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Discussion Starter · #1 ·
So I just recently got into the Honda scene and what better way to get in it with a 99 Civic DX Hatchback. I recently bought it and found out it doesn’t have the right engine. The original engine has it D16Y7 and it had D15B7 in it. To do that kind of swap wouldn’t you have to change it from OBDII to OBDI? And would I have to get the D16Y7 engine, wiring harness and the ECU? Just trying to change it back to stock, thanks guys look forward to hear the responses.
 

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Discussion Starter · #3 ·
Yea it runs fine, idles a bit high and the code comes up as the idle air control valve. I’d replace it but I know the idle air control valve on the D15 and D16 are different. I don’t know if I’d work if I used a D16Y7 IAC (it has the stock throttle body I believe). Another thing, is that I live in California, the car wouldn’t be able to pass smog because it has an older generation motor. Luckily for me, I don’t have to smog it for another 8 months so I was wondering if I should swap it back right now so it can save me headaches down the road.
 

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BATSLOMAN GIVES NO FUCKS.
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is it a b7 with a y7 head? or is it a complete b7?
 

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BATSLOMAN GIVES NO FUCKS.
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what ecu is in it? is the dist jumper harnessed?
 

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Discussion Starter · #7 ·
I’m not sure, I’ll have to check when I get home; I do know that when I bought the car the D16Y7 ECU was in a box in a trunk lol so I’m guessing it’s not the OE ECU. I don’t know if the ECU that the car currently has is OBDI like the D15B7’s ECU would be. I’m pretty sure it has an OBDII harness because it still reads coded with an OBDII scanner. If that makes sense lol
 

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Grab some pictures. It might be a full d15b7, but maybe it has all the d16y7 manifolds/exhaust on it.

Does the intake manifold consist of basically curved runners with the throttlebody pointing to the sky? or does it have a plenum on it and the throttlebody facing the passengerside?
 

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Discussion Starter · #9 ·
So it’s definitely a full D15B7, as for the intake manifold and the exhaust manifold, they’re from the D16Y7 so it still has a catalytic converter and the throttle body points straight to the sky with the a short ram intake that I put in because the old one was shot. Its odd because I also checked the ECU and it’s from a 99-00 Civic.
137217
137219
 

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Discussion Starter · #10 ·
If that’s the stock ECU then does that mean it has the stock harness? Or does that change when you replace it with a D15?
 

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Sounds like it is merely a d15b7 directly in palce of the d16y7, with ALL the d16y7 electronics, ahrnesses, etc...


If you want to keep things nice and factory, find a good d16y7 and swap it in. you will get better fuel; economy, better power, and better reliability, as the d15b7 wont be drowning in fuel anymore.

Since it is manual, you can simply buy an OBD2B to OBD1 adapter harness, and run the factory P06 OBD1 ecu for the d15b7, and you will simply lose your ability to scan for codes via teh scanner.

The conversion harness and ecu swap will ALSO require switching to OBD1 fuel inectors from ANY normal civic, as in DX/LX/EX.

The conversion harness MAY have you repin it to deal with the IACV, since no OBD1 vehicles were 3wire, but you can simply repin the wiring so it goes from PWM (pulse width modulation) to standard voltage range 2 wire.


I personally recommend finding a d16y7. It will be the easiest method to your situation as far as only needing one thing swapped.

BUT that enables a cliff hanger in this series of interesting events. Do you do the timing belt, water pump, and various oiul gaskets as well? Would be the best time!
 

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Discussion Starter · #12 ·
Thank you, yea I can smell the unburnt fuel lol. I’ll be on the lookout for a good, low mile D16Y7. That’s going to be difficult lol.
 

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For the time being, you can certainly borrow a timing gun from someone, and you can loosen the distributor, and advance the timing a little bit by putting the car into service mode with the jumper AFTER the car is warmed up til radiator fans kick on.
It will help burn some of the extra fuel while giving you simultaneously a little extra power and fuel economy. Dont go nuts. factory d15b7 is 12degrees I think, and 14 degrees on Y7. Actually, check for the sticker under the hood, it will list a spark plug gap (probably in metric, 1.0 to 1.1mm). take that base timing number on the sticker, and you should be able to get another 1-3 degrees. Then baby it for awhile until the computer is a bit happier, or better yet, yank battery NEG off for 5-10 minutes to reset ecu and let it re-adjust during the first few driving cycles!

You can also check your spark plug gaps, and make sure they are clean as well. Just give the engine its best shot at being happy in case it takes a while to find a nice d16y7.
 
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