Forward
- I'm the dummy here, I'm racking my brain looking at diagrams, pinouts, etc, to where I feel less confident the more I overthink it.
- Yes I know what Vtec-e is. I'm not looking for (more powa, vtak yo!!!) I have a 91 CRX si ls/vtec for that.
- Yes I realize all the extra work for possibly a few extra mpg's may be overkill. I stockpiled a bunch of vx stuff and the 88-91 chassis are my favorite.
- Yes I realize that an 89 lx 4dr isn't the best/lightest chassis for this swap. I'm dealing with what I have available.


My Goal
- My goal is to not only have a D15Z1 powered 89 lx, but to have an extensive thread for anyone thinking of taking on or performing this swap. I plan on taking lots of pics, and relaying any and all info related to this swap to the final results.

...And here we are
Ok so I haven't touched the wiring yet. Everything is still completely stock. I have the engine/trans ready to go with the DPFI harness wrapped around ready for modifying. I'm using this link http://www.crxmpg.com/ and other DPFI to MPFI, DPFI to OBD1 vtec, OBDO ecu pinouts, and OBD1 pinouts as references.

I have an OBD0 MPFI to OBD1 vtec subharness and additional OBD1 ecu pins to add the necessary wires for the vtec-e system.

I have soldering tools and experience so I'm confident that I can make secure connections.

I have all the necessary sensors, vtec-e related stuff to make this happen. (5 wire 02, firewall egr, catalytic converter, ecu, etc.)

I'm really looking for help dumbing down some of this, I'll elaborate more tomorrow as it's getting late and I need to crash. Maybe I just need to hear (read) things worded differently to get it right. As of now I just feel scatterbrained and think I'm trying too hard to understand it. Again I am dedicated to this thread and want it to be as informative and resourceful as possible.

Thanks in advance to anyone willing to help, negative comments will be ignored.

 

reserve post for "hopefully" very detailed write up

 

I saw a pretty good write up on this once before. The VTEC-E motors are good for the MPGs. No doubt about that. But didn't they make a 1.3L in the 80s that was a MPG monster? I think it was carb'd though. I'll try and find that write up to give you some more info.

 

That'd be awesome if you could find it, anything related to this swap could be beneficial to not only me but anyone who comes across this thread.


Today I made alot of progress matching sensor wires to their respective ecu wires. I have a stock set of 92 vx ecu plugs that I pulled out of one of my parts cars to use as a guide for the wires I'm going to have to add to my OBD0 to OBD1 harness. Here's a couple things I noticed...

-On my ecu jumper, coming from the OBD0 side, I have one wire from A12 and one from A14 (Main relay). These two wires are spliced together before the OBD1 plugs and are ran only to A7. A8 is left empty. My stock vx ecu plugs have GRN/YEL wires coming out of A7 and A8. One OBD1 ecu pinout lists A7 as fuel pump relay and A8 as empty slot. The sensor wiring schematic in the crxmpg link has A7 listed as FLR1 and A8 as FLR2. Should I undo the splice and run one of the wires to A8 instead of both going to A7?

-My vx plugs have a wire in slot A16 (alternator control). On my jumper this slot is left empty. What?

- Vx plugs have a wire in A22 (Ignition control module). This slot is empty on my ecu jumper. The wires coming from B15 and B17 (Igniter Unit) on the OBD0 side are spliced together before the OBD1 plugs are ran only to A21. Again should I undo the splice and run one of the wires to A22?

- Vx plugs have a wire in B7 (M/T clutch switch). This slot is left empty on the jumper. I'm pretty sure this car had a clutch switch and was already jumped. Do I just find which wire (of the two) that isn't the ground and run it to B7?

 

This guy did the swap I believe:

https://honda-tech.com/forums/hybrid-engine-swaps-18/obd2-d15b-3-stage-vtec-e-into-91-civic-swap-gurus-assemble-2370188/

Robbing some more quotes:

It seems like a MPFI DX motor and a 4-speed trans would be easier and get the same mileage without the hassle of VTEC-E and the 5-wire O2.

 

I have done this swap in my 91 hf not hard really...my beef is lean burn has its problems mine actually runs rich at times and fouls the plugs...I run no cat so a heated object in front of the o2 may help it stay heated...I also have the even taller hf trans ive never got less then 42 no more then 50 though and they hesitate buck when going into lean burn...I did get 47 mpg going from chicago to fl.i got that the whole way down doing 75-78
Have any question just ask.thinking about selling it reliable just want something diffwrant

 

no cat? can you elaborate? what exhaust manifold are you using? I'll using the stock vx manifold and cat on this swap.

I'm really not trying to get the craziest gas mileage, just want to get all the electrical components of this swap down. I get 48-51 in my 93 vx and I got 38 in the 89 4dr before the motor blew. I'm really just doing this to have both my dd's on the same engine/electronics. I should the swap buttoned up tomorrow so I'll get to see where I stand shortly.

 

Running a vx manifold. Running no cat you think id get better mileage no restrictions but that vx mani you know how the cat is right up there like a turbo.it keeps the o2 heated that vx ecu seems to need that since its a wideband ecu to maintain a proper a/f ratio and to stay in lean burn etc...
Wiring was not an issue 0-1 harness no need to do pinout stuff.

 

Get an obd0-obd1 harness made to wire up to a vx motor thats what I did.I called boomslang has all your extras you need to solder up the 7wire o2, vtec, egr. Your making it way more complicated then it is.
First convert dpfi to mpfi then do your obd0-obd1 conversion it should be a piece of cake...

 

Hardest part is the O2 sensor it uses. I thought it was a 5-wire O2? But it's a 7-wire. Geez.

 

Its a 5 wire o2, connector looks like a 7 pin.. Make sure you get the correct o2 for it ill look up the number. I have the ntk one it was 200 and is a 5 wire wideband one. Believe I got it from oxygen sensors. Net

 

$200 is some major bucks. I've been told that some of the more basic non-vtec MPFI swaps can get very similar gas mileage with less headache.

 

Wiring it up wasnt bad, I'm just more concerned with the ecu side of things. I had a OBD0-OBD1 subharness that I was adding the vtec-e wires to. I have 3 5 wire o2's here to try. Everything is hooked up, just have to add fluids. Going to work now, I'll try and start it tomorrow morning.

 

If you truly want to wire up the z1 correctly you will also need to wire in the black box, a/f and egr valve. Which a/f will depend on which ecu you use. From my understanding federal emission ecus have a 7 wire a/f snd California emissions are different (5 wires)? Correct me if im wrong

 

So everything is back together and she started right up on the first try. I am getting code 41 (go figure) for the O2, but the egr system is fine. I tried both spare PO7 ecus and still the same. I'll try another O2 just to be sure but looks like I'll be double checking my wiring. Other than that I'm stoked, car runs and idles great so far. Took it around the block and it did fine.

 

Pics or it didn't happen.

But congrats. Good to hear it's running. Probably is your wiring. Triple check that.

 

You wired in an air fuel sensor and not a standard 4 wire o2 correct?

 

Yeah, I ran all 7 wires to the harness plug. I tested a couple of my 5 wire o2's in my 93 vx to make sure they were good. I think I mixed up a couple wires, just haven't had a chance to look at it due to work.