MicroSquirt.com read only forum (Jan.15,2018)

Hi people,

I have a BMW (e34 535i) which uses the factory Bosch Motronic 1.3 engine management on the mature and well-known M30B35 6-cyl engine (the last of the M30s). Traditionally people don't move these cars to 'Squirt much; it seems something reserved more for earliest motronic and L and K-Jet cars.

However I know a few of you might have done it or know: Therefore, may I ask for some advice?

I need to delete or replace the AFM (they wear out and are old tech) to get the car running right. I've been thinking of going MS for a while, even though for replacing just an AFM it is a little overkill.

Part of the reason I want to go MS is to pave the way for greater things such as adding a turbo.

However the crew over at http://www.millerperformancecars.com/m30.html have a dead-easy MAF kit. http://www.splitsec.com also do these, and seem to prefer MAFs on these cars. SplitSecond is no slouch in the proprietary EFI business, producing many of their own EFI kits. The PSC-001 is also interesting as it is a piggy back unit that can replace both the MAF or AFM in any such equipped cars- with a MAP sensor. I understand that this converts analogue output to the same signal Motronic normally gets from the AFM.

However what makes this hard so far is that searching around I have not been able to find much M30-specific stuff (most people do M20s and a lot use the MS-I). I guess I'd feel a heap better if there were people around with cars running MS-II on M30. Thankfully there is plenty of info earlier versions without Motronic and on the smaller-engined 325 and 525 models.

Digging around in the car for suitable places to mount the MS, I have found that both MS-I and MS-II are too big to install in my car. It'd need to be under the seat or in the glovebox and I really want to fit it in the car's fan-forced computer box.

However the size and reliability of MicroSquirt is a real boon. I'm thinking of asking to be on the list for a beta release unit. If I take the plunge, I fear that I'd really enjoy contributing some, esp. with testing and bug fixing (which is perhaps the last thing I need...)

Anyway, given the collective experiences here, may I ask;

• - What is the current state of play for supporting the stock BMW temp, TPS, VR and ignition?
  - Am I dreaming of being able to get into the beta call-up for MicroSquirt, or
  - as much as we all love an open solution, is a $300 MAF conversion a good option given the time it takes to build, install and tune a MS ECU?

Main issues for me;

• - MS compatibility with the M30B35 engine
  - I want to be able to tweak the ECU settings myself on my laptop
  - Flexibility with fuel octane, storing/restoring fuel MAPs
  - A future for the product
  - Cost

Many thanks for all and any input in advance- and sorry for the long post too
Pluto

hey plutonium, MSII as it is right now fully supports all bmw sensors, I'm currently running the same motronic version in my MSII v3 piggyback to a stock 1991 M5 motor, which uses Motronic 1.3.

However my motronic uses a MAF instead of VAF. However, if you're going to convert to MS then just get a FORD maf which will be built into the new MSII/microsquirt code as the baseline MAF. It'll plug and play directly, a splitsecond conversion is only necessary if you're using a stock bmw ecu for fueling.

Here's the deal, ms can be tweaked to whatever these sensors output directly, unlike the bmw system it doesn't need any kind of conversion boxes to make it think it's seeing another signal. As such any generic MAF sensor will work fine, i'm using my M5 maf, it's a little annoying as i have to generate my own curve (which is impossible at this time, as MT doesn't have a curve generator yet) but there should be no problem using any air flow sensor which works on a 0-5v range.

As far as all other sensors, they are all just fine, the TPS and temp sensors directly interface, as far as injectors, bmw used high impedance injectors, which don't need any special hardware and run directly off the MSII or if you use MicroSquirt, you won't need to add a flyback board, as MicroSquirt can run high impedance (16ohm) injectors stock (as per the information page at microsquirt.info)

If you have any further questions don't be afraid to ask, I'm sure what i said above is quite possibly confusing lol.

Eugene

Hi Eugene,

thanks for the update! Do you mean to say I have to use a MAF? Forgive my ignorance, but I thought MS avoided it (but was also compatible with other sensors like MAFs & AFMs) all that using a MAP sensor... or is it simply a bad option?

Thanx, pluto

plutonium wrote:Hi Eugene,

thanks for the update! Do you mean to say I ahve to use a MAF? Forgive my ignorance, but I thought I could avoid all that using a MAP sensor... or is it simply a bad option?

Thanx, pluto

You can use MAF if you want, but the default is MAP just like regular MS2. You will need to supply an external MAP sensor. The GM map sensor is a good choice since it can be fitted with a standard Weather-tite connector, they are all over the place in the scrap yards, and they don't cost much new either.

http://www.microsquirt.info/us_hardware.htm

Here is some alternate info.

http://www.diy-efi.org/gmecm/component_ ... nsors.html

Yay, no MAF (kinda appeals to my minimalist nature) LOL. Thanks a heap fellas, I just have to work out what to do with ignition now- if anything. Micro sure seems the way to go with this

I'm sorry, i didn't mean to say that you had to use maf, you just mentioned that you wanted to use a MAF conversion.

Ofcourse to start out I would use a MAP as it allows you to learn the system without having to worry about a MAF. However I've noticed in my few hours of playing with my MSII with MAF, that MAF input is much more linear and easier to use than a MAP.

Also, your engine uses a single intake plenum with a single Throttle body, that should make your car much easier to tune as a MAP than my M5 engine, in my case my kPA was WAY high at idle.

Good luck and enjoy the adventure:)

maddios wrote:I'm sorry, i didn't mean to say that you had to use maf, you just mentioned that you wanted to use a MAF conversion... Good luck and enjoy the adventure:)

No worries maddios. I bet your M88/S36/S38 really hums on the 'Squirt. There seems to be so much one can do. I'm really looking forward to this.

I can see the M5 would benefit from the MAF; it stands to reason that a single intake manifold will be more suited to the MAP. The reason I mentioned the MAF was that it was simply one of the options out there for Motronic people. In many respects it is overkill to replace an ECU just because of an AFM but a MAF is more expensive anyhow. Also it won't log data, scale to greater things or allow fuel/air map tuning!

Hah!~ MAFs? What contest?

Strike to B&G! Automotive companies: ZERO.

LOL

You can use MAF if you want, but the default is MAP just like regular MS2...

Great Scott, thanks. I just found someone else that has done a car like mine and he has good news regarding the stock sensors- it looks like they are all supported including the TPS that all the e34 community considers to be a 2 stage switch only. Very good work JohnC, thanks, pluto.

http://www.microsquirt.com/viewtopic.ph ... tps#127702

here's an interesting note plutonium. The tps switches used on the e34 cars motronic 1.3 and 1.2 are actaully full pots, however bmw ecu only uses the idle/wot switches. If you look at the wiring there are no wires going to the rheostat pins. I found it really weird at first when i was wiring my M5.

And yeah, all the sensors work perfectly fine, if you're going to use the MS as a piggy back, then you can use a value of 600 for the coolant temp sensor bias (in megatune) which is like a nudge for the bmw bias. with it you get the right number without having to install dual sensors.

Your car also has a VR sensor, and a 60-2 wheel, which work great with the MSII with the latest firmware, so you should have no problems on that end.

NOTE: i suggest you get your car running real smooth with MSII doing fuel only first, then switch over to spark, it can become a real handful sometimes especially if you're not sure if the problem is in the timing or fuel.