As of June 14, 2026, I will include an additional attachment in my D-Jetronic Fuel Injection Pressure Test kit. This will allow you to avoid pulling the hose of the cold start injector if you so choose.
Original fuel filters for these models do NOT come with the right-angle fitting that attaches to the filter inlet (see pictures below). On some occasions, this fitting is missing or rusted beyond use. In that case, you will need a new fitting, but the original fittings are no longer available.
The wiring plug covers must be removed with a special tool in order to install these boots. The old covers will break when you try to remove them. We recommend you buy new wiring covers when replacing either my aftermarket custom-made silicone boots or the original rubber boots.
In Kent's 32-minute video on rewiring the plugs on your D-jetronic fuel injectors, he will walk you through the two options on how you can use this kit - then show you how in do it and finally give you some tips on automotive wire splicing using the best tools and supplies.
On most D-jetronic engines, the fuel injector wiring plugs are hard and brittle, and the boots are torn or missing altogether. You may say, "If it is working, why fix it? Watch the videos below to understand why this is important and how easy it would be for you to do it yourself.
The original fuel filter has a rigid right-angle fitting, as shown in the pictures below. We do not provide this fitting in our fuel delivery kits as more often than not it can be removed from your old filter and installed in the new filter we provide.
Testing fuel pressure is a simple procedure on the D-Jetronic engines, but it is ABSOLUTELY essential. If your fuel pressure is off even a few pounds, it will dramatically change the fuel mixture, and your engine will end up running too rich or too lean.
In this 23-minute step-by-step "how-to" video, Kent will show you how to install a new set of fuel injectors in your early D-Jetronic engine. This video is included free with the purchase of our early 3.5 and 4.5 fuel injector sets.
The subjects included are:
If you plan to replace, test, or service your electronic fuel injectors you first must determine which bottom seals you will need. If you have a 1970 or 1973 model, you most likely have the single-bottom seal (unless your engine has been changed).
DO NOT ORDER UNTIL YOU REMOVE ONE INJECTOR IN YOUR ENGINE AND INSPECT THE HOLE. Sometime in 1974, Mercedes changed the way these injectors were sealed into the head to prevent air leaks. A "YELLOWISH" nylon sleeve was added along with two seals on the lower end of the fuel injector.
These plugs will NOT work on your original injectors. They will ONLY work on our new replacements (see below). These plugs are a good alternative to the damaged originals on your D-Jetronic fuel-injected engine only if you are installing our new injectors.
These are the critical seals that go on the D-jetronic fuel injectors. If they leak air, your engine with idle high, start poorly and run lean, which can damage the pistons. We recommend you replace these whenever you remove and replace the injectors.
These will fit W108, W109, and W111 with the very early 3.5 V8 engines only. WARNING: MAKE CERTAIN your current injectors are yellow at the top. A restocking fee will apply if you pl