[Diy_efi] Motronic hacking...

[Torbjörn Forsman]

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


David Allen wrote:
> Some of the Jetronic were (gasp) analog....
> David
> 
> 
> ----- Original Message ----- 
> From: "Mike" <mlschmidt at sprintmail.com>
> To: <diy_efi at diy-efi.org>
> Sent: Friday, February 24, 2006 10:14 AM
> Subject: [Diy_efi] Motronic hacking...
> 
> 
> 
>>Anyone know of any of this sort of stuff available for the Jetronic
> 
> system?
> 
>>Mike
>>
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