Did the 88-91 use all the same ecu's?

 

All models and years

 

it depends, the correct answer is no i believe theres at least 3 different kinds. the PM-5 (dpfi). PM-6 (mpfi) this one comes in si, 90-91 ex 4 doors and 4wd wagon models, and then theres the PM-7, its strictly for the DOHC ZC engine. i would say theres 4, but i dont know if honda paired the PR-3 with the Si-R models.

 

It helps to search...

PG7 : 86-89 Integra (86-87 vac advance, 88-89 electronic advance)
PM5 : 88-91 Civic/CRX DX
PM6 : 88-91 Civic/CRX SOHC Si
PM7 : 89-91 DOHC ZC (JDM 'EF' ECU)
PM8 : 88-91 CRX HF
PR2 : 89-91 ZC (Euro)
PR3 : 89-91 JDM B16A EF8/9
PR3 -J00 or J51 : 92 JDM Integra B16A EF8/9
PW0 : 89-91 JDM B16A EF8/9 DA6-XSi
PR4 : 90-91 Integra LS/GS
PS9 : 88-91 4 door Civic EX Auto

 

see i need a new underdash wiring harness, thats the reason why i ask. ive got a 88 si, and what you said n3va 88-91 sohc si have the same ecu's. so thank you for the info

 

You should have said that... because no not even all the wiring harnesses are the same... '88-89 are typically the same and '90-91 are the same. I could be wrong, but I think the '88 CRX Si model is the only oddball year/model that you can't use any other harness and plug and play...

 

yeah i figure there was a little bit of difference, but the only thing im worried about is the ecu part of the wire. i can add all the little things that are different. convert it to 89-91 wiring crx with a 88 chassis basically. ACTUALLY i dont even think the ecu part of the wiring would matter anyways when i swap the motor.

 

The ECU plugs would be of your least concerns... all OBD-0 ECU's have the same plugs be it Honda or Acura... same with OBD-1, OBD-2a, OBD-2b... You can always add pins or move a couple around to get it to be how you need it.

 

Thanks for the help

 

what are you planning on swapping it out for? same motor or something else? some motors will require some wiring modification, said yours is si so it's already wired for mpfi, which will save some trouble, but you need to search for motor and application specific wiring changes if any

 

im dropping a b18a1 into it, and im pretty sure the wiring is from other Si's just different year. idk, im still trying to get in contact with this dude in the For Sale threads. Once the motor is in, then ill start researching the wiring. but thanks for the advice

 

You have an Si so it's already MPFI so all you have to do to run your b18 is plug a PR4 ecu in (no swaping wires nessasary)

 

so its plug & play with the si wiring?

 

Yes, the ecu plugs right in and that's all you need (wiring wise) you have 4 injectors already. Your just going from a 1.6L to a 1.8L.

 

Alright so the guy might have a si underdash fusebox. And he said that the wiring harness is no good. But he has a dx wiring harness. Will that be the same? Could I use that harness?

 

Irrelevant to your application, but useful on a search for ECU differences.

There are differences between the ECUs themselves.

http://ef-honda.com/ben/PM6diff.php

 

Ok so it has an Si fusebox but the underdash harness is from a Dx? What about the engine and rest of the cabin harness is that also Dx? If you have a Dx engine harness you can still use it but you will have to modify it to run MPFI (aka DPFI 2 MPFI).

 

So I'll just get a si harness, to save some time.

 

He's parting out 2 crx's. Ones an si the other is a dx

 

I'm just trying to restore my car with the right parts. I wanna learn more about the wiring and ecu's and what not. So I'm just asking questions.

 

And since I'm here to learn, why do people convert OBD-0 to OBD-1 etc? What does that benefit?

 

Everything... it has way more support for tuning, even if you just run stock you have a 4 wire O2 sensor... I could go on and on - but just accept the fact that it is WAY better and people even convert from OBD-2 to OBD-1 to reap the benefit.

 

I might do that