dohc zc swap

[sinezter]

ok i searched and what i found wasnt that great, so im lookin for help this way.. so i have a 89 civic dx hatch, with a d15b2 engine in it.. im doing an engine swap and i have a 88-91 jdm dohc zc engine.. and i have heard that these drop in and bolt right up, but i have heard there will be problems with the wireing? is that true? is there any other problems im going to run into? what egzactly is everything im going to have to do? also do i need an intermediat shaft? i have no idea what that is, but is it nessisary and where could i get it if it is? thx

 

[jlicrx]

the DOHC ZC will drop right in and bolt right up to everything in your DX - you will need to do the DPFI to MPFI wiring changes using the DX engine harness that was on your D15B2 and you will need a PM7, PG7 or PM6 ECU - go here for instructions for the wiring:

http://www.zcspeed.com/DXZCwiring.pdf

unless you get a ZC transmission, you don't need an intermediate shaft - just use your DX (or find one from an Si) transmission and DX axles - if you don't have a header, you can use the exhaust manifold from the D15B2 and it will bolt right up to the DX exhaust - i would recommend that you get a good header for the 88-91 CRX/Civic Si and install a free flowing exhaust system all the way to the back of the car - use 2" exhaust as minimum, but 2 1/4" is preferred

 

[sinezter]

will any of these ecus work with the dohc zc i have?

P2E- OBD2 96-00 Civic DX, non-VTEC
P0A- OBD1 94-95 Accord EX
PM6- 88-91 Civic/CRX SOHC Si
PM8- 88-91 CRX HF

 

[Foreverbreathin]

I know that the pm6 will work just fine...i just recently did a swap and i did all the wiring my self...i think it was pretty easy...but i also studied the diagram for weeks before i did it...need some help feel free to ask

 

[sinezter]

where would i get a wireing diagram for my 89 dx? and was the dpfi to mpfi a hard converstion? i have the instruction on how to do it, and it seems prity strait forwarde, but iv never done it befor so just wondering

 

[Foreverbreathin]

4th Generation Civic Pages » MPFI Conversion


https://hondaswap.com/swap-articles/dpfi-mpfi-writeup-49557/

i thought these were the best two..this is everthing u need to do...just make sure u solder all connections..ull be sorry if you dont...also i studied it for a while first...but it aint hard at all i did it right the first time...

 

[sinezter]

also i have heard some stuff about the pm6 or other ecus like that will run the engine lean, is that true, because right now im just worryed about the swap working fine, and nothing getting dammaged

 

[Foreverbreathin]

Im not to sure about that...i can ask my machanic...he is a class a as the honda dealership...hell know for sure but i do know that it will work cause a pm6 is from a 88-91 si (mpfi)... which i think will work just fine but dont hold me to it cause i may be wrong...btw where r u from...if ur close enough maybe i can help..

 

[sinezter]

aight, that would be sweet if you could find out for me, and i live in las vegas

 

[jlicrx]

also i have heard some stuff about the pm6 or other ecus like that will run the engine lean, is that true, because right now im just worryed about the swap working fine, and nothing getting dammaged

the PM6 will not run the engine too lean - the ECU will adjust the air/fuel ratio based on readings from the O2 sensor - the main reason to use the PM7 or PG7 ECUs with the DOHC ZC is that they have a higher rev limiter (fuel cut-off) than the PM6 and the ZC runs a little better if you wind it up a little farther than the PM6 will allow

 

[Foreverbreathin]

well i havent talked to him yet but he sounds like he knows what he is talkin about...i would go with his advice...btw i live in philadeliphia..way to far but let me know how everything goes out... need anything else let me know...good luck

 

[ZCHONDACRX91]

I'm running a PM6 on my 91 crx with a ZC and it runs great, he is 100% right the PM6 has a rev limiter at 7,000 RPM and the PG7 is at 7,500 RPM and so is the PM7, but the PM7 has a speed limiter of 112 MPH, but you can buy a part to remove that. The only reason people think one ecu would run leaner or richer than the other is that the sensors differ in condition from car to car and the sensors (oxygen,MAP,exc...) tell the ECU what the AFR should be. If you try different ECU's on the same car you will see there is no difference, like with the PM6 and PG7.