[Grrrmachine]

If you're going to get these trigger wheels machined, then it might be worth a group buy as I'd be interested in one.

[HairyScreech]

ahh, np, there is someone with a similar username who is pretty close by, bradford on avon way i think.

Grr - Might look into it then, hopefully should have some improved cashflow in the next few weeks and can spend some on the e30.

[clarko74]

Did this ever get any further?

[HairyScreech]

Right, with a few life changes and a Z3 2.8 to use as a daily this is all back on.

With another car to drive to work I can pull the E30 apart as much as I want.

I dragged all the wiring out the back of the garage, stripped the stock loom off the E30 and started throwing new bits onto it.

First off had a play around with the stainless steel M52 fuel rail. Its a more compact unit and the fuel lines enter at the back of the bay, which given that E30 lines are prone to leak on the engine (fire risk) is a bit + in my book.
FPR is 3.5 bar instead of 3.0 bar which is a shit as it will mean 16% over fueling. Might be able to get around it with an adjusted chip for the M1.3 but it is correct for the M3.3.1.



The fit seems pretty good, had to make some tabs to hold the rail in place but with those on it's not moving anywhere. The vacuum take off needed rotation 120 to go to the back of the head but I feel it's actually neater like that.
Fuel hoses come up and inbetween the heat hoses. Almost seems made for it.



Having done that I noticed the injector box from the M50tu will no way in hell fit in the gap and onto the injectors, transplanted the modified loom back to the M20 box, shite of a job to do that last night.


With that done I started firing the modified M1.3+M3.3.1 loom onto the car.
Laid it out first on top of the engine, like that it look like there is so much compared to the M1.3 loom.



[http://i159.photobucket.com/albums/t157 ... q0ro3r.jpg[/img]


Got this far before rain stopped play (you can see how hard it had started to rain from the drips).





Almost looks factory when its tucked in.

Things to solve now:
1. FPR pressure difference, will be able to fire it up on M1.3 but it will be 16% rich, and adjusted chip may be the way to go so I can do a dyno run with this set up then change to the new for the second run.

2. Not sure I can get the ECU plugs through the hole in the bulk head becuase I have done all this off the car. Need to work that one out.

3. need to test the diode set up on the injectors to see if the sequential injection will earth out the batches, I think the diodes I added should stop this.

4. need to check the loom I used was a facelift loom. Don't want to set fire to the car due to the 12V swapped with earth pin issue that can happen when mixing early and late looms.

5. start the car up on the M1.3 to check the loom works before cracking on with the M3.3.1 changes.

[HairyScreech]

Went back out and pin 20 on the C101 was indeed a brown wire, this has been cut of an insulated and the pin stub has a blob of silicone over the pin.

No magic smoke escaping from this loom.

Not much to go to test firing on the M1.3

Edit - Check the warning here for more details.

[Brianmoooore]

A lucky escape! It doesn't really seem to be a late/early thing, so should ALWAYS be checked.