Ok....here goes. I have searched but did not find anything like my situation. Sorry if I could not find it. My son bought a 1990 Civic SI with a 1996 1.6 L D16Y8 Vtec in it. The motor went out on him and he bought a 1995 1.6 L D16Z6 and had a friend put it in. The motor will not run right. It will not run over 3000 rpm. I am assuming this is because the OBD 1 vs. the OBD2. He has a VTEC controler in the car. I need to help him get back on the road. I understand there is a difference in the distributors in these motors. We have tried to put the Y8 dizzy on the Z6 but the bolt pattern is different. Can this be modified? The car ran great with the Y8 but now runs like crap. I have read some of the post here, and I think there are some very smart Honda people on this page. I am an old muscle car guy that really needs some help. Can anyone give me some ideas on how to fix this mess my son has himself in? I know how to turn wrenches, but I don't know Hondas!! Thanks in advance!!!
Help a noob out please!!
- Thread starter sdj02
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Here is a pic of the ecu. It is kind of blurry, but I think you can see all the numbers. Thanks for the help!!
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daveholiday
Do work
I'm not positive because ive never had to swap an ecu but i know the z6 motor's ecu is a p28, see the pm6 in the middle? That's the ecu code, and thats for the y8. Did the new motor come with an ecu?
New motor did not come with ecu. Still trying to use the pm6.
daveholiday
Do work
I'm not sure if that'll work due to different fuel maps, along with other differences in the ecu. Get a p28, use a conversion harness to go obd1>obd2, or maybe it's the other way around. I'm sure someone on here will correct me. It's one of the two, but you need a p28 regardless.
D16SiHatch
Active Member
he needs an obd0 to obd1 harness not 1 to 2. the car is obd0 which explains the pm6 a6 Si ecu. The motor is an obd1 z6.
Well he tried using the ecu that was in the car the z6 came out of. He said it was an obd1 computer. When he hooked it up his car would not even start. Can someone point me in the direction of how to hybrid a z6 into a 1990 Civic SI 5 speed with the obd0 ecu? This might be my easiest route is to just start over. Thanks for all of the tips.
D16SiHatch
Active Member
Well at this point if you dont have a conversion harness then you don't even have a way to hook up your z6 distributor. So that being said i'm curious as to how your hooking up whatever dizzy it is that you're using. The stock obd0 harness that your using on the z6 does not have the proper connections to wire up the obd1 distributor. With the conversion harness it will come with the two harnesses needed that convert the two dizzy plugs from obd0 to obd1.
It sounds like whoever owned the car before half-assed the D16Y8 swap. I'm guessing they just used the car's original ECU and ran it as OBD0 rather then converting it. That would also explain the VTEC controller.
That method is considered pretty old school at this point, and it's not really ideal. The best way to go about this is to buy an OBD0 to OBD1 conversion harness and then use the appropriate OBD1 ECU for the D16Z6. That ECU will operate the VTEC and also run the motor optimally, and then you can just ditch the VTEC controller...
That method is considered pretty old school at this point, and it's not really ideal. The best way to go about this is to buy an OBD0 to OBD1 conversion harness and then use the appropriate OBD1 ECU for the D16Z6. That ECU will operate the VTEC and also run the motor optimally, and then you can just ditch the VTEC controller...
I asked my son how the guy got the Z6 to hook up to the old Y8 harness, and he said the guy " modified" 
the harness to work. I am sure this is the whole problem now that I know the whole story. I am not sure where to go from here. I guess I will have to buy the obd0 to obd1 adapter, the obd1 ecu, and a new harness. Or I can just steal my kids car, and scrap it!! I also just found out it is throwing a 4 and 8 code. Does this help or am I still screwed? 
Thanks for all of the info.
the harness to work. I am sure this is the whole problem now that I know the whole story. I am not sure where to go from here. I guess I will have to buy the obd0 to obd1 adapter, the obd1 ecu, and a new harness. Or I can just steal my kids car, and scrap it!! I also just found out it is throwing a 4 and 8 code. Does this help or am I still screwed? Thanks for all of the info.
Last edited:
George777
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CKP Sensor (Crankshaft Position Sensor)
defective circuit or unplugged / defective sensor
8- Accord Civic CRV CRX Del Sol Odyssey Prelude
85-98 86-98 97-98 85-91 93-97 95-98 85-98
TDC Sensor (Top Dead Center)
defective circuit or unplugged / defective sensor
90-98 88-98 97-98 88-91 93-97 95-98 85-98
CKP Sensor (Crankshaft Position Sensor)
defective circuit or unplugged / defective sensor
8- Accord Civic CRV CRX Del Sol Odyssey Prelude
85-98 86-98 97-98 85-91 93-97 95-98 85-98
TDC Sensor (Top Dead Center)
defective circuit or unplugged / defective sensor
