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Factory M117 EFI?
- Thread starter gsxr
- Start date
The early M116 and M117 engines used a true EFI system, in the form of Bosch D-Jetronic. I believe this went to K-Jetronic (CIS) around the 1976 model year (give or take a year).
I am not aware of a later M117 (i.e. the aluminum-block engines introduced as of the 1981 model year) using EFI. Certainly the W126 used CIS (in the form of KE-Jetronic -- specifically the KE3 variant) from model year 1986 through the end of its production run. The earlier W126 models (1980 through 1985) used K-Jetronic CIS.
As far as I know, the 500GE also continued to use CIS during its brief production run of ~500 units in the early-mid 1990s.
As you can see from the EPC image below, for the 500GE, it also used CIS (KE-Jetronic) in all models produced. The 500GE employed the M117.965 engine, which is the standard 5-liter variant as used on the W/C126 chassis. The 5.6-liter variant as used in the 560SEL/SEC and 560SL was variant M117.968. The .968 variant was never used in the 463 (G-wagen) chassis.
I am not aware of a later M117 (i.e. the aluminum-block engines introduced as of the 1981 model year) using EFI. Certainly the W126 used CIS (in the form of KE-Jetronic -- specifically the KE3 variant) from model year 1986 through the end of its production run. The earlier W126 models (1980 through 1985) used K-Jetronic CIS.
As far as I know, the 500GE also continued to use CIS during its brief production run of ~500 units in the early-mid 1990s.
As you can see from the EPC image below, for the 500GE, it also used CIS (KE-Jetronic) in all models produced. The 500GE employed the M117.965 engine, which is the standard 5-liter variant as used on the W/C126 chassis. The 5.6-liter variant as used in the 560SEL/SEC and 560SL was variant M117.968. The .968 variant was never used in the 463 (G-wagen) chassis.
Following up on the original post, that is CLEARLY a D-Jetronic riser in the red highlighted area. This confirms my prior post.
I do know that some here believe that EFI didn't exist on MBs before introduction on the 500E in 1990, but indeed, D-Jetronic is 110% an electronic fuel injection system, and well preceded K/KE-Jetronic, and L-Jetronic (the predecessor to LH-Jetronic).
Today's lesson to edjumacate folks:
en.wikipedia.org
I do know that some here believe that EFI didn't exist on MBs before introduction on the 500E in 1990, but indeed, D-Jetronic is 110% an electronic fuel injection system, and well preceded K/KE-Jetronic, and L-Jetronic (the predecessor to LH-Jetronic).
Today's lesson to edjumacate folks:
Jetronic - Wikipedia
Any 1970-72 280SE/300SEL 3.5 or 1971-1972 280SE 4.5 or 300SEL 4.5 (all W111/112 and W108/109 chssis cars) also will have D-Jetronic on their iron-block M116 and M117 engines. It's very common in the US, especially the 4.5 cars, as a lot of them were brought into the US and a fair number of them still survive.
The ECUs do go bad with age and heat cycles, but can be refirbished. Some years back I actually brought one from the US to Germany for a friend, who owns a 3.5L M116 engine car. The D-Jet ECUs seem a bit easier to source and refirb here in the US than elsewhere.
The ECUs do go bad with age and heat cycles, but can be refirbished. Some years back I actually brought one from the US to Germany for a friend, who owns a 3.5L M116 engine car. The D-Jet ECUs seem a bit easier to source and refirb here in the US than elsewhere.
It wasn't a downgrade. MB (and all other major European carmakers) wouldn't have ditched D-Jet for CIS unless it had significant benefits.
Remember that CIS was the first generation of fuel injection that accounted for improved efficiency and emissions, including the K-Lambda and then KEx variants. These were expressly designed to improve emissions, while also improving power generation and efficiency (MPG), while affording an overall much simpler system that was easier to diagnose in the age before computer diagnosis (OBD, CAN, etc.) came on the scene.
This is why the 119.96x was just as powerful, and pretty much just as efficient, as the 119.97x engines.
They had to move to LH-Jet because of OBD and the CAN system. Cars before that only used a few individual computers that were not interconnected (i.e. the late W126 basically just used a KE-Jet and an ABS computer). Even the HFM cars didn't use a CANbus.
I totally forgot about the D-Jet M117 and I have 3 of those engines in my shop 
There was a guy I knew years ago who put a 5.0 motor from a 450SLC 5.0 into a W111 coupe, mated to a 5 speed manual. He used a D-jet intake to convert the engine ot megasquirt EFI. I think he also used the mechanical lifters. He sent me some dyno videos. IIRC , he was making about 280HP at the wheels.
