Bosch Fuel Injection Terminology


MikeC

New member
At the risk of sounding like a complete fool.. here goes. In my struggle to learn as much as I can, I am looking for detailed information about the fuel injection on my 83 water cooled westy. Digijet is the name given by VW and Digifant was used in the later vanagons.
All the references I can find from Bosch, however, refer to jetronic (K, KE, L, LH) and monotronic. I find no Bosch reference to Digijet and Digifant. Can anyone help me out with the terminology??
thanks! :confused:
 

Capt. Mike

Moderator
From VW's P/N WSP 521 133 00 Service Training manual (June '86):

New on the 2.1 liter Vanagon engine is the Digifant fuel and ignition control system. Digifant is a development of the Digi-Jet fuel injection system combined with the map controled digital ignition system.

Through the use of a single control unit, all of the functions of the fuel system, ignition system and oxygen sensor system are carefully controlled to provide optimum mixture and ignition control . . .

A new idle stabilization system has been incorporated to further streamline the system and eliminates the need for a digital idle stabilizer and auxiliary air regulator.

First, you have a Digijet which is an analog system. The Digifant is digital. You will have to go to Bosch to find out which of their systems is closest to the VW Digijet, but as the systems are custom modified from a basic Bosch system, and may incorporate features from several, I'd hesitate to jump straight into a Bosch generic manual as some cure-all. I think you'll also find the Bosch manual pretty much repeats the VW (or vice-versa). Although Digijet may be a variation of one of the basic Bosch systems, do not expect parts, particularly control modules and sensors, to be interchangeable.

However, Bosch has published manuals for specific OEM systems in the past and is a nice supplement to the VW manual. I have one for the mechanical system in the Porsche and it adds a few clearer pictures and specs. Again, contact Bosch.
 

treejay

New member
I've been trying to learn about my fuel injection system, and with research on the web, this is what I found in a document entitled "VW Fuel Injection System Types" by Jim Thompson at http://www.type2.com/library/fuel/vfityp.htm.
"L-Jetronic: The L is short for Luft, the German word for air. Air flow into the engine is measured by an air-flow sensor with a movable vane to indicate the engine load.....L-Jetronic was often called Air-Flow Controlled (AFC) injection to further separate it from the pressure-controlled D-Jetronic.

(My note: "Digijet" is the same as L-Jetronic with a few VW add-ons. It's a licensed system from Bosch)."

"Motronic: The first "engine-management" system. It combines L-Jetronic pulsed fuel injection with electronic ignition timing control in one control unit. In most engines, it also has electronic idle stabilization for a complete engine-management system.

Volkswagen Digifant: This pulsed system was partly designed by Volkswagen, but operates pretty much as Bosch Motronic does. It's timing control is less complicated than the Bosch Motronic map. It does not have a knock sensor.

(My note: VW Digifant II does have a knock sensor.)"
 

maniakos321

New member
hello to everyone.. my name is George and i study as engineer mechanic. i want to find out how works the monotronic fuel injection system. i also have to write a paper about this. if can anyone help me please send me email : papadimitriou4551@yahoo.gr
thanks
 

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