E28 Megasquirt FAQ

Discussion pertaining to positive pressure E28s.
Owndapwn
Posts: 486
Joined: May 18, 2014 12:22 PM
Location: Kansas City, MO

Re: Crank Trigger Wiring

Post by Owndapwn »

BuzzBomb wrote:What do people do to add the shielded cable from the b35 crank sensor into a from scratch harness? Do people cut the cable before the large plug at the original location b35 injector box and add it to the new harness at that point, or is the large plug connection kept and the shielded cable pulled from the b35 up to the dme plug? I guess the question is, should the ability to unplug the sensor be kept or gotten rid of for a cleaner install? How important is keeping the shield on the cable all the way to the relay board?
Shielding is VERY important in an area that's exposed to the elements, or exposed to heat. Personally, I would (And will) heatshrink the bundle (Medium sized pack of assorted heat shrink is like $3 at Harbor Freight), and then put a nylon shielding sleeve over that. I intend to do this to the bulk of my harness when I have the motor out and can get to it all, as it really makes a difference long-term.
Unless you're talking about a heat shield type thing on the actual plug end, in which case, I couldn't tell you. But the wires themselves should be shielded if it's even remotely feasible to do so.
BuzzBomb
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Location: SoCal

Re: Crank Trigger Wiring

Post by BuzzBomb »

Owndapwn wrote:
BuzzBomb wrote:What do people do to add the shielded cable from the b35 crank sensor into a from scratch harness? Do people cut the cable before the large plug at the original location b35 injector box and add it to the new harness at that point, or is the large plug connection kept and the shielded cable pulled from the b35 up to the dme plug? I guess the question is, should the ability to unplug the sensor be kept or gotten rid of for a cleaner install? How important is keeping the shield on the cable all the way to the relay board?
Shielding is VERY important in an area that's exposed to the elements, or exposed to heat. Personally, I would (And will) heatshrink the bundle (Medium sized pack of assorted heat shrink is like $3 at Harbor Freight), and then put a nylon shielding sleeve over that. I intend to do this to the bulk of my harness when I have the motor out and can get to it all, as it really makes a difference long-term.
Unless you're talking about a heat shield type thing on the actual plug end, in which case, I couldn't tell you. But the wires themselves should be shielded if it's even remotely feasible to do so.
The shielding I'm referring to is electrical, to shield the wiring from interference. It is the third "wire" that is a woven steel mesh surrounding the other two wires inside the insulation. Kind of like coax cable.
Owndapwn
Posts: 486
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Location: Kansas City, MO

Re: E28 Megasquirt FAQ

Post by Owndapwn »

Has anyone got a hold of an MS3 yet? I was looking at the documentation for it, and it doesn't look like you'd need any sort of adapter for the Idle Air Control, Glen's Garage or otherwise.
It looks like, without having tried it or talked to anyone who has, all you would need is the MS3, trigger wheel, TPS, and IAT.
BuzzBomb
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Location: SoCal

Re: E28 Megasquirt FAQ

Post by BuzzBomb »

Owndapwn wrote:Has anyone got a hold of an MS3 yet? I was looking at the documentation for it, and it doesn't look like you'd need any sort of adapter for the Idle Air Control, Glen's Garage or otherwise.
It looks like, without having tried it or talked to anyone who has, all you would need is the MS3, trigger wheel, TPS, and IAT.
It's the same as MSII, except that the circuit for the 3 wire IAC valve is now native. The external connections are all the same as before.
Owndapwn
Posts: 486
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Location: Kansas City, MO

Re: E28 Megasquirt FAQ

Post by Owndapwn »

BuzzBomb wrote:
Owndapwn wrote:Has anyone got a hold of an MS3 yet? I was looking at the documentation for it, and it doesn't look like you'd need any sort of adapter for the Idle Air Control, Glen's Garage or otherwise.
It looks like, without having tried it or talked to anyone who has, all you would need is the MS3, trigger wheel, TPS, and IAT.
It's the same as MSII, except that the circuit for the 3 wire IAC valve is now native. The external connections are all the same as before.
So it does bypass the need for a GG IAC board? 'Cause that offsets the price difference, IMO.
BuzzBomb
Posts: 1659
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Location: SoCal

Re: E28 Megasquirt FAQ

Post by BuzzBomb »

Owndapwn wrote:
So it does bypass the need for a GG IAC board? 'Cause that offsets the price difference, IMO.
Since GG isn't a reputable seller by any stretch of the imagination, I'd say it more than offsets the difference, if only the PITA factor of dealing with him.
87M6chris
Posts: 21
Joined: Oct 26, 2007 7:51 PM
Location: Toronto,Ont.

