Goran

Hey guys I really need some help with the engine me and my buddy did.

2003 Honda civic ex 5spd d17 vtec stock started messing up really bad knocking and all that bad stuff so I swapped the engine with the only only available to me which was from a

2004 Honda Civic LX automatic... engine works great now the question

I cant rev passed 4K RPM bc its looking for the Vtec which obviously is not there

I am fine with losing VTEC how can I make this car think everything is normal?

Do need an ecu from a 2004 civic non vtec and 5spd? or does the tranmission matter I would just like for someone to tell me the right way of fixing my current problem without swapping it for another engine or putting the old head back on ...lets just say I dont want the vtec ( I know sucks but oh well)
how make it happy is basically my question..

toyomatt84

iTrader: (1)

VTEC engages at 2700 RPM's, so that's not likely. It's probably displaying a CEL (Check Engine Light) and the car is in Limp Mode (cannot rev. past 4,000 RPM's).

You'll need a non-VTEC ECU for a manual car. An automatic one will post a CEL constantly.

Goran

OK that makes sense so here is an update on that ....

I replaced the ECU

I got one at a auto recycling place "junkyard" it was fairly expensive around 100 bucks but had a friend at the local honda dealership and he flashed my key over to the new ECU and viola lol I can rev past 4k now all damn day...


Something else that is not quite right that we found out right after is the O2 sensors different from 2003 vtec to 2004 non vtec go figure so I have a check engine light on for that but oh well will do that when I get into some more money unless someone here got some? lol


Thank you again

toyomatt84

iTrader: (1)

For your O2 sensor problem:

Either run the VTEC manifold, catalytic converter, and midpipe...
-or-
Run the non-VTEC manifold, catalytic converter, and midpipe.

Either method will clear your O2 sensor problems, since both bolt up to the head and the axle-back portion of the exhaust the same.

Targa250R

No, it won't clear the problem. The exhaust configuration is not what is causing the O2 sensor codes; the sensors are physically different. Honda switched from a narrow-band heated primary oxygen sensor in '01-03 models to a wide-band air/fuel ratio sensor in '04-05 models. '01-03 D17A1, '04-05 D17A1, '01-03 D17A2, and '04-05 D17A2 all use different primary oxygen sensors. The ECM looks for a specific type of signal, and if the correct sensor isn't installed it will throw a CEL.

Goran, you will need a Denso 234-9005 primary sensor. A fair warning, these are not cheap - but nothing else will work correctly, so you don't really have a choice. The secondary sensor signal is the same between '03 EX and '04 LX models, so you won't need to change that one.

toyomatt84

iTrader: (1)

I read it as a piping issue, which is a misread on my part. Listen to Targa, he knows his stuff.

Goran

ok so let me get this straight the o2 sensors are physically different? so I get the 04-05 sensors they wont work? what else would I have to change out?

Goran

I am sorry disregard last message i didn't see the last part... so just the primary sensor sounds great to me thank you guys so much

Goran

Here is my question just looked up some stuff on that part it says it fits all of the 01-05 civics so why would it be different than the one I have now? I found them on the internet 100-150 bucks I can live with that just wish I knew it would fix it for sure but I have faith in you toyomatt84 so I will go ahead and get that one and hope for the best if not oh well I got a new o2 sensor no hard feelings either way....

One thing tho at the dealership I got a buddy when he hooked up my car to the computer it said both need to be replaced?

Targa250R

Anything that tells you that is 100% wrong. Ask me how I know.

What codes were stored? Did he give you a list? Post all of them here.

Goran

I will try and get them but the scan tool said both needed to be replaced as far as I remember maybe I can stop by auto zone or somewhere and see if they will hook it up for me ....

should be sometime tomorrow...

thank you again this forum rules !!!

