I recently had my injector pump rebuilt ('94 E350), and my glow plug controller replaced. I no longer have cold starting problems, but I have noticed that it is a lot louder than I am used to. Before the rebuild, I had a real problem starting in the cold, but once it warmed up and got running, it would purr pretty inoffensively. Now, I don't have any starting problems, but it sounds much louder - almost like the oil was excessively low (it's not - I checked), with the characteristic diesel "clack" noise being much more pronounced than it was prior to servicing. Is this to be expected now that the injector pump is producing the correct pressure, or is it possible that the mechanic made a mistake or damaged something else?

 

The timing is probably more advanced than it was.
When the pump pressure is lower it takes longer to build enough pressure to open the injector. This delays the timing even though it is set in the right place. retarded timing will make it run quieter, have less power, and get less MPG's.

Does the truck run a lot better?
You may ask if the mechanic if he just reinstalled the pump to the index mark as it was set or if he actually timed the engine.

If he just reinstalled it to the index mark, you may want to have the timing set.
About 7.5 degrees BTDC is where it should run it's best.

 

try some diesel kleen or other fuel cleaner and see if the added lub makes it any better like they claim

 

Yep, what Dave said

 

Get the timing checked/set correctly for sure, too far advanced will burn the tips off the GPs and you will have starting problems again.

 

What he said!!