[Diy_efi] Jetronic

[Bill Washington]

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
>