2003 Civic VTEC engine cuts out above 3400 RPMs

Honda dealer says their $12,000 computer can't even sense or read the ecm to obtain codes.

I purchased one of those Honda civic engines from Japan from a distributer in the states, and had a mechanic install it. After his installation, the check engine light stayed on and engine cut out over 3800 rpms. The mechanic said he couldn’t do it but Honda Dealership had to re flash the ECM. Honda's diagnosis disagreed and found that my mechanic needed to swap Japanese engine's wire harness w/ removed engine’s harness. According to the engine distributer and Honda”Japan engine wire harnesses are not compatible with US civic engines." Honda also found a bad Vtec solenoid and a missing pressure sensor (which is normally located beneath Vtec solenoid in US engines). This engine also was missing a pressure sensor (not required for engines in Japan) and their harness didn’t have wires for pressure sensor required for US civic engines. After these corrections were made, engine ran fine for about 2 months. Until the latest symptoms appeared (check engine, seat belt and key lights stayed on. After Honda diagnosed this second complaint, the TAC stopped working. Can’t imagine why or what they did or maybe it’s just coincidental? My mechanic uses Mitchell’s online software and procedures and couldn’t find the problem. Honda’s dealer techs said they also checked for ground and voltage problems. Yet, neither shop has been able to find the problem. But, you think if I try your recommended tests that I should be able to find the problem?
Thanks. At my wits end.

I performed the measurement steps above. Steps 1-5 were ok, and says to then jump to step 10. The last step says "o volts" should be indicated by measuring between 5 & 7. I got 1.7 volts. Does that mean anything?
I was able to borrow a scanner, but it still was not able to read anything in the ecm. It says to check connections. I don't understand why it can't read (see) the ecm, when all the other tests check ok, accept for the 1.7v. How are we to know if the ecm needs updating? I guess the shop has to update if required? If I get wrecking yard ecm, won't I still have to have the dealership do something to it, like program the keys and anything else? Will the car still run in safe mode after initial install of newer ecm, before dealer reprograms?

I did get a good check for continuity between pin 7 and e23(while unplugged from ecm) Should I check and see if there is a short between pin 7 & any other pin in e23 plug if there are no shorts between pin 7 and plug e23, where else should I be checking? I was able to subscribe to alldata as well. So with this and your help and the borrowed scanner hopefully i'll make headway to a solution. Thanks

Been reading blogs online, lot of info suggesting jumped timing belt. Can't understand why, if this is the problem, why scanner can't read the ecm. What is the best way to check if timing belt has slipped a tooth. Are these civics what they call an interference design, which means a timing belt issue could destroy the valves?