2008 Odyssey Oil Pressure Issues

[schneidm]

I just rebuilt my J35A7 engine. New heads, rockers, piston rings, oil pump, timing belt, etc. It started immediately. I have run it about a total of 30-45 minutes at this point.  Immediately, I had a high idle at 2000 RPM, a P3400 code, engine is stuck in limp mode and cannot accelerate past about 3300 RPM, and some random misfires that seem to change with each run of the engine.  I am concerned with engine oil pressure first.

I never had an oil pressure idiot light on the dash, but I get this P3400 code which suggests there is no oil pressure at the rocker arm bank closest to the firewall.

Is there an oil pressure sending unit that serves only the dash idiot light? Why would that light stay off while the oil pressure switches on the rocker arm are detecting no or insufficient oil pressure? (yes the dash light works... I have the oil pressure light illuminated with the key on but engine not running)

I unplugged both oil pressure switches to see if I would get a second code and I did not. Instead, I got a flashing check engine light AND the P3400 code did not happen.  Not sure why. I get the P3400 everytime I run it normally.

Also, I am having a very hard time finding a manual oil pressure gauge setup that will fit the Honda.  My tester is SAE/NPT and the oil pressure switch on the Honda J35A7 is 10mm x 1.25. No one has an adaptor for this (male 10mm x 1.25, female 1/8 x 27 NPT). I am not sure why it so hard for me to locate a manual oil pressure gauge that is compatible with my Honda engine.

Bottomline is that I am scared to run the engine any longer without a manual oil pressure test so I can be certain if my oil pressure switch is bad or if there is indeed no oil pressure.  

[schneidm]

If anyone becomes interested in this, here is an active thread on the problem.

https://www.odyclub.com/threads/2008-odyssey-p3400-code-and-oil-pressure-issues.372522/