One time I pulled an injector and started Stinky up to let him idle before a re-torque of the injector bolt. I could hear #1 injector knock with the air in there, but I understood what was happening. Being the fidgety person I am, I did a KOER test with AE while I monitored the normal PIDs, and I saw the ICP bounce to 2200 for a few seconds. After the high ICP concluded, the knock was gone from #1 and Stinky smoothed way out. I thought "Eureka! I have a way to abbreviate getting the air out of the oil, and I have something to share with the forum." So... I shared on a couple of threads.

Wellll... I was wrong. In the interest of never wanting to lead anybody into anything that would cause undue harm to wallets or trucks, I must share what I found in the Ford PC/ED:

There is a paragraph in bold text, warning NOT to do a KOER test while air is in the oil. It specifically states to drive the truck about 20 miles before performing a KOER test. Thinking it through, this makes perfect sense - it can hammer the injector and the whole HPO system pretty hard. I feel pretty silly for not looking into this before sharing.

Yet another public service announcement from the Stink-N-Rich research and development team.

 

Ah well, I sure liked how it cleared the air after your help on the injector cup job. On a drive, we typically put the pedal down to clear the air - wouldn't that still bump ICP over 2K and accomplish the same thing? Is it really that much more gentle?

 

You are probably right Jeff, but in your scenario, you don't immediately put the truck in gear and ask for 2-3,000 psi of injection pressure where the KOER test pretty much does. Starting the truck and selecting drive or shifting into first and pulling away from the curb or driveway is probably a little more gentle than the KOER test. Just a guess on my part.

 

I'm agreeing with everybody. The truck still sees big ICP numbers while getting on the highway or climbing a hill... but it is softer, and the truck is using the fuel, not dead-heading at idle in the driveway. The bigger Fuel Injector Pulse Width softens the shock.