The Test Benches
Testing your Fuel Injection Pump
It's not just the expertise that's hard to find when it comes to restoring a fuel injection pump. A working test bench 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 fuel injection pumps are, not only did Bosch engineer the pumps themselves, but they also engineered a series of test benches to perfect the mechanical settings for their pumps as they developed 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 a gasoline fuel injection pump.
EFEP 5C
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EFEP 25A
EFEP 385A
EFEP 270
The general setup of the test bench has remained relatively similar from the EFEP 5C of the 40s and 50s to the EFEP 270 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 fuel injection pump experts 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 270 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.
The 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 385 (not pictured) is currently being restored and will be dedicated to W198 300SL fuel injection pumps.
Our Benches
Our shop features three Bosch benches and one modified Bacharach bench used for display, education and demonstrations.
Our Bosch benches are restored and modified examples of the EFEP 385A and 270 seen above and to the left while the Bacharach bench is a heavily modified diesel bench with a few features that make it ideal for testing questionable pumps and diagnosing major issues before shifting them over for fine-tuning.
