[Diy_efi] Jetronic

Tue Feb 28 05:33:37 UTC 2006

Top reply: Oh man, David, you had to go mention Mercedes...and I happen to
have an early-70s twin-cam six 280CE Coupe sitting in my yard.  This has the
hot Euro cams, and IS injected.   Have had no reason to determine what type
of system it has since it runs like a watch - and there's no better sound
than a straight six with a split manifold - which this one has right from
the factory.   It has maybe 30K miles on a TOTAL powertrain rebuild - have
receipts an inch and a half thick to prove it.   The owner was going to
cherry it out, starting with with all of the above, then made the serious
mistake of loaning it to his daughter-in-law until she "got her act
together".  Duu-UUhh!  She dinged it on most corners, the interior is shot,
and he didn't have the time for it, so I picked it up - also awaiting a slot
on my calendar.   I run it regularly, keep fresh gas in it, what a gem.
Actually needs a home, if anyone's interested, contact me off-list.

Thanks for the early Fuel Injection history; like anything else we pretty
much take for granted, there's usually a LOT more to the story when those
who were there get to tell the story.

Ernie

----- Original Message -----
From: "David Allen" <davida1 at hiwaay.net>
To: <diy_efi at diy-efi.org>; "GM-ECM" <gmecm at diy-efi.org>
Sent: Monday, February 27, 2006 8:48 PM
Subject: Re: [Diy_efi] Jetronic

>   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
>
>
>
> ----- Original Message -----
> From: "Bill Washington" <bill.washington at nec.com.au>
> To: <diy_efi at diy-efi.org>
> Sent: Monday, February 27, 2006 5:11 PM
> Subject: [Diy_efi] Jetronic
>
>
> > One minor addition to Torbj?rn's information:
> > In the analog systems from mid 80s on there were also LE2 and LU2 - (LE
> refers
> > to European spec and LU refers to USA spec) and LE2 and LU2 both have
> closed
> > loop lambda control. The Bosch part number on my LE2 is 0 280 000 344.
> > For years I have been trying to obtain a circuit of the Pinted circuit
> board in
> > the ECU to repair, and modify a faulty one I have, but these schematic
> appear to
> > have been printed on a very rare material called 'unobtanium'.
> > These later LE2 Jetronic ECUs use a single printed circuit board with
> leaded
> > components on one side (including a couple of hybrid modules) and very
> dense
> > surface mount components on the other and a 25 pin connector to the
wiring
> loom.
> > I have found one early LE Jetronic ECU schematic for a BMW on the web
> > (0 280 001 310) but it is significantly different from my ECU, and is
> therefore
> > of little assistance....
> >
> > Regards
> > Bill
> >
> > >
> > > Subject:
> > > Re: [Diy_efi] Motronic hacking...
> > > From:
> > > Torbj?rn Forsman <torbjorn.forsman at gengas.nu>
> > > Date:
> > > Sun, 26 Feb 2006 23:55:41 +0100
> > > To:
> > > diy_efi at diy-efi.org
> > >
> > > To:
> > > diy_efi at diy-efi.org
> > >
> > >
> > > It is not very precise to call an injection system "Jetronic". This is
a
> > > brand name that Bosch uses for all systems that only deal with fuel
> > > injection, not ignition.
> > >
> > > Analog systems are D-jetronic (manufactured from about 1969 to 1974),
> > > L-jetronic (1974 to mid-80's), most LE-jetronic (1981 to early 90's)
and
> > > all LU-jetronic (the same as LE but with closed-loop lambda control).
> > >
> > > Digital systems are LH-jetronic (from early 80's to mid 90's, most of
> > > them but not all have closed-loop, LH 2.4 and later have adaptive
lambda
> > > correction and some diagnostic features), LE3-jetronic (the last
> > > non-closed loop system, the ecu is integrated in the air flow meter)
and
> > > Mono-jetronic (a TBI system, only used with closed-loop and adaptive
> > > lambda correction).
> > >
> > > The K-jetronic, an all-mechanical system should also be mentioned. It
> > > may have a closed-loop add-on and is then called K-lambda-jetronic. A
> > > similar but newer variant is called KE-jetronic, it exists both
without
> > > and with closed-loop. Most KE systems are analog but the KE3 is
digital
> > > (and then uses an ecu that is very similar to the Mono-jetronic ecu).
> > >
> > > Most digital Jetronic systems use an Intel MCS-51 CPU. Either a
standard
> > >  8051/8031 with a separate A/D converter, or an 80535/80C535. In some
> > > cases, mask programmed 8051's may be found but they more commonly have
> > > an external eprom. Anyway, all PCBs are designed for external eprom so
> > > it is a simple task to solder an eprom socket and the address latch in
> > > place, and change the jumper for the CPU's EA signal.
> > > The eprom may be socketed or soldered in place depending on
requirements
> > > from each car manufacturer.
> > >
> > > Some older LH-jetronic (in particular, LH 2.2) use instead an 8049 CPU
.
> > > The very earliest LH systems might have an RCA 1802, like the early
> > > Motronic systems.
> > >
> > > The simplest way to identify a Jetronic system is to look at the Bosch
> > > part number of the ECU.
> > > I.e. 0 280 000 561. The first six digits tell just that it is a
Jetronic
> > > CPU. The seventh digit indicates the number of cylinders, 0 means 4
> > > cylinders, 1 means 6 cylinders and 2 means 8 cylinders. The eighth
digit
> > > indicates the variant. 0 means D-jetronic, 1 and 2 means L-jetronic, 3
> > > means LE- and LU-jetronic, 5 and 9 means LH-jetronic, 7 means
> > > Mono-jetronic and 8 means K-lambda and KE. The two last digits are a
> > > leap number.
> > >
> > > So, when asking about a "Jetronic" system, be sure to include the
> > > variant of the system. I.e. mention that you have an LH 2.4 with
> > > closed-loop.
> > >
> > > Best regards
> > >
> > > Torbj?rn Forsman
> > >
> >
> > _______________________________________________
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> > Diy_efi at diy-efi.org
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> >
>
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