The Test Benches
Testing BOSCH Fuel Injection PumpS
It's not just the expertise that's hard to find when it comes to restoring Bosch fuel injection pumps. A working Bosch test bench for Mechanical Fuel Injection (MFI) pumps can be hard to come by and, being 60+ years old, comes with a unique set of challenges all its own, often needing a bit of restoration themselves.
As a sign of just how complicated Bosch fuel injection pumps are, not only did Bosch engineer the pumps themselves, but they also engineered a series of test benches to perfect Mechanical Fuel Injection (MFI) settings for their pumps as they evolved through the years.
To complicate matters further, all test benches were originally designed for diesel engines, so even more modifications have to be made for these benches to calibrate gasoline Bosch fuel injection pumps.
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The general setup of the Bosch Mechanical Fuel Injection (MFI) test bench has remained relatively similar from the EFEP 5C of the 40s and 50s to the EPS 270s and 515s used in the later years of mechanical fuel injection (MFI) before electronic fuel injection (EFI) was introduced.
Not only are we one of the few shops working with Bosch fuel injection pumps in the country, but we employ a number of benches carefully restored by our own fuel injection pump experts to ensure your restored pump is working at its highest level.
The EFEP 385 is our dedicated 2-plunger bench used for the following vehicles and respective production years:
- 220SE Ponton, Coupe, & Cabriolet W128 1958-1960
- 220SEb Fintail, Coupe, & Cabriolet W111 1959-1965
- 300SE Fintail, Coupe, & Cabriolet W112 1961-1963
Our second EFEP 385, produced in December of 1977, (not pictured) is currently being restored and will be dedicated to W198 300SL fuel injection pumps.
The EPS 270, made in January 1982, is our main test bench currently set up for 6-plunger models. This would be used to test and calibrate fuel injection pumps for a variety of vehicles including all W113 models. It can accommodate up to 8 plungers which would be used for W100s and W109s, aka the famed 600 and 300SEL 6.3.
This EFEP 515, made in September 1979, is one of our main benches and is currently set up for 6-plunger models, though the bench itself can accommodate up to 12. The 515 was the successor of the 270 and has a few features that make it a bit more ideal for diesel pumps, though it still works well for any fuel injection pump commonly found on W113s.
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Our shop features four Bosch Mechanical Fuel Injection pump benches.
Our Bosch benches are restored and modified examples of the EFEP 385A and EPS 270 seen above and to the left. We also use a Bosch EFEP 515 and are in progress on the restoration of a EFEP 390 that will be used for display or educational purposes.
See what testing a fuel injection pump looks like here.