D-jetronic can be problematic these days as parts getting harder to find If it runs well, great but if it doesnt, it's a real pain to fix. My favorite version of D-jetronic is the one in my Jaguar XJ12C. It's a version that was licensed by Lucas used installed in a V12 which makes it the most reliable version of D-Jetronic.
There was a guy I knew years ago who put a 5.0 motor from a 450SLC 5.0 into a W111 coupe, mated to a 5 speed manual. He used a D-jet intake to convert the engine ot megasquirt EFI. I think he also used the mechanical lifters. He sent me some dyno videos. IIRC , he was making about 280HP at the wheels.
D-jetronic can be problematic these days as parts getting harder to find If it runs well, great but if it doesnt, it's a real pain to fix. My favorite version of D-jetronic is the one in my Jaguar XJ12C. It's a version that was licensed by Lucas used installed in a V12 which makes it the most reliable version of D-Jetronic.
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I think when Bosch debuted the D-jet in the late 60’s on VW Squarback cars D-jet was the answer at the time for tightening emissions. Just about every European auto manufacturer used it n one form or another. It wasn’t without issues though VW had a lot of issues with drivability due to using generators and having grounding issues. Injectors and fuel hoses leaked causing engine fires. The system was pure analog and had no limp home capability so a failed head temp or coolant temp sensor would leave you stranded.
I remember the Porsche 914 used to have the control unit, fuel pump, and critical grounds under the battery tray! Nothing wrong with that decision? Mercedes used the D-jet on the R107 cars and when thermal reactors were used in 74-75 there were all kinds of issues. 76 CiS cars were no better. CIS was the better solution again for tightening emissions and while not perfect was a really robust system. Personally I love CIS cars. Also remember the D-jetronic was developed from design patents bought from the Bendix corporation in the late 50’s.
I remember the Porsche 914 used to have the control unit, fuel pump, and critical grounds under the battery tray! Nothing wrong with that decision? Mercedes used the D-jet on the R107 cars and when thermal reactors were used in 74-75 there were all kinds of issues. 76 CiS cars were no better. CIS was the better solution again for tightening emissions and while not perfect was a really robust system. Personally I love CIS cars. Also remember the D-jetronic was developed from design patents bought from the Bendix corporation in the late 50’s.
That is one important point about CIS (all variants) that make it a true winner.
CIS will ALWAYS get you home with a limp-home mode if something does fail. For KE-Jet systems, even the ECU has a limp-home mode in addition to the mechanical portions of the system.
You can't always say that about other non-CIS x-Jetronic injection systems. And yes, agreed, some of the componentry of the D-Jet system (not just the ECU) could be troublesome, unreliable, difficult to diagnose, and DIFFICULT TO FIND REPLACEMENT PARTS FOR.
K-Jet is easy to diagnose with relatively simple tools, and if you know what you are doing it's actually a very simple system. Parts continue to be readily available (i.e. injectors), and other parts like the fuel distributor are completely rebuildable either as a good DIY or by an expert. The parts themselves do tend to be reliable (fuel distributor, intake air plate) and don't require a lot of maintenance. K-Jetronic also self-adapts as parts wear.
Injectors' internal springs do eventually weaken and injectors will dribble, but they are readily available and easy to replace. And they are still relatively inexpensive -- perhaps $40-50 apiece. Compare that to a new M119 injector.
CIS will ALWAYS get you home with a limp-home mode if something does fail. For KE-Jet systems, even the ECU has a limp-home mode in addition to the mechanical portions of the system.
You can't always say that about other non-CIS x-Jetronic injection systems. And yes, agreed, some of the componentry of the D-Jet system (not just the ECU) could be troublesome, unreliable, difficult to diagnose, and DIFFICULT TO FIND REPLACEMENT PARTS FOR.
K-Jet is easy to diagnose with relatively simple tools, and if you know what you are doing it's actually a very simple system. Parts continue to be readily available (i.e. injectors), and other parts like the fuel distributor are completely rebuildable either as a good DIY or by an expert. The parts themselves do tend to be reliable (fuel distributor, intake air plate) and don't require a lot of maintenance. K-Jetronic also self-adapts as parts wear.
Injectors' internal springs do eventually weaken and injectors will dribble, but they are readily available and easy to replace. And they are still relatively inexpensive -- perhaps $40-50 apiece. Compare that to a new M119 injector.
Respectfully, NOTHING was ever "downgraded" by switching it to K or KE. It was vastly superior to anything that it replaced on any engine ever made by anybody. And I don't know how much of it is attributable to the injection systems, because there are a number of other things to consider, but a well sorted KE M119 makes a LH M119 feel lifeless by comparison. Lots of new car customers complained about the anodyne response of their '93 through '95 SL500 compare to the '90 through '92 that they were turning in.
