[Diy_efi] Why I asked about the GM V-6 MPFI

[Tomas J. Sokorai Sch.]

On Sunday 13 August 2006 08:27, Joe Boucher wrote:
> Engine timing.
>
> The MPFI system would require some kind of crank trigger.  The spacing of
> the disk slots on the crank could be copied on to a computer controlled,
> laser cut disk and the disk sandwiched between crank pulley and the
> harmonic balancer.  The BMW crank position sensing system (60 minus two
> knobs) is on the harmonic balancer and the bracket could be useable for
> mounting the GM sensor or maybe the BMW sensor would work.

Not necessarily, you can use distr. triggering too. 
On the older (batch fired injectors) GM MPFI the only difference between the 
DIS and HEI signals to/from the ECM are the 60 degree offset and that in the 
DIS, the coil dwell is handled on the ignition module. All this is possible 
to fix only fiddling with the software side of the setup.

I'm in the middle of the conversion of a '82 323i (M20 inline 6 engine too, 
but originally with K-jetronic mech. FI) to GM port fuel injection.

I used the following parts: 
- 1227727 ECM from a 3.1 V6 Turbo Grand Prix (I didn't want to get the cable 
salad into the car's interior, so I choose it for its weatherproofness).
- 2.8/3.1 DIS ignition (the one with the 6+1 pattern and only one sensor)
- $8D code from a V8 'vette, with HEI dist. triggering. (modified for DIS and 
6 cyl. of course ;) 
- Front vibration damper drilled to have the 6+1 GM DIS pattern
- Using the original TDC sensor ("OT-Geber" according to BMW German docs) on 
the damper as inductive sensor for the DIS ign, but "supercharged" with a 
stack of harddrive magnets to give a stronger signal.

I already did sucessfully run the engine with the DIS and ECM controlled 
ignition (mech. FI controlling fuel), and I'm now adapting the EFI manifold 
from your exact engine model to match my ports and I hope soon I'll be 
running full GM EFI and DIS ignition. 
... After that, "the voices" say something about forced induction too ;)

>
> The BMW uses a sensor on the differential which detects the pinion ring
> teeth.  I doubt the number of teeth will equal 2000 or 4000 pulses a mile.
> Some kind of converter circuit is possible, but I can't do that.

Lucky... I don't have that sensor, so I'm still trying to figure out where to 
get the VSS signal from.
On the other hand, my truck that I converted to EFI ('75 302 to GM TBI) runs 
great without VSS input.

>
>
> Knock sensing.
>
> BMW didn't start using knock sensors till 1991.  Mounting a GM knock sensor
> on the bimmer block might be a challenge.  I have a Bosch knock sensor off
> a Volvo, but am not sure it operates the same as a GM sensor.  I don't HAVE
> to have a knock sensor, but it sure would be nice.

Beware that these engines don't have hydraulic tappets/lifters, so the 
valvetrain is a bit noisy unless the valve lash is kept *very* well regulated 
all the time.
I don't plan running knock sensors (same with my truck).

-- 
Tomas J. Sokorai Sch.