E28 Megasquirt FAQ

[alijonny]

I swear to god, if I come out of this alive I will be a better man.

[George]

I've posted a pdf of my power point notes from the MegaMeeting 2009

http://www.pftuning.com/megasquirt/Mega ... d_2009.pdf

Peter, your the MAN!

[alijonny]

hey, quick question, I am not able to access the AFR table for some reason. Any idea on why I cannot click on the AFR table to set it up? Thanks!

[George]

hey, quick question, I am not able to access the AFR table for some reason. Any idea on why I cannot click on the AFR table to set it up? Thanks!

Do you have your O2 sensor type selected?

[alijonny]

you know, I was thinking about that, I have the summit racing brand wideband o2 setup (which says innovate motorsports on it), i see there are different options for the WB. let me see...

[alijonny]

went to EGO controls and setup for WB. AFR table is now available. are there any special settings i should use, or are the default settings ( on temp, kpa, igntion events, etc...)

[alijonny]

From Megtune setting of constants:
I have my setup as 6 cyl, is that right? I don't understand this.
Number of Cylinders
... This value is actually the number if ignition events per cycle sent to the ignition input on the controller (so my initial Audi installation, which took the ignition signal from a single-window Hall sensor in the distributor, was set up as a 1-cylinder motor rather than a 5-cylinder).

[Brad D.]

Hopefully this will help. Remember, the ReqFuel value is an injector scaling constant. Unless you are using the same size injectors as me (42lb/hr), your value will be different. Just use the calculator if you are unsure.

[alijonny]

Hopefully this will help. Remember, the ReqFuel value is an injector scaling constant. Unless you are using the same size injectors as me (42lb/hr), your value will be different. Just use the calculator if you are unsure.

yep that damn near the same as what I have. I think my req fuel is 9.2 if not mistaken.

[alijonny]

I got the car running (woo hoo!) with the grey connector from the b34 harness to the b35 vr sensor (plugged right in to the b35 black connector). I thought this was not possible...

however, cylinders 1, 2, and 3 are dumping fuel like crazy. If I unplug the injectors on the front cylinders, the car will run on the rear 3 cylinders. I checked my wiring and everything looks right. the car idles and the IACV seems to be functioning properly.


am I supposed to combine both b34 crank ref sensors for all cylinders to fire? any ideas on the dumping fuel part?

edited for my mistake with cylinder placement...

[mooseheadm5]

Sounds like one injector driver may be bad or your wiring may be bad. You do not combine crank position signals. One sensor is all you need.

[alijonny]

hmmm bad injector driver? I checked to make sure my wiring was good, and all seems right...
I want to make sure of the problem tomorrow, because the first 3 cyl flooded big time because the prime pulse was set at like 5 seconds and I primed the car a few times. rear 3 cyl had no fuel smell when I pulled the plugs and were dry. the front were wet and when I cranked the engine with no plugs ALOT of fuel came out (glad I didn't hydro-lock it) there was a lso a lot of fuel accumulated in the manifold and wastegate area.

I verified that I was getting spark at the first three cylinders and it looked good. Maybe I will try to swap plugs front to rear and see how it runs.
I'm also gonna hook up a noid light tomorrow and see exactly what is going on with the first 3.

[mooseheadm5]

Yep, a noid light will tell you if it is hanging the injectors wide open. Also read this in the presentation referenced earlier:

Can't tune idle – works ok during load.
• PWM TIP125 shorted on one bank causing longer
closing times

[Brad D.]

Be aware that the way that MS batches the injectors are 1,2,3 and 4,5,6. It is odd that you are having issues with with alternating cylinders. I would confirm that you don't have a small wiring issue and that one batch of injectors isn't accidentally grounded causing them to be full open. Do you have any logs of this so you can see what both batches pulse widths are doing?

[mooseheadm5]

He used the stock wiring harness. Doesn't that batch the injectors even and odd?

[Brad D.]

Motronic 1.0 does 1,2,3/4,5,6 and Motronic 1.3 does 1,3,5/2,4,6. Megasquirt is anticipating it as 1,2,3 and 4,5,6. I had to rewuire my 1.3 harness accordingly. It will run though, just not as well. That should not be causing this gross overfueling problem though. It sounds like a batch of injectors is grounded all the time.

[alijonny]

yeah, I wonder if my db37 connector towards the engine got a wire touching another when I put it all together. That would be possible in my mind as the jimstim didn't show that as a problem through the ranges and especially idle. I looked at the pinout on the motronic case and everything there seems fine. with nothing touching

I wonder if it is a problem with the tps as well, as that is either wired incorrectly or has a short somewhere too. before I did the calibration, it was reading 100% with the tps at 0%. if I would open the TB, it would stay at 100%, even after calibrating it. If I would unplug the harness from the TPS the value would go down sloooowly and level out at about 50% until I would cycle the ignition.

I found this on an e30 site by googling BMW 6 pin tps and wired it according to this:

Ok, on the e34 m20 525i variable tps the
yellow wire is the signal out
the black wire is the 5 volt power
and the steel braided is the ground
so the yellow wire goes to the brown/blue wire on the stock tps
the black wire goes to the brown/black wire on the stock tps
and lastly the steel braided wire goes to the brown wire on the stock tps

[alijonny]

OH MY GOD. I just realized I was looking at the firing order to tell which cylinders are firing/not firing. I tell you, it's so easy to be stupid!

I'm sorry guys, it is cyl 1,2 and 3. Honestly, I do know what I'm doing...

[Brad D.]

So it sounds like you have your injectors batches correct. Now to confirm that one batch isn't grounded and staying open all the time.

[russc]

What, my M1.3 harness is still stock? So you have to re-wire. Will that help my crappy idle?

RussC

Motronic 1.0 does 1,2,3/4,5,6 and Motronic 1.3 does 1,3,5/2,4,6. Megasquirt is anticipating it as 1,2,3 and 4,5,6. I had to require my 1.3 harness accordingly. It will run though, just not as well. That should not be causing this gross overfueling problem though. It sounds like a batch of injectors is grounded all the time.

[Brad D.]

Absolutely it will. That is when it is most noticeable. There are several old discussions of it over on e30tech.

[Shadow]

Motronic 1.0 does 1,2,3/4,5,6 and Motronic 1.3 does 1,3,5/2,4,6. Megasquirt is anticipating it as 1,2,3 and 4,5,6. I had to rewuire my 1.3 harness accordingly. It will run though, just not as well. That should not be causing this gross overfueling problem though. It sounds like a batch of injectors is grounded all the time.

NO WAAAH!

Are you 100% on your info?
What changes have you noticed in the VE and
felt drivablitly/idle?

I have it wired like the 1.3 motronic, and runs pretty sweet
to me.

[alijonny]

brad, where did you get your pinout for the 35 pin motronic case? This must be why I have a problem as the pinout shows pins 15 and pin 16 are for the injectors and the bentley manual shows pin14 and 15 are for injectors on the 535i
someone verify this for me. It's still early for me.

[Brad D.]

Well, it looks like I made a mistake. I am terribly sorry for that. I never actually worked on a 35 pin unit and didn't catch that. I confirmed what you found and it IS pin 14( 1,2,3) and 15 (4,5,6). 16 is a ground which is probably why you are having a problem. I will revise the drawing ASAP to reflect this error. Again, sorry for any inconvenience it may have caused.

EDIT - The diagram is fixed to reflect the change in injector wiring.

[turbodan]

If you dont want to rewire your harness you can just run one squirt simultaneous injector staging. Works great.