[Gmecm] Jetronic

[bcroe at juno.com]

That system is only somewhat different than the 76-79 
Cadillac injection system.  Analog computer and all, 
but they did replace the points with reed switches.  The 
switches work fine, but sometimes the magnets come 
off the HEI shaft.  

My 79 Eldo and many other Cadillacs are using this 
system today.  I do some repairs on the ECUs for owners 
around the world.  Peak and hold port injection, ahead 
of its time.  Now they use "learning" ECUs and feedback 
to compensate for the poorer accuracy of saturated 
injectors.  At my house, I'm trying to marry a modern 
sequential injection, closed loop ECU to the original 
fuel handling components on Olds 350/403, and Cad 
425/472/500.  I have an ACCEL VII working.  

Bruce Roe


27 Feb 2006  "David Allen" <davida1 at hiwaay.net> writes:
>   Anyone remember the old D-Jet system?  It was the grandfather of our
> modern speed-density systems.  Had a fascinating magnetic / 
> mechanical
> pressure transducer for measuring density; and sets (yes- setS) of 
> breaker
> points (early version) for the speed sensor! Electronic ignition, 
> but points
> for the EFI... Leave it to Bosch!    The throttle switch would pulse 
> on and
> off as the throttle moved open and create extra injector pulses for
> pumpshot.   The ECU was fully analog.  There ARE people who re-map 
> these
> units by changing resistors, etc.
>   I saw one of these on an older Mercedes V8. It was an early 70's 
> model
> IIRC.   I'm not the type to scrap a unique system like this if there 
> is any
> hope.  I would try to repair if feasible, but if not, it would sure 
> be
> tempting to install a Delco 1226869 (or similar).  The distributor 
> had a VR
> pickup directly compatible with an HEI ignition module. You could 
> hull out
> the transducer, and there might be enough room inside to "hide" a 
> modern
> Delco MAP sensor.  The injector impenence would be an unknown, as 
> would be
> mounting the TPS.  After taking the time to develop a good 
> calibration;
> you'd have quite a system.  It would appear to be original, but with 
> the
> advantage of fully mapped fuel and ignition.
>   Fun to think about anyway!
> David