E28 Megasquirt FAQ

[Shadow]

Yeah, gets rid of the whole detonation limit thing

[12valves]

What does it take to keep the stock MPG gauge working with megasquirt? Has anyone done it?

[Brad D.]

What does it take to keep the stock MPG gauge working with megasquirt? Has anyone done it?

Something like this is what you need. I don't know if anyone has actually tried it yet though.

[projenitore28]

WOW all I have to say is wow and thank you!!!!

[Kilomph]

I can't seem to find any information on Megasquirting E28 M5s, can somebody point me in the right direction?

[Lurker27]

Brad (if you're still around) do you have multiply MAP disabled? It sure looks like it

[Brad D.]

Yes, multiply map is disabled. You really only use this if you are running a secondary map to rescale portions of the base map or to scale low VE value portions of the map to give you better resolution. It has its uses but I never found a need for it.

[Lurker27]

It is usually on by default, isn't it?

[4evere30]

great write up ! does this apply to megasquirt 1 v2.2 ass swell?

[saQ]

Has anyone done Wasted spark with original crank sensor with the 35pin motronic 1.0? Is it possible? With megasquirt of course.

Edit: My bad, already found the answer.

[Xenocide]

I made an adapter harness and ran a new shielded wire for the crank sensor, which worked just fine. You just have to source the 60-2 toothed wheel, sensor, and bracket. The boss is already in place and the holes are tapped (or at least they have been on every m20 I've encountered).

If you enjoy punishing yourself, the RX-7 dual VR trigger adapter board can be made to work with the stock sensors. As far as I know this hasn't been done before, but it is technically possible.

I wasn't running wasted spark, but I easily could have, it'd just take new wires for the coil packs.

[tacomagabe]

So I have an e12 that i just got a b34 for. My plans are to go to MS, and once I have it tuned, go FI. I want to just transfer my intake and l-jet over to the b34 and run that until I want to go to MS. I don't see the point of collecting all the motronic 1.3 stuff if I'm going to be going to MS in the future. As far as I know I just need the crank sensor that is already on the b34. anything else? My question is if there is anything else on the motronic system that makes it a better transfer to MS. Better then starting with l-jet. I tried to search for this answer but couldn't find it. Thanks for any info.

[12valves]

I have MS1extra up and running on my `82 528e. I am wondering about the difference between simultaneous and alternating squirts. I noticed in the MS docs it says that firing all injectors simultaneously can drop pressure in the rail. Has anyone had problems with this on an e28? I am using stock injectors so maybe it is a non-issue.

[abdielhiram]

This thread have make me happy, since I have been having problems with the B9...

Of course the car will loose its "originality" but I am going MS fter my ECU died, and I can wait to see that beast running again...

Thanks for this read, was worth every minute...

[9mil]

So I have been working on getting my MS box going in my e24 and I figured as I searched for all this stuff, I would diagram and try to add to the library while trying to get some questions answered. I think I have an okay grip on what needs to happen, but I am one of those that like things to be really clear before I turn the key. BTW – the car has run (but only for heat cycling and around the block to make sure it didn’t blow up!- no boost) with a TCD 059 Chip and Begi with 24lbs injectors. So I know it will run-

What I’m dealing with here:
1987 635CSI 5spd with 059 ECU and stock harness
*1985 M106 complete engine- rebuilt from crank up. Stk cam, headgasket and bolts- nothing too crazy
*Intake: open air element with 3in tubing to stock K27 (will be upgrading to the TCD built version when I prove this thing will run), FMIC with 2.5in piping with HKS SSQV BOV venting to atmosphere, Stock throttle body in the stock position.
*Stock M106 manifold with stock K27, TIal 38mm Waste Gate with 7lb spring venting to atmosphere currently, custom 3in exhaust with magnaflow muffler (no cats or resonators currently)
*Innovative LC-1 Wideband, boost gauge and KnockSense using stock M106 knock sensors only using for LED mounted on dash.
*Stock ignition, coil and wires (I own an MSD-6a and Blaster Coil that I have not installed yet to keep things simple)
*Walbro 255LPH inline replacement pump
*Stock FPR – I have a BEGI that I can use if the need arises –just trying to keep it simple currently.
*30lb HI injectors- Bosch 0-280-150-934

Concerning MS:
*Symtech rebuilt V3.0 running MS1 – I had them upgrade the Fiddle Circuit to accommodate the 3 wire Bosch ICV and add boost control circuit for future use (not looking to utilize that currently – just getting it going)
*E34 60/2 trigger wheel, VR Mount and VR sensor plugged into the existing harness (using stock harness and grabbing signal from ECU plug )
*TPS -STOCK 3 wire - This is where I start to stray as I only need 3 wires- and I am sorting this our currently as I know most use the multiple output e34 automatic plug for the additional wire.. but don’t you just need 5V to the unit, the potentiometer (off idle to WOT) and closed? I know there was a recent thread on this and I am sure I can find it and post the reference to it here for future info seekers.
*IAT - Open Element GM mounted relatively near the throttle body before the ICV entry. (EXTERIOR OF STOCK HARNESS)
*CTS – Stock coolant temp sensor, again using stock harness and grabbing signal from ECU plug

I was provided a baseline map when I purchased the unit from another member that had almost the exact setup- so the thought is, do some tweaking where I know the differences are and let Tuner Studio do the rest.



