While not being an expert, I've owned a KDI21 and an ISE Classic Supreme (KDP22 clone) and am at least familiar with these machines.

There may be an issue with the lower wash arm.  Others here can advise on trouble spots that could impair movement.  You should definitely be closing the detergent cups.

If the rust on the racks isn't too bad, the brush-on plastisol repair is a viable fix.

About a year and a half ago I found a used Miele at the ReStore and replaced my ISE with it.  I've never looked back.  The Miele produced superior results, and just recently I tried non-phosphated pods in it since my stash of phosphated Cascade was nearly gone.  I was amazed at the sparkling results, particularly on glassware, and the generally less scummy appearance inside the tub as well.  The Miele may take twice as long as a vintage machine to get the job done but that doesn't bother me, and I don't have to concern myself with tracking down detergent with phosphates.

Just something to think about.

Ralph

Why not let it fill and take a picture of how much water is in there?  Someone here will be able to quickly tell you if that is the issue.  It sure sounds like it or you have an issue with your Wash Arm Support.  I had this issue and mine was the support.  It was blocking water to the lower arm.  Put in a replacement and it was like new again.

Oh, and I always close both covers.

If the wash arm support was bad, the arm assembly would be wobbly and revolve sloppily.

I think the cycles you posted further above simply don't include the drain sequences.  The "purge" is a short fill with brief action to clear the filter.

I've forgotten the exact sequences for my ISE, but I'm pretty sure the pre-rinse/pre wash was followed (after draining) by another fill for more action without detergent, drain, then fill for the main wash where the closed cup would be triggered to open.  However, things may have changed with the KD23 series, where Whirlpool's influence was a lot more evident than on previous KA models.

I think the clogged fill valve screen is a good guess.  I removed the flow restrictor from the fill valve on my ISE and the hole in that thing was tiny.  If the screen is obstructed, that's two strikes against having the tub fill adequately for decent wash action.

If the 23 series is anything like its immediate predecessor, water level in the tub should be at least as high as the heating element.

As I stated above, there's a restrictor inside the fill valve that can be removed.  Then you'll get a full torrent of water during the fill period and it will sound like it's hooked up to a garden hose. 

I removed the restrictor from the ISE valve because the pipes are old here and the pressure is worst in the kitchen, so the tub wasn't getting completely full by the end of the fill period.  With the restrictor removed, I turned down the water supply valve to the dishwasher so the tub would finish filling with maybe ten seconds of time to spare before the end of the timed fill.

If you're getting good results now that the tub is filling more, that bit of cavitation you're hearing may not be worth addressing.

Robert, don't abandon your drilling idea. 

The same thing has been suggested for the new dumbed-down clothes washers that have restrictors in their hot water inlets (rendering "warm" water that's barely tepid), and has provided good results.  I see no reason why you can't do the same for your dishwasher's restrictor, except it may not be as easy to drill a new relatively pliable restrictor as opposed to a hardened old one.

Ralph

I agree, but it's possible (with restrictor removed or drilled out) to find the sweet spot where the tub fills enough during the timed sequence to provide good performance, but not enough that the float is what stops the fill.

It's easy enough to figure out just by pushing down on the float and listening for the click from down below.

IIRC, on my ISE I'd sometimes hear the clicking of the float switch during wash/rinse cycles as the water was churning even though I wasn't relying on the float to stop the fill.

You're making good progress.  I feel nothing but confidence in your ability to "dial down" the water flow just enough to keep the fill timer relevant.

That's bogus.  The panels always come in a set, I'm pretty sure.  I ordered my SS panels from Sears and received both.

I have bought two sets of these and both sets came with both panels.  How was it advertised?  Did  you buy them on eBay?  I bought part B-241677 both times.

Besides eating away at the plastisol coating on the racks, another result of pre-rinsing can be etching on/clouding of glassware.

Feed your Bubble Bandit, and keep an eye out for cheap machines on craigslist that have good racks you can harvest from them.  The Re-Rack will buy you plenty of time.