fakesmi1e

hello i swapped my 98 civic from auto to manual and it began having idle issues , i noticed it had a mil on cluster so i pursued it first and in the midst of cleaning the car i just bought i found a paper saying the vehicle had a low egr flow code , so i cleaned the egr valley a good bit then i put everything back together and it smoothed out the idle a fair bit but i reviewed the guides on swapping the transmissions over again and it said i had to swap the intake manifold and the throttle body and the idle air control valve , could that be the cause of the check engine light , i really look forward to any replys and i will be double checking everything back again with more info in two days when i fly back home and i shall post any updates

tony_2018

show me this guide

mk378

The auto EX has a different idle air control valve than manual EX, which requires changing the intake and re-wiring when you put in a manual ECU. Not sure about the HX.

fakesmi1e

https://honda-tech.com/forums/honda-civic-del-sol-1992-2000-1/%5Bfaq%5D-96-00-auto-manual-swap-full-detail-44pics-1337459/

HondaPartsHero

Civic HX - CVT to Manual Transmission Swap

DIY: HX CVT-to-Manual Tranny Bracket & Mount | ClubCivic.com - Your Online Civic Community

fakesmi1e

Sorry i took so long i was having issues with my log in . I found a code for a dead engine coolant temp sensor which i can fix easily . The only troubling part is the other code i found its p1655 unused power b . Do i just need a different transmission ecu or should i jump wires together or hook up a resistor ?

eghatch9295

iTrader: (1)

you should be using the manual ecu, including the 5 wire o2

chrysler kid

The good write up on the cvt to manual swap was pretty detailed.

Basically you need to extensively convert the old engine harness to accept the manual sensors so you can run a manual transmission hx ecu.

The IACV on cvt is different
The egr system on a cvt car is extremely different

The egr system on a manual car has no vacuum lines. It is all controlled electronically.

So you can run it as a manual on the cvt ecu but your speedometer is going to be off, and you're going to get a bunch of transmission fault codes, and the car isn't going to run very well

fakesmi1e

not to sure on what that implies but in short your saying i need an entire harness to plug into my manual ecu because the auto harness will not work?

tony_2018

Read it again....carefully.

fakesmi1e

Welp i replaced the ecu with one from a manual dx and the car runs alot smoother , and its throwing codes for both o2 sensors , does anyone know any kits for the five pin o2 sensors and should i replace both ?

tony_2018

What in the hell...you couldn't just swap in a 2 wire iacv and continue using the hx ecu?

mk378

As long as you're keeping the VTEC-E engine, you should strive to build the car out into a true manual HX. HX engine with DX controls is not going to work well.

fakesmi1e

It wasnt throwing codes for the iacv it was throwing transmission codes , and its running fine i just have o2 sensor codes because its not looking for the cvt transmission , ive been looking for the parts for the "true manual hx" but im not finding anything so my buddy and i swapped the ecus and it isnt looking for the sensors on the auto tranny i think its just looking for a different type of o2 sensor like heated or non heated , although this is becoming a bit more discouraging each time i try something sorta like what happend to the guy in swap guide

mk378

A DX ECU won't even activate VTEC. This means the VTEC-E engine will be ******* along in its 12 valve mode through all rpm.

It's actually rather simple. You cannot get a properly running HX engine without the full complement of special HX parts supporting it. People who try to piece something together with DX/EX stuff are going to have a Bad Time. This also gives you the lean burn 4 or 5 more highway mpg that the HX was designed around.

chrysler kid

From my loose memory, you have to weld in a new transmission mount on the passengers side because the cvt transmission has a very different mount.

The speed sensors for the cvt is different.

The cvt engine harness has extra plugs for the egr system. It has an egr solenoid, and an egr vacuum control solenoid on the firewall. Each have separate plugs, and function differently

The hx manual engine harness has a different oxygen sensor pinout. The manual cars including California models use a 5 wire wide band sensor, cvt has 4 wire sensor

The hx d16y5 engine operates in 12 valve mode until vtec is engaged and it operates in full 16 valve mode. Your dx ecu isn't able to comprehend the lower temperature readings from the oxygen sensors, and it can not raise those temperatures by using the egr system because the egr is not used on any other civic model.

So to re state my previous comment, you need to convert the engine harness to an hx manual harness and run an hx manual ecu. The d16y5 can not function without the y5 ecu because the car runs on only 12 valves and not 16 valves like ever other d16 engine.

So yes you need to convert the car to run on the hx manual ecu. The y5 is a lower compression motor and uses the egr valve to meet emissions and fuel system performance metrics

In conclusion there is a specific reason why I can and have found so many used un molested civic hx 6th gens, they do not take well to being modified, and it's easier to do an engine swap that it is to do any performance mods to the y5 engine because of its unique layout to get maximum gas mileage

To answer the next question, would it be easier to just put a y7 head on the y5 block. No, the y5 has dished pistons and runs a lower compression ratio. So you could run a low compression y7 hybrid and it would feel down on power and sluggish. But at this point it's almost easier to just swap the engine

tony_2018

Thats not what I'm talking about.

fakesmi1e

Thank you crystler kid you told me what i need to know , gonna do the y7 engine swap , seems like the only way im gonna come out on top of this mess

tony_2018

:facepalm:

It cannot be that hard to find an hx 5spd...

chrysler kid

Well to answer your question, no you could not swap in a 2 wire iacv onto the y5 and run the cvt ecu. I mean you could, but if you live in an area with vehicle inspections you would never have it road legal

He doesn't want a manual hx specifically. He wants a manual transmission 6th gen coupe.

I concur that it would be easier to sell it and buy another car, but in the honda world a clean chassis is a clean chassis

Heres the full write up on the manual swap
Civic HX - CVT to Manual Transmission Swap

Basically the author never fully got it running right. He was onto changing the oxygen sensor wiring to run a manual ecu, but he needed to swap the entire intake manifold to get that far. And a y5 intake manifold can run $300+ for one with the sensors if you can find one. A y5 manual ecu can run $200 or so, and a wideband o2 sensor another $140

Then you still have to figure out how to wire a vehicle speed sensor into the harness to the ecu since the cvt has its own separate ecu

So by the time you find a manual transmission hx ecu, a manual trans hx intake manifold, and wire the original harness you're already *** over elbows in basically **** work to get a hacked y5 running right. For the price and work it would be easier to source a wrecked d16y7 or y8 with an ecu and harness... convert an hx to an ex or lx

So the oxygen sensor codes are normal if you're on a dx ecu. The oxygen sensor is just expecting a hotter burn reading from the exhaust but because it's a y5 head on 12 valves, the dx ecu is putting in too much fuel and causing lower exhaust temps than what the dx ecu sees as acceptable

fakesmi1e

Yeah it should be about 7 or 8 hundred bucks and ill finally be able to get out of this note , thanks again chrystler kid you saved me alot of money and busted knuckles