run a y7 on a y8 computer

[mucci2k]

Is is possible to run a D16Y7 non-vtec motor on a D16Y8 vtec computer and wiring harness?

[kommon_sense]

no.

[mucci2k]

I have a y7 running on a p2m ecu, runs really bad, can I just change the ecu out for a p2n or a p2e and keep the current wiring harness?

[kommon_sense]

Can you explain your setup better. what chassis? what ecu did the p2n come from? I thought that the p2e *was* the y7 ecu.

[klungemonger]

The P2E is a Y7 ecu, you just need to make sure it is of the same OBD version (96-98 or 99-00) as your car. Any other ecu will not properly operate a Y7, in large part due to the odd 3-wire idle control valve. the only other model with one of those is the Y8 automatic, but then that ecu you will have to deal with the automatic crap, knock sensor, vtec circuits, etc which will all go into fault mode since they are missing on the Y7. A P75 (Teg LS) could possibly run it but you'll get faults for the idle valve and the incompatible crank flux sensor.

[mucci2k]

I found out after buying the car that the previous owner swaped in a 99 d16y7 motor into my 96 ex. So I have figured he some how got the original computer and wiring harness to run the d16y7 but the engine light flashes and its is very slugish below 3000 rpm. So from my understanding I am running a d16y8 OBD2A computer on a d16y7 engine that is looking for a OBD2B computer. I am trying to figure out what to do to get it running normal.

[klungemonger]

The engine doesn't care if it's OBD2A or OBD2B, that only matters to the engine harness because the ecu plugs are rearranged. All the sensors and plugs on the engine side are the same between the 2. Can you get the part number off the side of your ecu and post it up here so we can verify what it is for certain? Also you are definitely certain you have a Y7 engine...most D16 motors are somewhat sluggish below 3K anyhow so that's not the best measure to go by!

[mucci2k]

Here is a pic of the ecu. I will check the front of the block again tonight.

[klungemonger]

Well that explains at least a portion of your problems...you have the ecu from an HX automatic w/CVT transmission (d16y5 engine). That's the VTEC-e engine.

You probably couldn't get a more mismatched ecu! Is the car manual or auto trans?

[mucci2k]

automatic, that would explain why it works better when I manually shift through the gears.

[klungemonger]

Yeah the CVT is not like a regular auto trans. Even a Y8 automatic ecu would be better than that one. The HX also will run the engine crappily because it requires a 5-wire wideband O2 sensor on the primary O2 branch...you probably have the standard 4-wire which means the ecu will have a hard time metering fuel properly, not to mention you are probably very lean below 3000rpms, for 2 reasons: first, the Y7 has 180cc injectors, instead of 240cc like the other models. Second, VTEC-e generally runs only 1 intake valve below 3K-ish to save fuel. So kind of a double whammy there. Get rid of that ecu asap. I can't imagine you'd pay more than like $25 for an auto Y7 ecu, it' s a tough item to get rid of if you don't need it.

[kommon_sense]

Seems like you would have about 30 different CEL's with your current setup.

[mucci2k]

I checked, I have a d16y7, as well as 4 wire o2 sensors.

[klungemonger]

Yeah you gotta swap that ecu asap. Put a call out on all the forums for a 96-98 P2E automatic ecu you'll be in much better shape.

[mucci2k]

would a P2E-A72 work? found a cheap one on ebay.