Wednesday, November 26, 2014


The '84 Mercedes-Benz 190D hasn't been running like it should for some time now, it starts hard and doesn't idle smoothly. I figured the injectors needed attention, they probably (almost certainly) haven't been out of the engine in 205,000 miles so it was time. I ordered new Bosio injector nozzles from ID Parts. I like ordering from ID Parts since they're here in MA so the shipping is quick and cheap. I wanted Bosio nozzles because they're made in Italy which means they're NOT made in China. Word on the street is that Bosch nozzles are made in China and the QC (quality control) is all over the map.

Mark Blevins cleaned my spare injectors (thoughtfully provided by Fred), installed the nozzles and calibrated everything. He did a great job, the price was right and turnaround was fast.

The install was pretty painless, it requires a 1 1/16" deep socket, a 14mm wrench, new heat shields, a pick to get the old heat shields out, and if your injector return lines are even questionable a meter of that. My return lines are viton I'd bought from McMaster-Carr, they were still pliable and no problem at all to reuse. I guess I should buy some more, thats good stuff.

The old, nasty injectors in place.

A replacement from Mark. His packaging is perfect, he even loops the tape back on itself to make it easy to remove.

An old grotty injector on the left with a nice clean one on the right. Notice the nice new heat shield also.

I noticed that the new nozzles had a little pin that sticks out where the old ones have that missing. Once the rebuilt injectors were installed the engine fired right up. I'd put my foot into it thinking the lines would be dry and the engine would start hard. That turned out to be wrong, it fired right up and idled nice. I can tell a big difference in power off the line and when accelerating.

The nozzles I got are slightly larger than stock which in theory should give a little more fuel and thus more power. The problem of course is that this is a naturally aspirated engine so it might also lead to a little smoke. I'm pleased to say there was no noticible smoke and while I think there might be more power that could be my imagination or the power I'm feeling my just be power restored that was lost due to the old injectors being worn.

Anyway the worn injectors now go on the shelf awaiting their turn for rebuilding...

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