If you think CIS fuel injectors can just be ignored, think again. Sure, your gas engine will continue to start and run “ok”, but you may find that it is not producing the power it once did nor the fuel mileage it once delivered.
Works on all models from 1977 to 1993 with the Bosch C.I.S Fuel Injection system - see models listed below: Now you can do it yourself on the bench with this inexpensive tester- Save big $$. Ever wonder how well your old CIS fuel injectors are working?
It has been over 30 years since the last Mercedes with Bosch C.I.S. fuel injection was manufactured. If you own a 1976 to 1993 Mercedes gas engine with this type of fuel injection, you may have difficulty finding someone to work on your car. In some parts of the country, it may be impossible.
This is a critical rubber part that seals the fuel injector to the injector holder. Deterioration can result in high idle speeds and poor engine performance. Unless you have a low mileage car with soft seals, these should be changed when testing, cleaning, or replacing your fuel injectors.
This video applies to both K-jetronic and KE-jetronic fuel injection engines on Mercedes from 1976 to 1993.. Let's say you just acquired an old gas engined Mercedes and you just can not get it to run right and or even get it to start.
These are the plastic bushings that hold fuel injectors into the head of the late M116 and M117 engines. These get very brittle with age. If you are planning on removing your fuel injectors I highly recommend you order these to have on hand.
In this 20-minute instruction video, Kent will show you how to take his short kit and combine it with a tester that you can purchase online to make a leak-free, reliable, and accurate fuel pressure tester for Bosch CIS fuel injection.
Kent will take you over to his workbench and completely take apart a rusty and old fuel delivery system from a 1980 450SL and put it all back together again with some shiney new paint and parts supplied in his special kit for these cars. This video runs for 24 minutes.
We know that many of you own multiple Mercedes, including both gas and diesel models. If you own one of Kent’s fuel injector pressure testers you no doubt will want to test all your applicable mechanical fuel injectors in both types of older engines.
Most 1988 to 1993 6 cylinder CIS fuel injection delivery (FID) systems are old and tired and have not been properly maintained. These include the W201 190E 2.6, the W124 260E 300E, 300CE, 300TE, the W126 300SE, and 300SEL, and the R129 300SL.
Now available as a cost-saving kit! Six new Bosch CIS fuel injectors with six holder bushing O-ring seals. If your 6-cylinder 103 engine has over 120,000 miles and you think your injectors are ok, then you might want to think again.
After completing the pressure test on your CIS engine, you discover a problem. But how can you find out how to isolate and fix it? This is going to require some research on your part. Start by learning how the system works and how each component plays a part.
There are a few factory recommend procedures and tests you should do before you do an actual pressure test on a CIS fuel-injected engine. In this 20-minute training video, Kent will walk you through these procedures step-by-step.
To do proper system testing on CIS fuel injection, you must find a way to get the fuel pump or fuel pumps to run continuously without the engine running. This can not be done by just using the ignition key. In this 15-minute training video, Kent will show the options available to do this.
This is a common occurrence as these gas engines with Bosch C.I.S. fuel injection age. Most of them are now at least 20 + years old. The problem goes something like this. You start the engine cold and it will hardly run. It runs rough and idles very low and will even quit a few times.
In this video, you will see how the gauges are hooked up to a 560SL and how the pressures are read. The length of this 30-minute shows the detail Kent has put into filming all the critical components of doing a KE-Jetronic fuel system pressure test.
This video is specific to K- jetronic fuel-injected engines from 1976 to 1985. This includes the 350, 450, and 280 engines in the R107, W116, W123, and early W126 gas Mercedes. In this 29-minute video. Kent will show you how to hook up the gauge, run the fuel pumps, and complete the test.
This video will help you decide if you want to try to do a fuel pressure test yourself. It is a fairly simple DIY job but will all the confusion and misinformation on the internet; one would believe it is a complicated process that is hard to understand.
In this short video, Kent will give you an overview on setting up and using Version 3 of his bench mount CIS gasoline injector pressure tester.
Kent shares with you 3 key steps that you should consider doing to get your old fuel injected 6 and 8 cylinder engines running properly. These include:
New Bosch fuel filter as shown. Before ordering please make certain that this fits your Benz. Not all gas fuel filters are created equal.
With these old gas fuel injectors, sometimes you just have to "back flush" the insides to restore them to peak performance. There is no guarantee that back flush cleaning will restore every old gasoline mechanical fuel injector. Some are just plain worn out.
This 24 minute on demand training video comes with our injector back flush cleaning kit. You can purchase this video separately, but please keep in mind you will not have any of the tools or supplies to complete this procedure yourself.
In this 13-minute CIS training video, Kent will walk you through the steps recommended by Mercedes Benz to fully test the operation of the EHA valve on 1984 to 1993 4, 6, and 8-cylinder engines with KE-jetronic fuel injection.
