1992 Accord LX
JDM H22A w/P13 ECU
Accord automatic transmission w/P19 TCU

My problem has been that the car will drive for a while, then the engine will shut off and leave me with a blown ECU fuse (under-hood 10A). Otherwise the engine swap has ran seemingly perfect in the year that it's been in.

The first time this happened the main relay and fuel pump were unplugged, then after the car sat for a bit it started up and I was able to make it home.

The second time I tried doing the same things but with no luck, so the car was towed home. More inspection involving unplugging things was done, and the car eventually started up again. This testing included the main relay (which was re-soldered for the second time in its life; I knew these were problematic so I figured 'why not?'), fuel pump, ECU, and fuel injector resistors. It got me driving again.

Then it died a third time. The car can make short trips, but going for long drives seems to do it in. Maybe something's warming up to 'optimal failure temperature' or something.

Using a DMM, everything in the ECU fuse's circuit checked out fine except for the plug going into the IACV. Main relay, injector resistors, injectors, O2 sensor... all good (I might be forgetting something at the moment but it was all looked over). Battery voltage is supposed to be dropped across that harness plug (the valve itself tested fine according to what Haynes said to test for). It was dropping 1v or something like that. Am I wrong for thinking the ECU looks to be the culprit here?

So I just replaced the ECU and a few things have changed. That IACV plug has gone from dropping just the 1 volt to now 7 volts. Trouble codes have gone from no CEL codes and four TCU codes, to a solid CEL and code 14 from the D4 light. I don't remember the old TCU codes off hand, but I'm pretty sure 14 was one of them. I haven't driven the car yet, I'm afraid this mysterious short might fry this newer ECU I paid dearly for (were OBD1 H22A1s just not available in America with automatics or what?). But I did let it run in the driveway until the engine warmed up. I've got solid engine mounts, so it's hard to tell if the engine's running rough or not - vibrations are very normal for me.

Does anyone know where this line pressure control solenoid is and how to test it? Or if anyone has other things to look for, do please speak up.

Thanks for any help!