Have a mostly stock '98 LX (EJ6). At my tech school my classmates in Engines class rebuilt a motor and installed it (mine was in the process of shitting the bed) ~ a month ago or so.

Had a few other piddling things to fix so the other day I removed the center dash trim area including the climate control unit to install a used item as the one I had was experiencing issues and looked like trash after someone attempted to steal my car a few years back (pry marks, bad scratches, broken plastic bits around the trim edges, etc).

After a few hours of cursing and reattaching the cable operated temp switch to the blend door I went to start the car. No dice.

The only electrical connectors I touched were the 2 for the HVAC unit as well as the radio (aftermarket head unit with properly installed wire harness adapter). Did some digging for a few minutes and realized the fuel pump wasn't priming so I checked all fuses with my DVOM-all fuses good, had battery (or otherwise specified voltage) and then I remembered about Honda's wonderful main relay issues so I got my roommate to give me a ride to advance auto where I picked up a new one.

Installed that and it didn't work.

Switched back to the old one and it fired up, ran for a few minutes.......And then died after driving 25 yards from my apt building. Had to push it back into the parking lot. At this point it was about 10pm Tuesday night.

Came back at it the next day (Wednesday) and still no fuel pump action. I checked the inputs to the old relay after reinstalling it at KOEO and found voltage at all pins except pin 4 which is the one that sends power to the pump and of course the ground pin. Checked for continuity at the plug-all wires have continuity. Checked for pin fitment and it was good. Posted for help in the facebook mechanics group I am part of and they reminded me about re-soldering the old relay so I got up today & tried that! Still nothing!

Attempted to resolder a 2nd time and still no joy. Returned the relay to the store as defective and got back home. Out of desperation I tried jumping pins 4 & 5 on the plug (bypassing the non-functional part of the relay) and the fuel pump came on. Now the car won't start still even with the pins jumpered and pump running?! Plug in my scan tool (Launch CRP129) and no I have no-comm with the PCM. Re-checked all fuses and fusible links again-all good. I'm at my whit's end and can't afford to call into work again on Saturday. Any ideas or advice? Did I fry my PCM? All lights still come on on dash (CEL, SRS, oil etc), but no engine engagement. Also jumpering SCS connector CEL stays solid in ACC position no blinking action.

Have a DVOM, all the basic hand & impact tools, access to Mitchell ProDemand via school, and the knowledge of completing 1 year of a 2 year training/certification program.

 

Check the ECU ground wires on the thermostat. Very easy to forget those when R&R engine. It's also a good idea to check all the sensor wires by wire color. The plugs are not mechanically keyed to prevent plugging into the wrong place. Honda assumes that people working on their cars should know what they are doing.

The CEL should come on and then go out when you turn the key on but don't crank. During the time it is on, the fuel pump should run then stop.

 

I thought I checked them already....as the car has been running for a bleeping MONTH since the engine swap!

 

Does the CEL cycle with key on and don't crank? If the CEL comes on and stays on, or if it does not come on at all, the ECU is not booting up and it's not going to start. This can be from lack of power or ground, or a faulty ECU.

 

Comes on & stays on.

 

My instructors in Electricity 241 & 242 (Electricity 1 & 2):

Instructor: What do we do when a component doesn't work?
Me: Verify power & ground
Ins: How?
Me: Pull wiring diagram & print it, trace it, or otherwise write it down so you know what you are looking for.
Ins: What happens if the component is SWITCHED by another component i.e. power or ground side switched from say the BCM (body control module) or PCM (Powertrain Control Module)?
Me: Verify power & ground to the controlling component FIRST before you troubleshoot the broken one.

Guess what I FORGOT to do? Verify power & ground to the PCM No ground to the PCM means....say it with me.....PCM doesn't boot up and doesn't supply power to the PGMFI relay!

TLDR: Broken ground wires at G101 lead to 3-4 days of tail chasing by yours truly.