pmjr0987

Hey guys

My fiance has a 2002 civic LX coupe automatic (240k miles non-vtec) that the transmission just went on

I got a rear end crashed 2003 civic EX coupe automatic (130k miles with vtec) for the parts car

I got the engine and transmission out of her car, and im getting ready to pull the motor out of the EX parts car tonight or tomorrow to put into her LX

The question is, and i know its a bit late to ask lol but how compatible are they?

Am i going to run into any surprises with the vtec motor into the non vtec car? Any differences between the years since they are a year apart?

If it needs the computer to be swapped is there anything that needs to be programmed for that to happen, or should it just bolt in and go without swapping the computers?

SeAmUs_MaCk

Just bolt on and go....the TB/IM are probably different on the non-vtec motor but..just swap everything from one to the other...you could leave the motor in her car and just put the EX trans on....but if you are capable of doing the whole swap then do it....i think the non vtec motor is better for MPG....and then LX trans is geared lower then EX....so she may use a few...like 2-3 mpg from the swap...but much better acceleration. Make sure you swap ecu.....if you use the same engine harness your going to have to run wires for vtec...and also IACV if I'm not mistaken.....Or just use the whole engine wire harness from EX and you won't have to run any wire....If someone wants to correct me on the IACV wiring or not for the 7th Gen...cause like i said I'm not sure...but 100% on the VTEC

ezone

If you go with the complete swap including PCM there will be an issue with getting the keys programmed before it will run.
I see 2 possible ways:

You could swap the column lock assembly, complete (less the actual electrical ignition switch), to your good car. Now you'd have to use more than one key to get in and drive it.

OR
You could split the column covers off, get the ignition switch complete off the parts car and take it apart, connect only the parts car immobilizer ring to the good car, stick the parts car key through the immobi ring so it can be "read". (This fools the PCM to think it has the correct key and will let the engine run.)

Once it all runs like you want, then get your keys and immobilizer programmed to the new PCM so you don't have the stray immobi ring and key hanging out.





On the rest, get a couple wire diagrams and see what's different between versions.

SeAmUs_MaCk

Instead of doing all that....buy a blank key with a chip online for $25 and have it programmed at the dealer...Or 2-3 So you have a spare....the key fab may or may not work....i know on the 6th Gen civics it was controlled by the Stock Radio...the key fab may work through the ECU on 7th gens instead of the Stock Radio....Then obviously have it cut to match the LX key....They may be able to re-program the current keys....but I'm not sure about that....You can run the LX ECU until you get the keys cut and programmed....It won't run the way it should....the fuel maps may be different, and it won't run vtec....but it will do damage to the engine if you run the wrong ecu for too long....but if you drive it to the dealership after the keys have been cut with the LX ecu....swap the EX ecu while your there...then have them program it...and you'll be good to go!...It won't take them that long to do. Good luck.

pmjr0987

ok thanks guys. I was thinking about that key thing and getting it programmed to the EX ecu while having it cut to the LX's pattern. Ill give them a call tomorrow and check prices

I got both engines removed and on dolly's a few days ago... New timing belt n water pump going into the EX motor while its out so next up is tackling the wire harness swap

So as far as the wire harness, how much gets removed? i see for the most part there is a removable fuse box by the battery and then it all goes through the firewall into the dash by the glove compartment. Im guessing that the ECU should be under there so dismount and remove it than just pull the harness back into the engine bay dismount the fuse box than thats? are hondas really all this easy to work on? lol

ezone

I probably would have left the harnesses attached to the engines and disconnected everything else.


You already have keys for the car, you just need them to work with the new PCM. Right?


Pop open the glovebox as if you were going to change cabin filters, the PCM is right up there standing on edge by the top of the fan housing.
You will need to remove the glovebox and cut the plastic cross brace in the glove box opening, then remove the metal brace behind that to get the PCM out.

pmjr0987

good idea on the harness, ill attach the EX harness to the motor while its on the dolly to save some headache.

I do have keys for the car, i have titles for both, as well as the keys for both. IDK if they ask for titles but maybe that will make things easier.

So just to clarify i install the EX harness/engine/trans/ECU to the LX and than take the LX's key and have it programmed to the EX's pcm?

As well, im looking more at the harness and notice it goes into the firewall in anotehr location, lower by the foot well, as well as around into the front bumper on both sides. when i look up harness's online i dont see nearly as many wires. does that part seporate from the rest of the harness or do i have to pull the carpet and remove whatever its plugged into under that, as well as the front bumpers and pull all that crap too?

man she owes me big time

kinakoes2

Start at 4:24 XD

ezone

Yeah, but you have to drive it to the dealer to do it. That's why you leave the LX PCM dangling out but still connected, because it will run the engine and you can drive on it until you get the programming done with the LX key and the EX PCM. (assuming this works in real life as good as it does in my head, LOL)



I'd start at the PCM.
The engine harness should have something like 3 connectors in the PCM (A, B, C), plus a harness junction right in front of the PCM.

Connector E stays in the dash, it's part of the dash harness.





There is another harness junction by the firewall.....total 5 connectors in the dash side of the firewall. Feed all these out through the hole in the firewall.