Re: E28 Megasquirt FAQ

Post by 87M6chris »

Hi all, this is a great thread, have learned a lot reading it. I can't get my stock ECU working anymore so have decided to move to a MS system, I'm starting to collect stuff I need and just bought the 60-2 harmonic damper, crank sensor and sensor mount from a m30b35 engine. I mounted it up on the s38 but the sensor is not perfectly centered on the toothed wheel, how crucial is this alignment? I can shave the difference off of the sensor mount feet but not sure if this is built in deliberately or if I should adjust it.
Thanks for any advice you can give me,
Chris
[img][IMG]http://i682.photobucket.com/albums/vv185/87M6chris/DSCN0200.jpg[/img][/img]
[img][IMG]http://i682.photobucket.com/albums/vv185/87M6chris/DSCN0198.jpg[/img][/img]
Kyle in NO
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Location: Nasty Orleans------> Batten-Rooehjch------>More Souther LA

Re: E28 Megasquirt FAQ

Post by Kyle in NO »

Chris, that alignment is totally fine. I'd not mess with it.
87M6chris
Posts: 21
Joined: Oct 26, 2007 7:51 PM
Location: Toronto,Ont.

Re: E28 Megasquirt FAQ

Post by 87M6chris »

Thanks Kyle,

Now that I'm installing MS I realized that I can get rid of the low impedance fuel injectors and enjoy the better selection of high impedance injectors and simpler set up over all.
The s38b35 engine uses a 24lb injector that just barley covers the HP of the stock engine so I'm looking at these,
https://www.fiveomotorsport.com/30lb-02 ... evil-bosch
they are 30lb which will allow me to push the engine to the 280 hp range.
The MS manual warns about not using too large of an injector because of possible idle problems but it doesn't say how much is too much.
Does the jump from 24lb to 30lb seem like too much or is the manual referring a much larger injector jump?
Thanks,
Chris
tschultz
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Re: E28 Megasquirt FAQ

Post by tschultz »

No, you will be fine.^^

It is talking about 60+ lb injectors
Owndapwn
Posts: 486
Joined: May 18, 2014 12:22 PM
Location: Kansas City, MO

Re: E28 Megasquirt FAQ

Post by Owndapwn »

Target should be between 50% and 80% max duty cycle on the injector at full load.
70-80% is ideal if you're done, but if you plan on tweaking it and making more power, as little as 50% will have no issues, and still give you tons of room to move.
87M6chris
Posts: 21
Joined: Oct 26, 2007 7:51 PM
Location: Toronto,Ont.

Re: E28 Megasquirt FAQ

Post by 87M6chris »

Thanks guys, that makes sense. The new injectors arrived from FiveO and the whole Megasquirt kit.
I'm wiring the relay board for the test stand, and the version I have MS2 357-C says it can handle our Bosch idle control valves without modifing the MS, PWM idle valve or Fidle, it says to run the middle Grn/Pur power wire from the ICV with fuel pump for power and run the negative wire from the ICV to the #6 Fidle terminal.
But our Bosch ICV have 3 wires, 1 power, 1 open, 1 closed, not sure how either open or closed could be considered negative?
[img][IMG]http://i682.photobucket.com/albums/vv185/87M6chris/DSCN0246.jpg[/img][/img]
87M6chris
Posts: 21
Joined: Oct 26, 2007 7:51 PM
Location: Toronto,Ont.

Re: E28 Megasquirt FAQ

Post by 87M6chris »

Got an answer from Matt Cramer at DIYAutotune, "Run the "close" wire on the IAC valve to ground through a 10 ohm, 25 to 50 watt resistor." and I assume the open wire goes to #6 Fidle on the relay board and the power wire can double up with the fuel pump power wire.
87M6chris
Posts: 21
Joined: Oct 26, 2007 7:51 PM
Location: Toronto,Ont.

Re: E28 Megasquirt FAQ

Post by 87M6chris »

I would be asking these MS questions on the MS forum if they would approve me, I tried to register over 3 wks ago and haven't heard anything from the yet.