Mechanichelp

Hello, I know this is an old thread but I've got nearly the same issue. I'm a mechanic helping out a friend. It's an 02 civic 1.7 vtec 5 speed. Motor blew. Could only find a non vtec engine of same year. Swapped it and the PCM, reused the vtec harness (cause non vtec harness was destroyed when removed). Motor runs fine but is setting a hard fault for PO141-O2 sensor 2 heater circuit. So my friend eventually got the right harness (non vtec of same year). Car still runs fine but now has two hard faults PO141 and PO135-front O2 heater circuit. From what I have read on this thread the exhaust is different. I have 2 O2 sensor connectors on the non vtec harness but only 1 O2 sensor in manifold (im still running the vtec exhaust) Rear one is downstream and goes through the dash harness. Friend wants to get the check engine light to go away so he can sell it. I'm just confused on what I need! Do I need exhaust manifold, cat, mid pipe? Do I need the non vtec dash harness or will the downstream O2 sensor not matter unplugged? Thanks for any help!!!

hondavtec2envy

hey guy were you able to find a fix for your cars?

I'm in almost the same situation and really need your help. I realize its an old thread sorry if I'm not posting in the correct area.


My motor blew on my

2005 Honda civic lx 4DR automatic and had my engine replaced with a 2003 Honda civic lx engine 4DR Automatic, now I have the p0135 (bank 1 sensor 1) engine code and cant pass nys inspection or register the car till I clear this code causing the check engine light.


So far ive tried replacing the upper oxygen sensor with a 2003 ngk oxygen sensor, the code came right back after starting the car, then I put in a 2005 denso wideband air fuel sensor code came right back after start up, ive changed the cat/exhaust manifold ($300) walker, I did a fresh oil change, new air filter, new spark plugs, fuel injector cleaner, crc G2P smog treatment, nothing is working... the car has the 2005 lx ecu, it also runs great the only problem is that 1 code/cel


what do you guys think the problem is, I'm stuck... Id appreciate any input

As far I know the engine harness in the car is the 2005 lx engine harness,

The ecu def is from the 2005 civic lx,
the upstream oxygen sensor is a 2005 wideband (denso) sensor I tested it with 2 different sensor so its not a faulty sensor.

Transmission 2005 Honda civic LX

The engine is the only thing from the 2003 Honda civic LX

Both engines are NON-vtech


when I hook up a code reader it gives the 1 code P0135 bank 1 sensor 1 but it doesn't look like the computer is getting any reading from the upstream oxygen sensor it doesn't show any readings or numbers its just N/A.

id appreciate any input

dabatman99

I think you are in the same boat as me. I think somebody changed my ECU. I have a 2005 civic LX and I think it might have a 2003 civic ecu. Changing mine over to the 2003 sensor is the right thing to do, but there is a wiring difference between the two model years. Check out this schematic from this link: 2002 honda civic dx: secondary oxygen sensor wire harness that..ecu

Civic_k20a

Hey targa
Sorry this a very old thread but I currently have this problem:..
Is that denso O2 same as OEM from factory?

Anyone figured it out?

The_iron_son

I know it's a little late but, have you thought about a possible ECU failure? When I worked at the dealership, I did see a couple ECUs set false codes. Other than that, I would check for battery voltage and ground at your connectors, check for proper pin fit at the o2 sensor connector, and proper resistance at the signal wire to rule out wiring/connection issues. I do know that what ever ecu you are running needs to match your exhaust set up (eg. 2004 dx ecu needs to use the 2004 dx catafold/o2 set up. Ex need to use the ex manifold, downpipe, o2 set up.) Engine year shouldn't matter because internals are the same, it's just the trim level and ecu year that matters. Again, I know this is 10 months later but hopefully it helps you or someone else with this same problem.

Side note: if you're doing a cat delete system, get a spark plug defouler and drill it out so your secondary o2 sensor fits and screw it in. This should trick your ecu in to thinking your test pipe is acting as a cat due to the difference of CO, NOx, and hydrocarbon readings between the primary and secondary o2 sensors. I'm running DC 4-2-1 headers with a test pipe and straight pipe and this is what worked for me.

Good luck!