LAE101

Just sawpped a JDM D16A SOHC from a 96-98 japan civic fiero chassis EK5 or EK8 (this is not the 88-91 civic/crx SI d16a6,a1,a8,a9,etc..). The motor is listed as equivenent to the Y8 by the JDM source and the block may be stamped with D16A or ZC from japan. Our problem is a lag in power band before the vtec kick in. The Y8 vtec kicks in at about 5500 and there is a big power loss in the D16A from about 4800 until 5500 when the vtec kicks. I think that the D16A (ZC) SOHC vtec is the same cam and head as a USDM D16Z6 and is cammed for vtec at about 4800.

Can anyone confirm this as the case and if so, can we drop in the cam from the removed Y8 (head is good, botton end spun bearings). Any help would be great to eliminate the bogging between 4800 and 5500.



Modified by LAE101 at 8:36 AM 1/31/2007

suspendedHatch

If it's from a 96+ Civic, it's an OBD2 head, in other words, the equivalent of the Y8. In that case you should be using a Y8 ECU and you should run the VTEC solenoid wire to the ECU. There are two connections at the ECU on a USDM ECU, and only one on a JDM ECU (at least, this is the case with the OBD1 engines, I'm not sure about the OBD2).

If the head is in fact from an OBD1, you'll need to convert your car to OBD1 and use a P28 ECU. You'll need to wire VTEC as well.

Does the head have one VTEC solenoid or two?

LAE101

Thanks for the reply.
The car is a 97 EX with the Y8 ECU and setup so its OBD2a for sure. I swapped the IM, all sensors, and the vtec solinoid from the Y8 onto the D16A, all wiring and plugs therefor OK set and no wring needed to be done. There is no CEL and no codes.

There is only 1 vtec solinoid on the engine.

The JDM D16A is from a 96-00 Japan fiero model rti. So, there is no problem with vtec, it is working fine once it hits 5500 rpm, the problem is that there is a bad power loss between 4500 and when the vtec kicks at 5500. Everything seems normal.

So far, the only reason I can come up with is that the D16A cam is not the same as the Y8 cam and is not producing power all the way up to the 5500 when vtec kicks. If the cam is like a D16Z6 in the JDM, that would explain the problem since the vtec on a Z6 kicks at 4800.

We are tring to confirm if the D16A (sometimes stamped ZC) from 6th generation SOHC JDM vtec models are cammed like the Y8 or Z6 US motors. If they are we are wondering if the Y8 cam will fit the D16A or do we have to swap the whole darn head?

ridin98civic

i know the y8 cam will work in a z6 motor, its just a few degrees off

LAE101

Hey thanks, thats encouraging, we are going a to try the Y8 cam into what appears to be a Z6 cam beacuse the D16A SOHC VTEC behaves that way. The cam sproket and key are identical to the Y8 so we may not be off like the key on a real Z6. Dunno.

Hoping this will work and it really is the problem.

jsmatson91

I know I'm late, I'm sorry. But I need to know if that worked. I'm having the exact same issue. Except I'm in a 98..