Okay, so I have ironed out almost all the little problems and I'm very close to trying to start the engine for the first time, I have successfully done the fuel pump test, injector test, ICV test, still not sure if the coil test was right or not, I didn't hear any snapping of spark but the plugs are about 8" inside the engine. I will have to pull them and try that test again.
The thing that has me stumped is in the Diagnostics & High Speed Loggers section, can't get anything to show up on the screen when cranking the engine in Composite logger, tooth logger or sync error logger.
I tested the magnetic sensor with a volt meter and am getting 3-7 mv on a cranking engine, I have tried switching the wires from the crank sensor with no change in results.
Sort of dead in the water at the moment, any advice would be appreciated.
Thanks,
Chris
smhheidari
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Joined: Aug 01, 2012 2:07 PM
Location: Rockville, MD

Re: E28 Megasquirt FAQ

Post by smhheidari »

downforce22
Posts: 65
Joined: Apr 06, 2015 9:24 PM
Location: colorado springs

Re: E28 Megasquirt FAQ

Post by downforce22 »

the tooth #1 angle on the diy website is wrong for the m20. I think i'm running either 84, same as this e30 zone website. Whats the angle for the m30? http://www.e30zone.net/e30zonewiki/inde ... g_Your_M20
tschultz
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Re: E28 Megasquirt FAQ

Post by tschultz »

Since the FAQ images aren't working, I figured I'd link a website that stole the content:
E28 Megasquirt FAQ



Compliments of Brad D. @ http://www.mye28.com


E28 Megasquirt FAQ
By Bradley Denton
Revised 01/06/10

Since there is a lot of interest in Megasquirt as well as a lot of people on this board either using MS or planning to, I felt that I would try to help add to the knowledge base. I don't know if the FI forum is the best place for this, but felt that since most of the MS users are FI guys as well, it was fitting. I am hoping this can be stickied as well, in whatever forum the Beamters deem appropriate. I hope as much of this information is as correct as possible, but I am human and occasionally make mistakes. If anyone has any questions, comments or corrections, please feel free to contact me. Enjoy!

What is Megasquirt?

Megasquirt (MS) is a DIY programmable standalone electronic fuel injection (EFI) computer. It performs many of the same functions as the factory Motronic unit in the e28 but allows the end user to adjust different parameters (fuel, timing, idle speed, etc) affecting how the engine runs. Since it is DIY, it is much less expensive than many other standalone ecus or even some piggyback computers. Megasquirt can be used to control fuel only or both fuel and spark. It is my opinion that for an e28 application you want to control both fuel and spark. It is also an excellent learning tool to understand how EFI works while making your car run better. You can read more about Megasquirt here. The user forums can be found here.

Why would I want to run Megasquirt on my e28?

The stock Bosch Motronic system in your e28 works well for a car in stock form. If many modifications are made to the car such as a large cam, high compression and headwork, or by adding forced induction (turbo or supercharger), or even a stock engine and you want to optimize things yourself instead of just installing a chip, fuel and timing maps will need to be modified for optimum performance. The stock Motronic can only be adjusted by altering the programming on the “chip” in the ecu. This is not the easiest way to tune your engine. You are also still left with the outdated architecture of the original Motronic system whose primary load input is a vane style air flow meter (AFM). By replacing Motronic with a MS unit you can now adjust fuel and timing maps, datalog, adjust your rev limiter, change idle speed, control electric fans, if you can think of it, MS can probably do it. Just plug in your laptop to MS, make your changes, save your tune, and you are good to go!
https://www.diyauto.com/manufacturers/b ... -by-brad-d
tcturbo91
Posts: 129
Joined: May 11, 2011 8:39 PM
Location: Delaware

Re: E28 Megasquirt FAQ

Post by tcturbo91 »

I figure I would post here before making a new thread, I am currently running the Miller War Chip/MAF conversion for tuning on my M30 turbo project. I have had the car together for over two years now and with on and off tuning issues i'm ready to ditch it for Megasquirt. I'm looking for someone to build me a setup, was wondering if anyone on here still does this or can point me in the direction as to who would be a good person to enlist for a build. thanks!
Owndapwn
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Joined: May 18, 2014 12:22 PM
Location: Kansas City, MO

Re: E28 Megasquirt FAQ

Post by Owndapwn »

Has anyone done a full MS3+ install and thought to document some differences yet?
1986series6
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Location: West Nyack NY

Re: E28 Megasquirt FAQ

Post by 1986series6 »

Shawn D.
Beamter
Beamter
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Re: E28 Megasquirt FAQ

Post by Shawn D. »

What's the point of your post? Mark D'Sylva makes great chips (I have one for my stock ECU and recommend them above all others), but he doesn't do anything for MegaSquirt. The tuner you linked to doesn't mention MS, and this is not a "tuner" thread anyhow.
Owndapwn
Posts: 486
Joined: May 18, 2014 12:22 PM
Location: Kansas City, MO

