D15B2 to D15B vtec & mpfi swap question. I did search first.

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Danno

Junior Member
Hi guys, this is my first post here. I've searched high and low all over the net, and can't find the answers I'm looking for, so here goes.
I just did my first honda motor swap, nothing major. I went from a D15B2 in my '91 hatch, all stock including the dpfi, and installed a D15B vtec motor.
I took the motor out of another car, so I kept the engine harness and some of the body harness where it goes through the firewall, and hooks to the ecm.

The car it came out of was a '91 DX, same as mine, running obdo, and a VAFC. The ecm is a chipped PR4 (88-89 integra?). I'm not certain what the PR4 is chipped to do, except that the revlimiter is 7800 and the a/c pin provides vtec. I'm not using the PR4 to engage vtec, I'm leaving that to the VAFC.

To simplify the swap, as stated above, I used the engine harness off the b15b, which is a stock '91DX harness converted to MPFI, with a Vtec sub harness, and copied the ecm pinouts from the ecm side of the harness in the same car. This way I didn't have to hack the body harness and ecm plugs too badly in my hatch. The car runs, and runs rich, but has a constant code 13, and a contant check engine light. Vtec works fine aswell.

I'm a bit confused about wiring the vafc, namely the pressure signal input and output. I'm assuming these wires have to be tied into the pressure signal from the map sensor. Even without hooking up the vafc signal wires I still get the code 13. Would the MAP sensor wires to a PR4 ecm be different that that of my stock PM5 ecu? I'm almost certain my check engine light is cause by a wiring issue.

The three wires from the MAP should be 5 volt feed (yellow/red) pin C15, sensor ground (white) pin C11, and map signal (green/white) pin C11, should they not? And if so, I should be hooking up the vafc pressure signal input and output wires inline with the signal wire. Before I go much further I want to address the code 13 issue.

I'm not certain where to go next. I also have a PM6 ecu if that would be better suited to this swap.

I know that an obd1 and P28 conversion would be the best way to run and tune the car, but its just not in the budget right now.

Thanks,

Dan.
 
Thanks... I just didn't want anyone to think that I was an ignorant noob that was too lazy to research my issue first.

Took the car out for the first rip with the new motor and MAN what a difference from the dpfi d15b2. Night and day. I cant wait to solve the check engine light and start playing.

I did get the VAFC wired up correctly, and now I can see correct pressure readings. But I'm sure there are more gains to be had once the ecm can recieve and interpret correct map values.
 
Got it figured out.... noob mistake. Runs like a champ now.
 
i have a 91 integra...ls/vtech and can't get vtec to kick in....i have ran the wires....i have power to the soloniod and pressure switch.....91b16 ecu.....i have the right amount of oil......can anyone help me out
 
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