MegaSquirt Assistance: e34

[SoopaGhetto]

The megasquirt i built is supposed to be compatible with an e30 /e34.

purchased: http://www.diyautotune.com/catalog/d...kit-p-385.html

Followed these instructions / modified for wasted spark ( added 3 additional igniters): http://www.diyautotune.com/diypnp/do..._assembly.html

-No Variable TPS
-Added Innovate MTX-L wideband
-GM IAT
-Stock Coolant sensor
-Stock Injectors


First question: Are there any differences between the e30 / e34 dme pin outs? I've been under the assumption that they are the same from trollin the forums.

My issues: The megasquirt doesnt seem to be receiving power from the main relay (key turn to run does nothing). Once i apply an external power source (barrel jack) you can hear fuel pump relay clicking as well as priming injector clicks. ( works appropriately)

Seems like a dead ICV. I was able to figure out an issue with the 2500 rpm idle, but not sure what could be causing this problem (other than wiring at the unit) I taped up the intake boot with a small opening and was able to manually idle down to ~700rpm leaving me to believe the ICV isnt being actuated. Doesnt matter if plugged / unplugged -> same result

The IAT sensor functions properly (blowin my hot stank breath on it was able to make the temp rise and fall once cooled...BUT im hearin a relay click once the wire is disconnected / reconnected. (pin 1 & 4 on the AFM plug) WTF..

Car starts / runs perfectly with the megasquirt on external power plugged into the stock 55pin harness plug; Im going to be retracing the build, but since it runs fine with test, im not sure if construction and pinouts are wrong...

[Q5Quint]

Any luck fixing this yet?

If the e34 had a m20 in there it seems like there were two harness versions depending on what year m20 it came with (i think this wikipedia info is broken actually)



seems like pins 18 and 35 or 18 and 37 should be on with the ignition on.

EDIT: but I just realized I am a big dummy and looked at your photo again- that is a m30 isnt it?

[SoopaGhetto]

YES actually! I forgot to up date this thread!

I incorrectly soldered 4 connections. one ground, idle control close, relay out, and sg

I can confirm the e34 m30 DME having the same pin out as the e30 m20 DME (at least the 1990 e34). I made no other modifications and when i corrected the mistake, instant start up and badassness.

I really suck a searching hahahah i did not find those

[Q5Quint]

Excellent!

Here is another diagram if you want to be a wizard: http://www.armchair.mb.ca/~dave/BMW/e34/e34_92.pdf

[SoopaGhetto]

Thanks!

This question may have been answered already;

Im experiencing a slight idle surge. It's subtle but you can feel the feel the rpms rise and fall bouncing between 700-800; any recommended settings? Its not a big deal and as i start adjusting the warmup pwm i was able to smooth it out enough to where it is now.

Also, does the dme measure the injector duty to determine the instant mpg? i thought about building a circuit up to fix that...

[elcrazon]

There's this board for making the econometer work:
http://www.seattlecircuit.com/fuel_signal.htm

Not sure if they still do it, but the sites still up so you could try emailing them.

[ZenitramNaes]

I was just about to post a e34 megasquirt related thread, then saw this. Doesn't answer my questions, but I'm glad you got things figured out for the most part. One question for you is, where did you get the tune you are using? Are you using the old 2.2.1 tune that diyautotune provided? I would have told you to check my signature link to check out my MS build, but it looks you're experiencing problems I haven't got to yet.

Also, could you post some pictures up on how you wired up the MTX-L? Sounds like we have very similar setups.

Good luck! Let me know about that tune!

-Sean

[SoopaGhetto]

I am using firmware 3.3.1

I used all stock wiring. I can get better pictures of the specific wiring. BUT for the MTX-L, the black wire is signal on the stock o2 sensor plug. i could not get any power out of the white/white wires and grey is sensor ground.

I ended up wire-tapping for the gauge to turn on when the main relay is triggered. i can show in the later pictures (but you can see it in the last one if you look closely)

My goal is to boost this thing, either turbo or super charge. If that fails, im dropping in a v12...

[ZenitramNaes]

Oh, so did you just splice the wiring into the stock 02 harness? That actually makes a lot of sense, I've been wondering how I was going to connect the wideband to the MS for a while.
I've got a list of things to do this weekend in order for MS to run, and that's one of them.

[SoopaGhetto]

yeop! easier than adding more wires and crap.

[ZenitramNaes]

:up: Many thanks! Hopefully I'l make some progress this weekend.

[ZenitramNaes]

Any thing you want to update us on? Also I'm curious how the wasted spark is working out for you.