Re: <tech> question about L-jetronic F.I.

[Tom Van Gunten <tomark@xxxxxxxxxx>]

Some body out there wrot a long explanation about why the tack did not work
with the MSD box with out that special part.

Since the brain gets it's signal from the distro/coil, I think, the MSD box
would give it a series "triggers" and none strong enough to actually be
picked up by the tach or the brain.

Hence the reason for the additional part. 

I know it was a while ago that the thread appeared, but it was a good
explaination of exactly what William's problem is (the immediate problem,
that is)

Who was the author of that post???

Other than the cold start injector, he has everything except gas from the
injectors.


Tom


At 08:09 PM 8/9/98 -0400, William Gau wrote:
>Alright, a question for the masses:
>
>I did a retro-installation of an FI system (vintage L-jetronic from a
>`76 3.0 Si into a `73 Bavaria) and am having a few unexpected problems.
>
>First off:
>
>  1) I have a positive fuel flow to the engine;
>
>  2) I have lots and lots and lots of spark and an ignition that is working;
>
>  3) The cold start injector is emitting an impressive conical mist in the
>right place :^)
>
>  4) Not a damn thing is happening (i.e., the engine is not coughing,
>sputtering, etc):
>
>The engine is a 3.3 bored to 3.46.  The only thing that me and my crack
>team of 
>technicians can figure out is the following:
>
>The ignition system is a new Mallory MSD 6A box, one of those BLASTER
>coils, and
>a mallory distro.  Somewhere buried in the Mallory propoganda is the
>following blurb:
>
>   "Some of the import vehicles are equipped with factory electronic fuel
>injection.
>  The EFI system requires a signal to synchronize the rate of fuel delivery
>to the engine
>  speed.  The EFI system control needs a signal very much like teh signal
>needed by a
>  tachometer.
>   "On most installations with EFI or with an electric fuel pump, an MSD
>P/N 8910 tach
>  adaptor will restore the system back to normal.  Blah blah blah"
>
>Obviously, the L-jetronic has an FI system that is controlled by the
>omnicient brain
>known as the "control module".  The control module gets all of it's info
>about what the
>holy hell the engine is doing from the coil.  What is it looking for is a
>weak signal
>usually generated by the stock points ignition.  What is is getting is the
>20,000 volt
>jolt-o-rama from the MSD box.  As a result (we speculate) it will not start.
>
>Has anyone used one of these MSD adaptors to cure an EFI compatibility woe?
>
>Someone write back while I finish putting trim on this car.
>
>Scrambling to make O'fest . . . .
>
>William Gau
>
>

------------------------------

End of bmw-digest V9 #43
************************