The rest of the engine harness should be in the engine compartment.



What I can't tell you from here is if all the extra wiring (harness junctions) is still the same between the year and model differences.

pmjr0987

thanks for the illustration, thats exactly what i see in the glove compartment. it looks like the harness goes into the firewall bellow that as well but idk where that terminates until i rip the carpet out

Im thinking of a new plan...

Since i want to do the head gasket anyway, what about just taking the heads and swapping them and forgetting this harness crap? i know the EX block will have 130k miles at least and the LX head seems to be just fine. Ill throw some new valve seals in it to be sure. this way i do not have to swap harness, and do not have to worry about getting the key programmed either. I could care less if the car has 110 hp vs 127 hp, they are both slow as **** anyway lol.

some **** i read says the automatics LX to EX are different ratios but i thought they were the same? I thought only the manuals were different ratios, i cant seem to find any definitive info saying one way or the other.

Reason i ask is if i leave the harness alone, and just run the LX head on the EX block and EX trans but the ratios are different, i dont want to throw transmission codes or have the speedometer be off because the LX ecu cant handle the EX ratios... as long as the transmissions are the same, ill just swap the head and call it a day. Honda wants $180 to program the key, and they say they cannot guaranty it works or not, but have to charge regardless and i dont like that!

EDIT-

found this link, check out post #16 he says he swapped the EX to LX car and it worked fine... hoping he doesn't have his info confused lol

https://www.civicforums.com/forums/3...on-2005-a.html

ezone

I think we decided earlier that the EX block has slightly higher compression pistons. Other than that, I don't think there's a problem with the head swap.

I can't answer about the gear ratios....


$180 to program a key? Wow. Seems astro-freeking-nomical.
My dealer charges less than half of that, although I hear other dealers near us are higher.

pmjr0987

true, now i see it 9.5:1 for the a1 and 9.9:1 for the a2. I think it should be fine, maybe will even run better

I was shocked @ price, and he said he couldn't guaranty it would work. There's a big issue with that since the car needed to be back on the road just about last week lol

So far i got the a2 block with the good trans cleaned up and ready to install the a1 head. I installed new valve seals, in addition to the new head gasket, water pump and timing belt, cam and crank seals, thermostat and 100k miles off the suspension i think i squeezed a few more worry free miles from the car for no money after i sell off some extra parts... ill know Monday when i have time to finish it for sure

jcb111

I recently did a similar swap in my 2005 Civic LX, I put a 2003 Civic EX motor, trans, wire harness and ECU in.
Where to you wire the downstream O2 Sensor in as in the LX they were both in front. I already ran it down to where it needed to go, but all the wiring diagrams are different between both.
Any help is appreciated, car is up and running just check engine light is on.
Here are some details on the what has been done already

I recently swapped my D17A1 out of my 2005 Civic LX SE with a D17A2. I had the Motor, Trans, Wire harness and ECU from the donor 2003 EX. The motor is in and running on the stock LX ECU right now throwing the code for the 2nd O2 sensor, and no VTEC. I have an appt at Honda on Wednesday to have the ECU flashed to match my keys so I can get the VTEC working.

So in the mean time I have been searching all the forums for how to wire in the 2nd O2 sensor as the factory harness does not have it on it like on my LX. As I have read on all the forums the 2nd O2 sensor is part of the body harness. I dissected the harness from my old motor to get the wires for the O2 sensor. I have put the pins into the connector at the ECU where they were on the LX.
pin 25 wht/red Secondary O2
23 brn/yel Logic Ground
14 blk/wht SecondaryO2 sensor heater control
10 grn/yel Sensor ground

The last wire is Black/Yellow and I can't figure out where this wire goes. I think it would be pins 2 or 3 which are supposed to be yel/blk power source but not sure so I left it disconnected.

Checked for codes and now I have 8 with all these connected. It throws a code for both O2 sensors. When I take the Logic ground off it only throws the secondary O2 and heater code. So I tried the Logic ground on pin 24 which is also supposed to be logic ground with the same result, throwing 8 codes.

Am I having these issues because I am running on the LX ECU and did not flash the EX ECU yet?

The O2 sensors are new and for the EX motor not my LX O2 sensors, still using LX ECU at the moment.

I replaced the whole exhaust headers back with aftermarket, 1 O2 Sensor at bottom of header the other is about mid car under the console. Not CAT installed, but 2nd O2 is with spacer.

Where do I wire in the 2nd O2 Sensor at the ECU?
There are 4 wires and a shield

Not that it matters but also replaced while the motor was out
Timing Belt, Water Pump, Thermostat, Crank Seal, Cam Seal, Valve Cover Gasket, Both Belts, Spark Plug Seals, Output Shaft Seals, Clutch Kit, Motor Mounts, O2 Sensors, Full Exhaust, Cold Air Intake, All Fluids

Please Help if you can, I am not your average everyday idiot. I am a Tech by trade and have worked on cars for years. I have owned this car since new and haven't ever had to do anything but the usual maintenance. Haven't done a swap since the early 90's. I also have all the tools and testing equipment at my disposal.
Thanks Again for all your help
Jason (n00b)