If you acquire an older Mercedes diesel and want to test those large Bosch injectors with your V3 gasoline bench tester, you will need 4 things to complete the conversion: 3000 PSI gauge, our new capture bottle to hold the larger injectors, injector sealing kit, and Kent’s written manual and vid
We know that many of you own multiple Mercedes, including both gas and diesel models. If you own one of Kent’s fuel injector pressure testers you no doubt will want to test all your applicable mechanical fuel injectors in both types of older engines.
PLEASE NOTE: Wire color may be all red or all black (depending on stock on hand) .
More often than not you will find these cracked and broken.
In this 9 minute instructional video, Kent will explain how to test your fuel accumulator to determine whether or not it has failed internally. A failed accumulator will make your engine hard to start when hot.
PLEASE do not order in error! Check your engine first with the cover off. It should look exactly like the one you see in the picture below. LH-Jetronic fuel injection is electronic, so it does not require a fuel accumulator at the car's back end.
This tester is designed specifically for 6- and 8-cylinder engines with KE-Jetronic fuel injection. (will NOT work on the 2.3-liter four-cylinder engine). Instructions will also be provided so you can do a fuel pressure test on the LH-Jetronic fuel-injected engines of the 90s.
In this 13-minute video instruction Kent will show you how to make your own accumulator tee hose connection either using parts from. our kit ( see below) or parts you purchase yourself. This video is included free with the purchase of our kit.
As of early April, 2026, Kent has decided to revise his fuel-system pressure-test kits. New versions will be more engine-specific and include additional features to help you conduct thorough, accurate tests of your fuel injection system.
2026 Update: This hose is getting harder to obtain. We do have a kit so you can make your own. See related products below: This hose assembly was used on the fuel delivery systems in the late 1970s and early 1980s.
New in April of 2026. This is the "whole ball of wax," including 10 free on-demand training videos. Kent put this kit together for those enthusiasts who own multiple classic Mercedes from the 1970s through the 1990s. Fuel Injection back then was not as reliable as it is now.
I have used a lot of different clamping tools over the years to prevent fluids from leaking out when removing coolant, fuel, or brake fluid hoses. Most work ok. Some are hard to use in tight places. Many do not stop every last drip from coming out of the hose.
This tester is specific to K-Jetronic V8 engines due to the special fittings and adapters it includes. These included M116 and M117 engines in the W116, R107, and early W126 chassis.
IF YOU ORDER THIS IN ERROR, IT IS NOT RETURNABLE. Watch the video below to determine which WUR you have BEFORE ordering. This ONLY works on single vacuum units!!! You will find the quality of this kit is impressive, and it has things in it that other kits do not have.
PLEASE NOTE: This BASIC tester is intended for someone who knows how to hook up a pressure gauge and T hose to CIS Bosch fuel injection and has the information avialable to know the pressure specs for the engine he is testing.
This is every thing you need along with free video instructions by Kent Bergsma. Why change the K-jet fuel injectors in your M110 engine. One thing is they are very old. Second this is right now they are readily available and resonably inexpensive.
This WUR is very simple in design and has no internal diaphrams. It is also quite short compared to the other types. No instructions are included, but they are readily available on the internet by doing some google searches.
Why change K-jet injectors when "they are working?" Why change shocks when they feel ike "they are working." The deteration is very slow over time and you may not notice the difference in how the engine starts, runs, accelerates, and delivers mileage until you do this service!
This video will be an excellent example of how to save big $$$ doing the work on your own car. If your gas engine is idling too fast in neutral it could be an expensive problem, but in many cases it is due to lack of maintenance over a long period of time.
PLEASE NOTE BEFORE ORDERING: This WUR function test kit is INCLUDED in both 1976 to 1985 6-cylinder and V8 full pressure test kits (see related products below). There is no need to order this separately.
Why do a fuel system flow and pressure test? Without one, you will not know if your fuel injection is working properly. This is even more pronounced on K-Jetronic engines that incorporate a warm-up regulator. And guess where that is located on the M110 engine?
In this 26 minute instructional video Kent will show you how to hook up a CIS fuel pressure tester to your older K-jectronic gas engine.
Brand new aftermarket fuel accumulator for the 1986 to 1991 V8 engines. It is mounted near the fuel filter under the back end of the car and hardly ever gets replaced. What does it do and how do you know if it is bad.
PLEASE LOOK AT YOUR SYSTEM BEFORE ORDERING to confirm the type of accumulator you have. ( Watch the last video below for examples )For systems with ONE HOLE ACCUMULATOR only. Some 450SL, 450SLC, 450SE, 450SEL with 4.5 and W116 280SE .
Upgraded top seals for better and longer-lasting sealing properties and well as standard green seals for the bottom of the injector holder. With these seals you can clean and reuse your existing fuel injector holders / sleeves.