I have a 1991 CRX DX with a D15B DPFI engine and automatic transmission.

I want to ugprade the engine to a JDM ZC DOHC Non Vtec OBD1 MDFI Engine that I can buy locally.

This will be my first engine swap and I would like to keep the automatic transmission. I believe it will bolt up to the ZC DOHC engine, please correct me if I am wrong. (This is a commuter car and I just want it to have a little more pep, and my D15B is dying and is at about 115 compression in each cylinder)

From what I have read, if I purchase a complete engine with all sensors, I should just need to buy an OBD0 to OBD1 conversion harness and wire everything up according to instructions.

I do not believe the engine I am looking at comes with an ECU, what is the best ECU for me to buy or am I mistaken and I am using the OBD0 ECU somehow?

Is there anything else I am missing that I need to make sure I have before starting besides extra wire, soldering gear, and the ECU?

Thanks in advance for the help, I have read a lot of posts, but I want to make sure I am not missing anything.

 

i see no point in going obd1 u can keep it obd0

just run a ps9 IIRC with a mpfi dizzy

 

Could you please provide a few more details, I am a total Honda newb.

What is a ps9 IIRC?

Is the MPFI dizzy already on the DOHC ZC engine I am buying or something else I have to buy? (If I need to buy it separate can you give details where to get one)

Sorry if I am asking crazy newby questions

 

Also interested in the replies. Looking to do something similar. Not the only one wanting to keep it auto. haha

 

Ok I think I figured your post out.

I would need to find an OBD0 MPFI dizzy, and a PS9 OBD ECU, and the do a wiring conversion from DPFI to MPFI?

Any other opinions on which is easiest to go to OBD1 with a new ECU or stick with OBD0 and a new dizzy and ECU?

Thanks

 

I think I want to go the OBD1 MPFI route.

I will purchase this harness, unless someone knows of one better (OBD0 DPFI > OBD1 MPFI)

http://www.hamotorsports.com/obd0-dpfi-to-obd1.html

Which OBD1 ECU should I buy for a ZC DOHC non-VTEC engine?

 

i dont get this you say your such a noob and all this ****

ask for help and we give it and still you insist on going obd1

hope you know wiring

have fun wasteing your money

 

Yes you gave your opinion, I kept reading, found conversion harnesses and it didn't sound very difficult.

If you have more reasons you would like to share on why the DPFI to MPFI conversion is easier withe a new dizzy, and P9 ECU I am willing to listen.

You can or offer a little more insight since both require extra wiring it seems.

 

i assume that the engine you are getting is a factory 92-95 OBD1 DOHC ZC and not an OBD0 ZC that has been converted to OBD1? - the factory ECU for the OBD1 DOHC ZC is a P29 - kind of hard to find - you can use a 92-95 Civic DX P06 ECU for auto trans car - you could get the P06 chipped to run the P29 fuel and ignition maps, but it will work as is

use your DPFI engine harness and follow the instructions that come with the ECU jumper harness - the Boomslang harness is a quality piece and you should have no problems wiring it - just remember that since the engine is OBD1, you won't need the injector resistor box - if, by chance, you should happen to find a JDM P29 automatic ECU, you won't need a 4-wire O2 sensor as the P29 uses a 1-wire, just like OBD0

a couple of other things you will need to do:

you will need to remove the engine mount from the driver's side end of your current engine and swap it onto the ZC - they are different between 88-91 and 92-95 - when you do this, you are going to need to slightly modify the hole in the timing belt cover where the mount comes through or find an OBD0 DOHC ZC front timing cover

the OBD1 ZC has the cooling fan switch on the thermostat housing and your D15 engine has it on the back of the block next to the oil filter - you will need to swap the 2-wire connector from the ZC engine wiring harness onto the DPFI engine harness in order to plug it in - on the DPFI harness, it is a 2-wire connector with a big round black boot - wire colors are yellow with a green stripe and solid black

the OBD1 DOHC ZC has the MAP sensor on top of the throttle body - your car uses a firewall mounted MAP sensor - you will need to extend the 3 wires for the MAP connector so that you can plug it into the MAP sensor on the throttle body - this connector is not on the engine harness - it comes out of the firewall below the MAP

 

Wow thank you for an amazingly helpful post :D

As far as I know it is a native OBD1 engine, but it is a long block only so I do not know if I will have access to an old harness or any old connectors.

I really appreciate all the info, do you have any input on what the ranting member was talking about above? Staying OBD0 with a PS9 and OBD0 MPFI Dizzy?

Pros / Cons of each? I would prefer not to do anything that will limit the engine's output since I am already sticking with a power robbing automatic

Thanks again!

 

Why are you wanting to convert to obd1 is my question. I have already done a conversion from dori to mpfi on an auto car and there is wiring involved as is. I don't see the point of going obd1 here though.

 

It is a native ODB1 engine so I just thought I would move to OBD1 with a conversion harness. Some people say it is simple some say it is not.

I have to convert from DPFI to MPFI so I know wiring is involved no matter what. Which conversion is best, staying with OBD0 MPFI or OBD1 MPFI I do not know.

If there are no cons to staying OBD0 on a ZC DOHC then I could, I just am trying to find all the details on how to perform the swap before making a decision.

 

Ok I just found out a ZC DOHC OBD0 is available.

If I went this route I will still need to convert from DFPI to MPFI, and I assume just get a PS9 ECU?

Would that be a much simpler solution?

 

it would be simpler to use the OBD0 ZC - you should really try to find a JDM PM7 ECU Automatic - it is the factory ZC ECU and will work a lot better than the PS9

 

lol that's what they have been trying to tell you. Why would you not keep it OBD0>? Less money(parts are easier to find), less work, and it will perform the same? no brainer

 

How hard is it to find that PM7 ecu? Kinda want to know also.

 

The original engine I found was OBD1 not OBD0, as stated above multiple times.

I just found an OBD0 ZC, so of course I would not be converting it to OBD1.

 

I'm researching a DPFI-MPFI swap with auto trans on my girlfreind's car and I'm honestly starting to think it would be cheaper to go OBD1. A D16A6 dizzy used online is about $65-$90 depending on the deal you find, a PS9 ECU is $75-$90 (there's ONE on ebay for $90) and wiring harnesses are at a premium for these. If I went MPFI-OBD1 I could get the D15B7 dizzy, ecu and wire harness at the junk yard for the price of a D16A6 dizzy alone.