Vx Ecu
 

Hi everybody. I'm new. I tried to search for this question, but couldn't find it.
My friend have a D15z1 engine, but his ecu is p28. It's giving out check engine light (Knock sensor). The question is what other ECU beside P07 could he use ? Thanks in advance, guys.

none, assuming he intends to use the z1 as if from the factory.

and unless the p28 is chipped with some aftermarket program in it and the board has had knock support added, he's not throwing a code for knock sensor. d16z6's do not have knock sensors so the stock p28 ecu does not look for it.

He had 2 check engine light, 1 was the code 54 (Crank Fluctuation Sensor), I spliced it with another wire, forgot which one, so there was no cel after that. After driving for a while, it throw code 23, the knock sensor. I can bypass that cel, but don't know if i should. I'm afraid there might will be misfiring, or mess up the timing. What would be some potential problems if he keep using the P28 ecu ?

It simply will not run correctly with a P28. The P28 was made to rev all the way to 7200 or so, while the Z1 has about a 6000 redline. The Z1 makes all it's power in very low RPM while the P28 is intended for engines that make max power around 5500 RPM. The fuel and timing calibrations are very different and peak at very different points. You'll get poor power, poor FE, you're going to foul and/or cook your spark plugs, you could get knock, you'll destroy your cat converter and your O2 sensor, and it will permanently be in limp mode.

Some late model OBD1 B series engines (using a P28) and possibly even the Z1 had a knock sensor. It shows up on P28 pinout diagrams.

Thanks guys. I was driving it last night, and it didn't have any power at all. I felt my stock CRX dx was faster than this. I gotta get that P07 ecu or else it'll mess up the engine. Thanks again guys.

A stock CRX DX is going to be faster than even a VX with the right ECU. Especially if it is the ultralight 1988 DX. But even the 1989-1991 DX (which is actually heavier than a VX) will be faster due to the more acceleration-oriented gearing.