BMW E36 m50b25 n/a

[z0tya]

engine config:
inline 6 24 valves
bore/stroke: 84/75 mm
comp ratio: 1:10
firing order: 1-5-3-6-2-4
ignition timing 6-12 deg at 700rpm *
fuel pressure: 3.3-3.7 (vacuum off) 2.8-3.2 (vacuum on) *
injector resistance: 15-18 ohm *
iat sensor: 2200-2700 ohm at 20C, 760-910 ohm at 50C *
iac valve: 20-25 ohm between p1-p2, 20-25 ohm between p2-p3 *
clt sensor: 2290-2700 ohm at 20C, 290-364 ohm at 80C *
crank sensor: vr, 400 ohm between p1-p2 *
cam sensor: vr, 800-1200 ohm between p1-p2 *



* from autodata

firmware version: 1.1.27 12x12

primary trigger:
60-2 vr



sec trigger:
not used



reference tooth table:



injection:
semi sequential



inj outputs:
  inj A ch1  (EC36P7)  for 1 cyl
  inj B ch2  (EC36P19) for 2 cyl
  inj C ch4  (EC36P8)  for 3 cyl
  inj D ch8  (EC36P20) for 4 cyl
  inj E ch16 (EC36P9)  for 5 cyl
  inj F ch32 (EC36P18) for 6 cyl




ignition:
wastedspark



ign outputs:
  2 (EC36P34) for 1 & 6 cyl
  3 (EC36P36) for 2 & 5 cyl
  6 (EC36P24) for 3 & 4 cyl



IAC controlling:
dual solenoid mode with pwm - trying use stepper A/B (max load 1 A)
with dual solenoid output, there is some restriction with the output selection. The 2 outputs must be neighbors like configure ign/6 and use ign/6 and ign/7 (the latter will be inverted)

[z0tya]

I am a bit confused with the inj/ign output...

h[2] is the ignition sequence lookup table going reverse order, last element is looked up first
so the 2:3:6:2:3:6 seems correct

h[0] is the injector lookup table going reverse order, last element -determined config.alternate- is looked up first
firing order: 1-5-3-6-2-4
which means injector sequence: 1-16-4-32-2-8
reversed : 8-2-32-4-16-1
how many times need transversed to get right firing angle?
at first I try twice: 16-1-8-2-32-4

h[1] is the reference tooth table
0-40-20-0-40-20 is good or 0-20-40-0-20-40 is the right values?

[gunni]

Are you running the COP´s?
If so you´ll have to setup dual out.

8 2 32 4 16 1

is going to be right for the injector sequence.

Reference tooth table is
0 40 20 0 40 20

But if it´s dual out , I believe it´s
0 40 20

[z0tya]

not cop, 6cyl wasted spark coil from edis so no need dual mode

[gunni]

Then the ign setup you had was right.

[z0tya]

thx!

What is the suggested iat and clt patch?
In a hungarian bmw forum guys say 1900,256.

Need flyback diode paralell the iac coils, or the stepper chip has it?

[gunni]

Run the IAC with IGBT´s or FET´s.
And use a diode on it , it should make it very stable.

I´ve always used 2025 or something like that on bmw´s. But you´ll have to verify though.

[z0tya]

really need to disconnect water hose to check timing?


brrrrr:)

Vems has only 4 igbt and I think one fet died....if the stepper can't handle the iac current, i need soldering...

[gunni]

It would have been best to order the vems with all igbt´s and fet´s.
As you most likely will always have something to use them for.

[z0tya]

I have made a helping draw to understand the trigger setup. Because of the tricky alignment of the trigger wheel, the real first trigger event is not the first cylinder tdc but the 2.nd 5.th pair.



From 1.1.x version vems uses the h[1] reference tooth array, shows which tooth to trigger from.
The h[1] correlate with h[2], so can be rotated together.

Both of the must read from the end, backward. And can be rotated together.

h[2]   2     6    3    2     6    3
h[1]   0   40   20    0   40   20
similar to:
h[2]   6    3    2     6     3    2
h[1]  40  20    0    40   20    0

where the ign outputs are:
  2 (EC36P34) for 1 & 6 cyl
  3 (EC36P36) for 2 & 5 cyl
  6 (EC36P24) for 3 & 4 cyl

The 2nd version is understandable better, and show how you hold the firing order, when you use the 2&5 cyl tdc to triggering.

(We need more than an hour to understand the working of this table without exact documentation....)

[GintsK]

really need to disconnect water hose to check timing?


brrrrr:)

Vems has only 4 igbt and I think one fet died....if the stepper can't handle the iac current, i need soldering...

I usually make own mark visible from right underside. Adopt indicator in spark plug hole is more easy than catch OE mark with timing light!

Gints

[SamSpade]

Good stuff in this thread. Pls keep 'em coming.

[multiplex]

looks like you are going to run in 'wasted spark' mode?  Are you still wiring all six coils to individual outputs?

I see you only called out 3 pins for your outputs.

If you really get stuck, let me know. I have my s52 running full sequential. I know how frustrating it can be

[z0tya]

no, i hate those coils:))
I am using good old edis 6 cyl wastedspark coil from ford scorpio cosworth 24v.
it is near bulletproof against the 6 individual coil, and good for more than 2 bar boost in forced imduction.
And I no need the sec trigger with this setup.

[z0tya]

Engine stall after open thottle - IAC config problem?

We did the setup for the engine, which start after some tune of afterstart enrichment because of the dense mixture. The idle is acceptable, but we have some problem with the bwm dual solenoid.
This is a half-open valve when unpowered, so when plugged off the rpm goes sky high. So for idle need about 40 value in reftable, and we must enable iac follow tps because withouth this engine often stall after small blip of the throttle.
This is the last setup:




After tuned VE table the avability to stall after open throttle remains, so I need some help if anybody has experience with this iac valve.




(I prefered the manual idle set with extra air pipe or with throttle open screw, and vems iac control for crank, warmup and extra load, but this engine stall without idle control)