Re: E28 Megasquirt FAQ

Post by Owndapwn »

Mark's chips don't allow you to run launch control on a turbo car, so I'm not sure how you think the two are interchangeable while still assuming you know what an ECU actually does.
Ju@n
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Re: E28 Megasquirt FAQ

Post by Ju@n »

Owndapwn wrote:Has anyone done a full MS3+ install and thought to document some differences yet?
Late to the party, but yes, I have.
Only difference is since I have the MS3X board, I used the 3 pin ICV option on the software and used Idle and VVT pins on MS3X board instead of Fidle and resistor to ground as seen on MS2 installs. Works alright :D
The rest is mainly the same, going to install 6 LS2 truck coils as well as a distributor cover plate with a VR sensor later this year and create a custom wiring harness (instead of using the M1.3 one) so I can get Fully sequential injection and ignition.
Owndapwn
Posts: 486
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Location: Kansas City, MO

Re: E28 Megasquirt FAQ

Post by Owndapwn »

Ju@n wrote:and create a custom wiring harness (instead of using the M1.3 one) so I can get Fully sequential injection and ignition.
Be sure to document your harness plans for us!
turbodan
Posts: 8801
Joined: Jan 09, 2007 10:19 PM

Re: E28 Megasquirt FAQ

Post by turbodan »

I'm surprised to return to Megasquirt so many years later to find that my old settings don't seem to work well at all. Cranking pulsewidths on the current install are vastly different than before. Same engine configuration, may be differences in firmware. Who knows.

This time of year is the ideal opportunity to test cold starts. My old settings were far leaner than before, the new settings are as follows:

Cranking Pulsewidth %
Degrees F Pulsewidth %
-20 400
30 270
50 232
70 203
100 168
120 148
140 138
165 132
180 130
200 128

Afterstart Enrichment %
-20 47
30 35
50 30
70 25
100 18
120 13
140 9
165 5
180 3
200 2

Warmup Enrichment %
0 197
30 176
50 156
70 138
100 125
120 117
140 112
165 105
180 103
200 100

It started great at 33.5 degrees this morning. Tomorrow should be in the 17 degree range, that will be very interesting. The best cold start this thing ever did was with 24 degrees showing on coolant temp, which wasn't exactly perfect but it did light off with a reasonable cranking period and stabilize without sputtering out.

One setting I found that helped was to run the ICV before engine start, one of those things Motronic does that is easy to overlook. I think this setting may default to off in Megasquirt so it's one of those sneaky ones that has a subtle but negative effect. Having this "off" causes the manifold pressure to drop significantly when cranking begins but before the engine really lights off. Keeping MAP up near atmospheric increases cranking pressure and helps heat and vaporize cold fuel.

Warm starts are still perplexing, it seems to crank too long but only by a few tenths of a second. I was running much leaner settings, today I bumped the percentages up quite a bit. Will have to do some more warm starts to see how it responds. Ideally the car should sit for 15-20 minutes to allow any pooled fuel to cook away and dissipate. Restarting immediately after shutdown isn't nearly as common as restarting after 15-30 minutes of sitting while you're in the store for pretzels and beer.

As it is now the car runs great, way better than Motronic. No more weird idle behavior, no more odd driveability quirks. It's running the narrowband O2 feedback for fuel trims, saving me some gas. The car is ready for boost as soon as I get the turbodiesel manifold properly notched and build my intake plumbing. Even if I left it NA it would have been worth it, it's got more meat to the power. Motronic always felt to me like the power was flat, with some ebb and flow to the delivery. Same story with my last three or four e28's. Megasquirt with a proper fuel and ignition map delivers a power curve. The 528e now has a distinctive hit at 3000 RPM, feels like the M20B25 but it comes on and signs off about 1000 RPM sooner. Low end power is strong and smooth, throttle response is consistent and excellent.

Last time around I gave up on EAE. Didn't feel a need for it and I never could get it working properly. This time I'm running it full time. The current code allows both EAE and traditional AE simultaneously. EAE doesn't have to be perfect with the conventional AE online for quick throttle movements. They complement each other and EAE is always working during the kind of transitional throttle movements it sees constantly during normal driving. It's pulling back upwards of 20% of the fuel on throttle lifts to help maintain a reasonable AFR. Saves gas, less stink for the cars behind you. What's not to like.
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