Scott Little

If you look at my other thread I just swapped in a B20b into a 99 Civic. I intended to run OBD1 and use the p75 ECU that I already have but for some reason it does not want to fire with the P75 ECU and Conversion harness. Car fires up without any issue with the stock OBD2 ECU from the Civic. I had considered going Obd2 anyway since the car is obd2, the engine is obd2 and the harness is obd2. I like the additional trouble codes and being able to use the obd2 scan tool. This is going to be a daily driver so I have no intention of tuning or chipping the ecu.


I was hoping to find something plug and play, I was hoping to not need a jumper harness. The plugs look identical so I'm not sure what the difference is.


I thought it would be easy to pick and OBD2 P75 but there are a few options and I want to make sure I get the right one.


37820-P75-a02 Manual ECU from 96-99 Integra LS
37820-P75-C05 Manual ECU from 00-01 Integra
37820-P75-335 Manual ECU from 96-99 Integra LS(Notes says "will not plug into 99 and 00 civics without a jumper harness!")

rollinmyda

iTrader: (19)

The P75 really doesn't run a b20 optimally. Close enough? Maybe. But it will run lean on cold starts and WOT. If you don't intend to step down to OBD1 I would suggest getting an aftermarket FPR and gauge and bumping fuel pressure slightly.

Scott Little

It ran great on the OBD1 P75. But then again it was never tuned or anything so you could be right. I have read a lot of posts that say that the p75 is the best choice for the b20.


It looks like I ordered the wrong Jumper harness for the OBD1 ECU. The 99 civic is obd2b and I ordered the obd2a jumper. I may still change over to obd2 anyway.


The 37820-P75-C05 is an OBD2b Manual ECU. I think this one may be the right fit without Jumper harness.


The Ao2 and 335 appear to be obd2a ECU's


Anyone have any input on this?

blackeg

it seems like it ran great until you put a wideband on it and see 14.0:1 at wide open throttle lol. an adjustable fpr and somewhere between 5-10 more psi will do the trick on the p75 ecu.

staying obd2 your option is to get an obd2b-2a stepdown harness which are an assload of money compared to the other harnesses and then use a 96-98 integra ecu.
all that said its probably the easiest and most hassle free way to go.

Scott Little

What about using 37820-P75-C05 which appears to be an OBD2b Manual P75 from the 00-01 Integra? That in theory should bolt right up without jumper harness.


I am a little hesitant to add in the adjustable FPR. Without wideband and at least a street tune I may be doing more harm than good. I know more fuel is safer but without any way to gauge it I wont know where I am.

HondaPartsHero

The 00-01 Integra ECUs have immobilizers so that's not a good option. Why not use a CRV PHK ECU?

https://www.ebay.com/ulk/itm/262334400453

Scott Little

Well crap, ok that explains that. Is the CRV ECU a good option? I'm using the LS intake manifold and injectors and such so I thought the P75 was a much better option. I do see some Manual ones out on Ebay. They are all AWD ecus, I don't know if that would make a difference. What year ECU would I need if that was a good option?


Just a note, I got the correct Jumper harness for the OBD1 p75 and she fired right up. No codes or anything which was nice. Have not driven it yet because I have been busy with other things but she sounds good.

tony_2018

I ran an obd2a p75 on a high compression b20, no issues. I will also say I had done all the maintenance work on the block before dropping it in.

Jah21

Hey what psi are you running for that?