And just for ease of finding info- a repost from the first page-




Onto the issues at hand…
1) I know there is a 55 Pin PnP board but this requires replacing the harness- just as much work when it comes down to it.

2) I have an 8 conductor to the Throttle Body areas where I will connect the IAT (and potentially the TPS and ICV on their own harness if needed) This is why PINs 6 an 22 are not used

3) I am assuming that PIN 35 (MS PIN 28) will be my power source and all that relay hoopla in all the other wiring diagrams will not be required- same with PIN 20 (MS PIN 37) for the fueling.

4) I have the stock E34 trigger plugged into the existing harness which should allow for PINs 25 and 26 to be the positive and negative connections ( slice MS shielded cable open to show white and black wire, shield and drain wire) Now shouldn’t this drain wire be grounded? Or does it matter as it is a short run

5) I have seen in photos , in my numerous searches on this, a resistor on one of these cables (or at least I think it was one of these) as you can see from the photo, I do not have any additional hardware installed on any of the circuits…. You can also see I need help soldering! – I have resoldered my worst connections pictured and will be covering each with heat shrink.

6) I will be taking all the grounds noted on the diagram and all grounds (8,9,10,11,19) and terminating them into a distribution block that will have a dedicated 12g cable back to engine ground (and location of my wide band ground)

7) I need to hook up Tach signal to PIN 35

8) Fiddle Upgrade for ICV- I need to figure this out

9) I have been playing with my JimStim and TS to try to figure a little of this out and have somesort of idea which way to go when crisis is found.

On another note- Through SymTech (which by the way, was way above my expectations on any repair or service to my MS unit- I highly recommend them, great service and good pricing-) Recommended an offsite tuner to assist in initial startup, getting the thing to idle and just all around remote/ log in support. As I mentioned I have the baseline set up to start from- so at least I have that going for me.

I understand that I have a lot to learn concerning MS and I am trying to get it as best I can in a short amount of time. I am in the midst of taking on a new job, 7 and 1 year olds and all the other normal life issues that don’t allow any of us to spend the amount of hours necessary ALL at once to get this thing done. The motor, interior and suspension were all built 15 minutes at a time and I just want this thing to run- I’m tired of working without reward, so I apologize for the questions.

[TurboRichard]

After reading this post my first reaction is... NEVER IN A HUNDRED YEARS! I want to boost my 535is and I have most of the parts but I am not qualified to do this PERIOD.

So what do i do here? Find someone to tune this project? I think so. Build my own MS? Yikes I am just not qualified.

I would like to thank you for writing this because when I started i thought I would do this as a weekend project. But, you have completely chased me off from doing this project. I remember what my mechanic use to say when we raced across the country. "Well it may be broken today but you should have seen it yesterday!"

Any suggestions?

[Brad D.]

Richard,

It can seem a bit daunting at first, but there is plenty of support if you choose to go down that path. The largest key to a successful turbo system is the engine management. If it doesn't work right the car will never run right and reach its full potential. If you do choose to not try to tackle it yourself, you can contact Peter Florance and PFTuning and he can build you a plug n play MS unit and help you with your tune.

[Bungles27]

Hi people I have had a ms fitted to my car
today was the first time I have managed to check my map I wanted to put rhem on here for people to see and advice me where im going wrong the cat is running well bit uses a whole lot of fuel cruising I had fusion motorsport set up orihinally but im un happy with the map so want to have a go my self
here is a copy of my maps
https://db.tt/t2D8rFZ7 https://db.tt/7LftjATl https://db.tt/uDnYDsUv
My car is supercharged running 6psi and 30lb injectors any help will be greatly appreciated

[gazm3]

i have been thinking about putting on a megasquirt ECU on my M88/3 in E24. Im not really one for soldering computer stuff, but unsure if there is a plug and play setup. I know there is a P&P setup for the e30 chassis. Will this run open throttle bodies without the plenum?

[elcrazon]

Megasquirt has an Alpha-N mode that uses a throttle position sensor for load calculation and the newer firmwares seem to have an ITB mode but I'm not sure how it differs. You might try asking over on the msextra.com forums, or reading the docs there.

