[BruceMcC]

I do pop testing with corn oil. It's safer and doesn't stink. The oil and injector temperature can vary your pressures by 50 lbs, so start with both at a known (room) temperature.

Pump the injector till it pops 2 dozen times just to clean it out and get it stabilized. Then pump with rapid hard movements and look at the spray pattern. It should be a fine narrow spray jet, not a squirt. I also use the rapid pump to determine the pop pressure. The pressure guage needle should be bouncing around the pop point. Some folks use a slow pump to determine pop pressure. Just be consistent when you're trying to match pop pressures.

Squirting is most often caused by having the tiny cross flow hole in the tip of the nozzle plugged.

Take it apart and clean it again, use a fine nylon brush bristle or a fine brass wire to poke through the cross flow hole. You must clean everything like it was a NASA project- and bits of dirt can mess things up.

Soaking the nozzle parts in corn oil and scrubbing with a toothbrush seems sufficient for cleaning. Varnish and and carbon should be cleaned off completely. I also use ethanol for cleaning, but corn oil the parts before assembly. If the pattern is still no good, it's probably time for a rebuilt nozzle.

I only bought a few spacer washers and then used a diamond hone to get the sizes I needed. You'll need a micrometer to measure the washers.

My pop tester was homemade from a grease gun, grease gun hose, some hydraulic fittings, and an injector adapter made from an old injector line end with fitting epoxy steel'd into a drilled 1/4 NPT plug.

I found it fun and very satisfying to match my injectors. My idle is now very smooth.

Bruce McCreary
(2) '85 300Ds 83 300CD
Snowflake, AZ