EFI control units

[Michael D. Porter]

Orin Harding wrote:
> 
> Mike,
> I have been using the TEC II made by Electromotive on my '79 MGB and it 
>works well. This ECU provides not only fueling control but also direct 
>ignition control.  The coils are supplied with the ECU and you do away 
>with all of your old distributor, etc. The biggest drawback to this unit
>is it's cost. Basic ECU for 6 cyl, with no sensors, is $1030.00 and the
>software another $300 to $500 depending on which version you get.  To 
>use a MAF sensor you'll need the $500 version.  Sequential injection is 
>available for an additional $250.
> I'm a bit confused--I received literature from Electromotive about three 
months ago on precisely the unit you describe, and there was no mention 
whatsoever of sequential injection, and, to boot, the schematic included 
clearly showed what I generically describe as L-Jetronic injector wiring 
(two injector pulse lines from the ECU, each feeding three injectors, and 
then spliced together to pulse all injectors once a rev).  I did very 
much like the integrated crank-fired ignition (and the ability to do even 
rudimentary curve-mapping on the basic unit is helpful), and thought 
(except for the price) that it was altogether pretty slick.  But the 
planned duration and overlap is just to enough to require (I think) 
sequential, and assumed from the literature that it wasn't available, so 
I just kept on looking.  How recently did you buy the unit you're now 
using?   

> I have tried both MAF and MAP and found that MAP was a lot easier to 
>install and get running OK.  You'll find that MAF sensing adds to the 
>overall system hardware complexity especially the intake.  You have to be very careful not to have any air leaks at any point after the MAF 
sensor with straight runs of pipe upstream and downstream of the sensor. 
As I said, MAP is a lot easier.
>The decision of MAF in favor of MAP is based mostly on reading incidental 
articles which suggested that MAP has some of the behavioral 
characteristics of carburetors, in that it can be fooled at some 
combinations of gas speed and inlet air density.  My general neighborhood 
has an altitude range of about 9-10,000 ft in a three-hundred mile 
radius, and after driving a few domestic rental cars which had the check 
engine light dancing on and off up and down hills, and listening to 
people complain about how often the MAP sensor failed, I thought it best 
to put up with the additional design difficulties.  

I am aware of some of the difficulties of getting proper air flow through 
the sensor--Donaldson came up with a particulate trap system for diesel 
engines which used, in part, a Ford MAF sensor, and we did have a time 
translating the requirements of that sensor to the production line.  Once 
the optimum position was found, we had to mark all the boots and pipes 
with witness lines so that each bus would go together reliably.  
> If you're not in a hurry, I've found a unit in England, currently under
> development,  that should sell for about $1000 and will have the same 
>features as the TEC II plus adaptive fuel control.  I'll be seeing the 
>manufacturer next month and hope to bring a unit back with me then.  
>I'll post a note here regarding the unit.
>Thanks, Orin.  In truth, I feel in a desperate hurry, but the reality is otherwise; the cars are in storage until I get a shop built, and I'm 
right in the middle of remodeling the house, as well.  Soooo, practical 
wisdom tells me I've got a bit of time yet. <g>  I've just been doing 
what I can to finalize all the bits and pieces of the system so it will 
work together properly.
Cheers.