Been troubleshooting my 96 hx 5sp for a while now. Been having a issue with the fuel pump relay not kicking on and priming the pump when I turn the key. Sometimes it takes 30 seconds to a minute and then click, the relay comes on and the pump primes and it clicks off. Like normal but just have to wait. Sometimes it comes on soon as I turn the key. It seems to be better if it's warm inside the car but if it's cold sometimes I sit for a few minutes and give up and take my other vehicle. Anyways I've cleaned all the grounds in the engine bay, verified power at the fuel pump, checked the fuse box under the hood to see if any relays or anything were bad or any corrosion, found a huge ants nest in the fuse box, did a full tear down, clean, re-grease and rebuild on it, reflowed the solder connections on the pgm-fi relay, replaced the pgm-fi with a new OEM genuine Honda one. None of this changed anything. I'm looking at my ECU now. My ECU is part# 37820-P2N-L21. According to another post on here, that suggests I have a California edition vehicle 😔. When I'm back home I will confirm this by looking at stickers under the hood if I can. Either way, can I use a 37820-P2N-A21 instead? Both of these model ECU say they are compatible with a 96 hx 5sp. I guess I'm wondering, what components does the California 96 hx 5sp have that's different. And will I get a CEL if I run the 49 state ECU? The only things I can think of that would be different is the cat and the 02 sensor and maybe an extra 02. I have replaced the exhaust from cat back and I'm like 99% sure I didn't get a California carb exhaust or anything.

Short version:
Can I run a 37820-P2N-A21 on a 96 civic hx 5sp that currently has a 37820-P2N-L21 that I believe is failing internally? Or do I need to locate an L21. thanks

*Edit
Wanted to add 1 more thing, by "will it work" I mean will it work without turning on my CEL, failing 49 state emissions, (I won't ever be registering in cali). And will it run and drive like a stock commuter car should? My hx is literally bone stock and it's staying that way and I drive around at the speed limit lol. I still need to confirm if its actually a cali car or if someone swapped the ECU from a cali hx . Will report back tho

 

Okay hopefully someone can join my conversation with myself, but I'm confused on what to do. My VECI sticker under the hood says the car meets US EPA not California anywhere on it. But it has a ECU that according to another forum member in another post on this forum, is the California version. L21. indont know if the hood was changed from a wrecking yard, or if the ECU was changed with a California one. Is there any other component or anything I can check to tell if this car is a California or EPA model so I can determine which ECU to buy?

 

Call your local Honda Parts Department and ask them to run your VIN to see what version of EPA compliance you have... then locate the appropriate ECU version.

 

Under the hood it says epa, on the ECU it's Cali, called a local Honda dealer parts dept and the guy seemed to hate his existence and humanity, and after I explained why I was called he just responded in a really depressed sounding tone "full vin". I didn't hear him fully and he just repeated it again even though I didn't say anything. I read the vin to him and all he did was say a bunch of numbers and said "that's the ECU you need" and so I go look at mine and I don't see any of those numbers on it, I tell him, and he said well that's the one you need to find. So basically I gave up on that guy. Then I pulled a Carfax on it and found that it was originally sold in Connecticut with 15 miles, and has never been registered in cali. I feel like it's most likely a epa car and someone has replaced the ECU. I ordered a genuine, oem 37820-P2N-A21 that's never been installed before. Google AI says this will be plug and play since it's the correct ECU for my car, since it does not have an immobilizer, and since it's never been in a car before etc. When I get it, I'll install it, and I hope my fuel pump finally decides to prime as soon as I turn the key. Been chasing this for a little while now. Wish me luck! Ty for the recommendation