91 Civic Si D16 to D15 swap?

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Thelostnet

New Member
Ok, why on earth would I swap a superior D16A6 motor with an inferior D15B? Because the D16 blew a ring. :(

So, I did the swap using the Si tranny, mpfi, harness and ecu. Everything bolted up perfectly and looks good.

But, when we go to start the car I get a blinking check engine light? wtf? No self-check, fuel pump doesn't come on. Check engine light blinks fast and continuously until I turn the key back off. The LED on the computer says the same story, blinks faster than i've ever seen one blink and never stops.

Maybe we connected something wrong? Got polarity screwed up somewhere? Fried the ecu? Maybe i'm using the wrong ecu? Though, I understand people have done a dpfi to mpfi swap on a D15 using the Si ecu with no problems.

Please help!? The real fun doesn't begin until I get my daily driver running and can start rebuilding that D16A6 for the real car. :)

Thanks!


-thelostnet
 
what ecu your running? PM6? or pm9? if your running pm9 it wont work, what is the throwing code number? dont swap d15b stay on d16a6 and fix the ring, d16a6 is much more power than d15b, im running D16a6 on my ed right now and i will swap z6 vtec head in a6 and this shit gonna be more quick
 
Thanks for the feedback, but the ECU is a PM6-A09. It's also not cycling a code, just blinks continuously. Someone told me they do that when you plug a diagnostic reader into them, but I don't have one of those.

This car isn't worthy of a well-built D16. The D15 is going in because it was cheap and available when my engine blew. My cousin has a nicely built Honda Civic with fancy suspension under it that's missing an engine. Were gonna rebuild this D16 and give it vtec before dropping it into his (soon to be mine) much nicer car.

Pulled the head off the blown D16 and snapped a few photos if you wanna see what a cylinder shouldn't look like.

You can see the scoring on cylinder 2 and 3 here.
IMG_0087.JPG

You can see the rounded edge on piston number 2 here. I think a chunk of skirt may have come loose to allow it to wear like that. Hopefully the crank and lower end are still ok.
IMG_0088.JPG
 
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Yeah, I read in a forum somewhere that people swapping their D15 to MPFI had to use a distributor from an Si. So, I used the distributor, MPFI intake, tranny and everything I could from the Si. I did keep the head on the D15 as it didn't make sense to swap them (though, the D16 has a hotter cam doesn't it?).

I'm sure we just screwed up something simple and there is a plug not connected to anything in the engine compartment somewhere... I'll find it eventually, but if anyone has any suggestions on where to start looking.
 
Yes, the D16 has a more aggressive cam(it would be wise to swap it in too since the ECU is tuned for that).

Maybe bad relay? It cranks, correct?
 
Good suggestion on the cam. Shouldn't be too big a deal to swap that in, but i'd like to get it running first.

It does crank and sounds fine, but doesn't get fuel. Relay is the next thing to check isn't it? But, I R tired and will do it after work tomorrow... Just odd that the relay would suddenly stop working when it worked fine with the old engine a couple weeks ago. Easy enough to check though.

thanks for the suggestions!
 
Well, that happened to me; twice. Both on my old CRX and my current Civic. It's pretty simple to fix but if that's not it; could be wiring issues and wrong sensors connected(has happened to me; resulted in burned out EACV circuit).
 
It Runs!

There was a little grounding wire back behind everything in a difficult to reach spot. Connected and fired right up. :D

The computer has been flashing some interesting codes and the check engine light is on. First was the MAP sensor. Disconnect, Reconnect, Reset and it went away. Then, after 20 minutes or so of driving the computer indicated a problem with the O2 sensor. Same solution didn't work so I guess I need a new o2 sensor.

Thanks for the great suggestions! I'll swap the cam this weekend and I think it'll be hard to tell the difference between the 1.5 and 1.6. With the Si tranny and MPFI that little motor does pretty good. Won't win any races, but still fun to drive. :)

I'll start a new thread in a week or so for the 1.6L engine rebuild.

Cheers!
 
Yeah theres big different between 1.5 and 1.6 i just swapped D16a6 si w/ si tranny feel bigg different and i sold it and this kid totalled that day i sold him =/
 
D15 vs. D16

I don't think there is much difference between D15 and D16 block as far as performance. Though, my perception may be skewed as my D16 wasn't actually running at peak performance prior to this swap (see above photos).

But, i've driven a stock D15 with the DPFI and DX tranny and they are slow. My new setup with a D15, MPFI and Si tranny is not slow. Would be interesting to dyno it sometime.

The point is that I think the tranny and MPFI make a bigger difference than the block. -my $0.02
 
I don't think there is much difference between D15 and D16 block as far as performance. Though, my perception may be skewed as my D16 wasn't actually running at peak performance prior to this swap (see above photos).

But, i've driven a stock D15 with the DPFI and DX tranny and they are slow. My new setup with a D15, MPFI and Si tranny is not slow. Would be interesting to dyno it sometime.

The point is that I think the tranny and MPFI make a bigger difference than the block. -my $0.02


Well I had d15b2 dpfi and it was maddd slow, when i swapped D16a6 si and i feel BIGG DIFFERENT no shyt
 
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