Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
1988 Mercedes Benz 190DFACTORY OEM SERVICE PROCEDURE
Injection Nozzles
NOTE:
When testing, use clean test oil or filtered diesel fuel only. Never place hand in front of jet nozzle.
- Prior to testing, check longitudinal bore for free passage. Clean with a .007" (.18 mm) diameter wire.
- Using Bosch Injector Tester (EFEP 60 H), pump 5 times through injection nozzle on tester. Test buzzing of nozzle by slowly actuating hand lever (about one stroke per second).
- During short, fast partial strokes (at least 2 strokes per second) the pintle should be closed. Generate initial jet by moving hand lever slowly in downward direction (4-6 strokes). A vertical cord-like jet should come out of center bore.
NOTE:
On new nozzles it is difficult to generate an initial jet. Check longitudinal bore with cleaning needle of .007" (.18 mm) diameter for free passage.
Factory Service Tools
Use the Manual With the Right Hardware
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.