As for plug and play, all the boxes that drop in in place of the motronic ECU that I've seen use the 55 pin connector since those motors have the 60-2 crank wheel. Some people seems to have figured out how to use the speed and reference sensors in the bellhousing with megasquirt, but that seems to be more effort than just swapping the harness since it's much more well supported in the end.

[gazm3]

Megasquirt has an Alpha-N mode that uses a throttle position sensor for load calculation and the newer firmwares seem to have an ITB mode but I'm not sure how it differs. You might try asking over on the msextra.com forums, or reading the docs there.

As for plug and play, all the boxes that drop in in place of the motronic ECU that I've seen use the 55 pin connector since those motors have the 60-2 crank wheel. Some people seems to have figured out how to use the speed and reference sensors in the bellhousing with megasquirt, but that seems to be more effort than just swapping the harness since it's much more well supported in the end.

Cheers for this.

I have a euro M635csi, which I've been upgrading, now suspension, brakes, dogleg box, and 3.45:1 diff are all done, its time to get some modern drivablity out of the M88/3 with some headroom to upgrade in the future.

It seems the Megaquirt here is very popular and works well on the M30. The M88 is very similar in electronic architecture, but there seems to be a database of 0 when it comes to people talking about their Megasquirt upgrade - Hopefully that will change to 1.

I'm struggling to get a copy of the pinouts for the euro M635csi 055 Bosch ecu (mine is from 12/84). I managed to look at the 1987 M6 electronic troubleshooting manual, but its probably for the USA version Bosch 079, as it has a narrowband sensor, which I don't have, but the pinouts would be pretty close. I also cross refrerenced against the 1984 DME in a std 635csi, and aside from the barometric sensor in different location, the pinouts are the same.

It looks pretty basic, but as I have little experience with electronics construction, it would probably be wise for someone to build the Megasquirt. A chap called Peter Florence seems to come up here on this thread often, so this may be a good starting point, once I can confirm the pinout of the 055 DME.

Its running fairly sweetly on the standard computer (with Fritz Bitz chip) as I have a small device I can interrupt the fuel signal from the air meter, and alter it (with the help of the wideband sensor and A/F gauge), and upping the fuel pressure slightly and trimming the fuel out seems to add much needed timing, and has helped with dirvability and fuel economy enormously.

Still the airflow meter will act as a restriction, especially once I start playing with cams, and I will also have freedom upgrade or delete the intake plenum.

I may start a thread in the M5 section for the pinouts

[Jelmer538i]

I want to Microsquirt my S38B38 and a friend of mine is going to help me with this, he installed a Microsquirt last week on a Subaru Impreza turbo with succes. He also did my brothers S38B36 turbo (DTA Pro-8) and a lot of Megasquirts on various engines.

He asked me what kind of coils are used on my B38. He needs to know if the Microsquirt can drive them direct or if the need a resistor or somithing? (I not formiliar with this a all so It can e something elso to )

Also, does anyone know where I could find a base map from a S38/M88?

[mitch5]

so i just recieved my ms2 v3 and am stilling trying to decide what to do about the iacv, brad you should update the sticky because currently glensgarage is now a check/moneyorder only scam. I am trying to figure out where to buy an adapter board, i sent goathumper a pm but no reply. I have heard the other option is to find a 2 wire iacv. whats the best route for this?

[Brad D.]

so i just recieved my ms2 v3 and am stilling trying to decide what to do about the iacv, brad you should update the sticky because currently glensgarage is now a check/moneyorder only scam. I am trying to figure out where to buy an adapter board, i sent goathumper a pm but no reply. I have heard the other option is to find a 2 wire iacv. whats the best route for this?

It's a shame to hear that as it was a pretty sweet board that just worked and made waste spark really easy to wire up. It would be pretty easy to proto the circuit required, but I did find this as a modifiable "store bought" solution.

http://www.diyautotune.com/diysotm/zeal_3_wire_iac.html

[mitch5]

so i just recieved my ms2 v3 and am stilling trying to decide what to do about the iacv, brad you should update the sticky because currently glensgarage is now a check/moneyorder only scam. I am trying to figure out where to buy an adapter board, i sent goathumper a pm but no reply. I have heard the other option is to find a 2 wire iacv. whats the best route for this?

It's a shame to hear that as it was a pretty sweet board that just worked and made waste spark really easy to wire up. It would be pretty easy to proto the circuit required, but I did find this as a modifiable "store bought" solution.

http://www.diyautotune.com/diysotm/zeal_3_wire_iac.html

I have heard the proto area was a pain I'm the ass but I'll explore that option. Thanks for the link though that looks like a possible solution.

When I was reading through this thread though someone mentioned this http://www.diyautotune.com/catalog/pcbv ... p-134.html.
Is this a better option? Or will it work. Since the zeal motherboard is 35 bucks.