Fuel Injection Swaps
by Richard Atwell
There is a Fuel Injection (Bosch Parts Interchange) cross reference at the Type.2com website that is a great resource. I've summarized the information into table format below to make it easier to understand at a glance how Fi components are shared between the models.
Bosch L-Jetronic is a simple system compared to the earlier designs like Bosch D-Jetronic on the Type 3 VWs and the D-Jet 914s. Compared to those systems, the parts are more readily available, they are simpler to diagnose and the connectors are more robust. Although a vehicle hasn't left the factory with L-Jet the technology in over 2 decades, it lives on in the Bosch Motronic engine management systems available in newer cars.
VW Baywindow L-Jet configurations can be broken down into 4 groups:
79 CA models are unique because they have an O2 sensor and special ECU with a built-in rev limiter. All of the other models rely on a rev limiting rotor in the distributor to limit the RPMs to 5400.
76 1/2 - 78 models and 79 Fed models are the most common. The sales numbers were the highest and you are more likely to find these models at the junkyard than any other models. The all have a 7-pin AFM and a mechanical EGR valve. The late 76 models have their own harness and a microswitch on the throttle but are otherwise the same. The 7th pin is for an air temperature sensor inside the AFM.
75 - 76 1/2 models models have a 6-pin AFM and an electro-vacuum EGR valve. Because they lack the air temp sensor, these models have an intake air preheat pipe that is part of the cross over pipe that's seen on the original exhaust setup.
74 CA Automatic models are very rare. They have a 1 year only harness and no decel valve.
When you go to the junkyard, take this table along to help you pick out compatible parts without having to memorize the Bosch part numbers.
When I write Shared 020 I mean that the Bosch part ending in 020 is shared between those model years in the table.
|Part||Abbr.||79 CA||79 Fed||78||77||late 76||early 76||75||74|
|Air Flow meter||AFM||022||Shared 020||Shared 018||Shared 012|
|Auxiliary Air Regulator NLA||AAR||Universal 022 906 045A|
|Cold Start Valve||CSV||Universal 022 906 171B (Type 2 only)|
|Decel Value NLA||Unique||Unique||Shared *1||Shared *2||n/a|
|Double Relay||DR||13-pin version||Shared 11-pin 071 906 059 (was 022 906 059)|
|Electronic Control Unit||ECU||4 combinations/year (manual/auto x federal/CA)|
|Fuel Filter||Universal 133 133 511|
|Fuel Injectors||Universal 022 906 031|
|Injector seals small||Universal 311 133 261A|
|Injector seals large||Universal 311 133 263|
|Fuel Injection Harness NLA||1 yr only||Shared||1/2 yr only||Shared||1 yr only|
|Fuel Pump||Universal 043 906 091|
|Pressure Regulator||PR||Universal 022 906 035|
|Series Resistors||SR||n/a||Universal 022 906 079|
|Temp Sensor II||TS2||Universal 311 906 041A|
|Thermo Time Switch||TTS||Universal 043 906 163A (Type 2 only)*3||043 906 163||063 906 163||022 906 163||311-906-163C|
|Oxygen sensor||O2S||1 yr only||n/a|
Universal also means you can use this part from a FI beetle unless the part number is followed by (Type 2 only).
*1 - See this Type2.com article for part numbers for high altitude and automatic only versions of the Decel Valve.
*2 - Automatics used electrically controlled decel valve otherwise used same Decel Valve as later manuals.
*3 - The 043 906 143A TTS supersedes all other versions so it's compatible throughout.
See my TS2 article for all the part numbers I'm come across for this seemingly identical part.
Vanagon AFMs and Decel values are different than baywindow versions but the rest of the components are the same as the 79 Federal models with the exception of the Oxygen sensor which is shared with the 79 CA model. The ECUs (all 4 of them) are the same as the 79 models.
|Part||Abbr.||83 CA||82 CA||81 CA||80 CA||83 Fed||82 Fed||81 Fed||80 Fed|
|Air Flow meter||AFM||Shared 030||Unique 025||Unique 038||Shared 032|
|Electronic Control Unit||ECU||4 combinations total (manual/auto x federal/CA)|
|Decel Valve||Shared 319||Shared 317|
|Double Relay||DR||Shared 13-pin version||Shared 11-pin version|
What about waterboxers? Yep there are a few compatible and no doubt low mileage parts:
|Fuel Pump||0 580 463 016||84-91|
|Aux Air Regulator||AAR||0 280 140 101||84-85|
Keep in mind that although Vanagons went watercooled mid way though 83 those models weren't available in the US until 84.
The intake boot and harness obviously won't fit a bus but many of the universal components listed in the first table will. Here are some of the beetle part number so you can distinguish them from the bus part because they look similar. The CSV is easy to spot because it only has an inlet and no outlet.
|Air Flow meter||AFM||043 906 301|
|Electronic Control Unit||ECU||043 906 021|
|Cold Start Valve||CSV||043 906 171|
|Decel Valve||311 133 551|
|Thermo Time Switch||TTS||043 906 163|
Certainly there exists a lot of confusion with regard to parts especially in the case of the ECU since so many versions exists. Since Bosch does not publish technical details about these components bus owners have had to make guesses and experiment with component swaps.
|Model Year||California Manual||California Automatic||Federal Manual||Federal Automatic|
I don't recommend getting a replacement ECU from the VW dealer. Aside from paying too much you'll probably get a unit remanufactured by Robert Bosch Corp. for VWoA instead of the new unit you paid the price for. Look for an X after the VW number and/or REV after the Bosch number if there is no other indication on the box.
08/12/04 - Created
09/28/04 - Added unique 79 CA AFM
10/31/04 - Added FI beetle parts and correct aircooled Vanagon info
09/07/11 - Fixed broken photos, added translate button, updated footer
09/19/11 - Fixed 77 and 76 AFM slots in table (thanks Joe)