Diesel Injection Pump Timing

Timing tends to retard over time with wear and chain stretch

Why is injection pump timing so important? The older diesel engines will run, though poorly, when the pump gets out of time. Because of that, pump timing is often neglected when troubleshooting poor engine performance. Incorrect pump timing can result in any or all of the following:

Problem & Solution

Common among these chassis:

W115
W116
W123
W126
  • Hard starting
  • Rough running and heavy smoke during startup
  • Black smoke during acceleration
  • Poor fuel economy
  • Engine running hotter than normal

Yes that is right. If you are having problems with a hot running engine and have tried everything else to fix it,  it could be the injection pump timing. Basic instructions for checking and adjusting pump timing are covered in my manual Diesel Performance Tuning and Repair. In this manual I explain how to do it without a drip tube. Pump timing needs to be dead on for PEAK performance. Some prefer using the factory recommended drip method.  We carry the drip tubes you will need for that procedure but no instructions. Refer to the factory manual for how to perform the "drip method."