wolfhalen

Hello Honda Tech

My civic has always run pig rich since i got it

The previous owner had installed a header and straight exhaust. When i finally started trying to get the car running right i noticed the 5 wire plug for the o2 sensor just hanging there with nothing plugged in!!!!

The fault code originally was p1167 02 heater failure

The secondary sensor was already installed in the back of the header

So i bought the (very expensive) wideband sensor and welded a bung on to install it.

Well the car ran much better for a while but seemed to learn itself back to the extremely rich state.


now it reads p1169 primary ho2s high input - online i found this means rich condition well duh

additionally i get a p0117 coolant temp circuit low input - replaced the coolant sensor, no change

anyway i would appreciate any suggestions on getting this thing dialed back to acceptable fuel consumption thanks

Former User

Check the O2 sensor and ECT sensor wires.

Which ECT sensor did you replace? Post pictures.

Has the engine been swapped or is there a D16Y5 under the hood?

wolfhalen

Thanks for the reply!

Ok i will check the wires in the daylight

i replaced the sensor at the front of the head where the upper radiator hose is located

and yes there is the original d16y5

Former User

If you want the engine to run as intended (lean), you must fix the O2 sensor and ECT codes. Did you reset the ECU to verify that both codes repeat?

You should also clean the EGR valve and the EGR chamber in the intake manifold. Both are probably heavily clogged with carbon.

grumblemarc

iTrader: (4)

So no catalytic converter? I'm thinking you need to revert to the original hardware.

wolfhalen

Yeah no cat

i cant find anything wrong with wiring as yet although i didn't tear into it to far because i have to go to work

im wondering unless i got a bad o2 sensor brand new (its an ngk) if maybe my ecu is shot

wolfhalen

i have had no luck finding another fault

an educated guess if the ecu is bad? is there a procedure to determine for sure?

Former User

Are you testing the wires with a multimeter?

wolfhalen

yeah and its a pita

i cant believe even in open loop it should be this rich my bumper is covered in black soot

compression is 180 across the board

Former User

Details? Do you know how to do the electrical tests indicated in the diagram?

How did you test the ECT wires and ECT sensor?

wolfhalen

i know how to do them its just a royal pain to do the second test between the ecu plug and o2 sensor plug
(edit: i had to unwrap the harness and move the wires and plug to reach where the o2 sensor is now installed.)

i will give it another shot tho (i work an extreme amount of hours)

in your opinion could it run rich enough to foul plugs with a bad primary sensor?

Former User

The combination of the two codes is causing the engine to run very rich. You want to minimize driving the car until you fix both codes.

wolfhalen

ok i will do my best for the second part of that electrical test

i really cant wait to buy another wideband sensor

thank you for the help

wolfhalen

ok i dug into it and found that my green/black wire for sensor ground had popped out of the o2 sensor connector. thought i was in the clear with that !

moved on and found the temp sensor and vtec pressure switch plugs were swapped yikes

ok hooked neg bat cable up again and fired her up ran much better

p0117 code gone
1 minute later p1169 returns

so i go through the tests you gave me and the wires check out both the 5v on the white wire and continuity to the 16p connector for the sensor ground

yay im left to buy another f'n wideband

i bought the brand new ngk sensor which i would have expected to be good
so im wondering if having the sensor ground unplugged coulda fried it, seems possible

wolfhalen

I would like to post an update - to help any who might search

So due to previous help here and a bit of luck i found the NTK o2 sensor i bought was junk!

To anyone with an primary o2 sensor problem on a manual HX you need to buy the Denso 2345052 -wouldnt use Bosch or NTK only the denso

Anyway, someone swapped various parts on this car including the intake with a non EGR one, and i come to find out, the injectors !!

I noticed when i plugged my scanner in that my fuel trims were reading -35% at idle WHOA! after some research found that 240cc injectors were installed on the damn thing
Ok so i replaced those with the proper ones and its running almost perfect now

However my fuel trims go more positive now like up to 14% while cruising
so im gonna check for vacuum leaks

Changed the intake for a d16y8 one with an egr valve, egr code comes on after a while though. wonder if the ports on the head could be clogged? cuz the manifold isn't

tony_2018

There is no d16y8 with an egr port.

chrysler kid

So you converted your rare lean burn vtec motor into a plain old run of the mill ratted out rice mobile with 115hp of bumble bee fury?

That extended 02 sensor for the header is not going to be giving the ecu the accurate readings. Put a stock exhaust manifold and cat back on that car immediately


So you took off the y5 intake manifold? Why

wolfhalen

did you read my post chrysler kid? The car came with various parts swapped out i didnt rice out anything.

Where in my post does it say that I tried to hot rod this car?

Im still getting wild fuel trim readings with the proper injectors installed .. i suspect im on my own with that

I could install a cat on the car, im not going to spend the money for a complete oem system

I dont believe that would solve my fuel trim issue since it corrects from the primary sensor

chrysler kid

Moving the primary 02 sensor further down stream with the aftermarket header compromises the sensors readings.

You have a header on the car and you're missing a Catalytic converter, or its been moved further down stream.

Y5 manifolds are the only ones with egr valves

Gator417

Not everybody has the passion for the Y5/HX as you do CK. I opted for the Y5 because I desperately needed an engine and that was available. I opted for a Y8 intake and exhaust manifolds because I didn't want to run 2 cats on my car or mess with EGR. I opted for a P28 ECU because that's what I had that would work. I opted for a Z6 throttle body because that's what's needed for a P28 to run a Y8/Y5. Now it runs pretty good and has a better power band than the Y8 & Z6 I had in it before. When I figure out how to get the VTEC-E to kick in, I'll be set. Just because something is rare doesn't make it valuable or collectible or even worth rescuing.
Good luck and please keep us informed on your progress.
Gator

tony_2018

wth....2 cats? On which civic do you know of that runs 2 cat converters?

Gator417

None, and I don't want to be the first.
The stock Y5 exhaust manifold has a cat built in to it. My car already has a cat in the stock location (for an LX). Using a Y5 manifold would have given me 2 cats. That's also why I didn't run the stock ECU (P2N). I would have had to extend my O2 sensor wiring, and figure out the EGR plumbing as well. Not to mention, the car from which it came had the CVT & I wasn't sure how the ECU would like me doing the gear selecting. I was in a big hurry to get all of this done, so I went with a simpler route. I'm very happy with the results and I'll post some details as soon as I get the final tuning (TPS, ignition timing & idle reset) complete.
Gator

eghatch9295

iTrader: (1)

the y5 can be an interesting motor to play with, but you do need some tuning done. roller rockers aside, the head is still very much an oddball. id almost feel better running it on a p06 until you're able to play with some basemaps.

tony_2018

Than you obviously don't know what you're typing, using a y5 manifold does not mean you run 2 cats.

edit: fyi the d15b 3 stage vtec had regular headers with the o2 sensor near the lower part of the radiator, cat converter was separate.

Gator417

"Than (sic) you obviously don't know what you're typing, using a y5 manifold does not mean you run 2 cats.

edit: fyi the d15b 3 stage vtec had regular headers with the o2 sensor near the lower part of the radiator, cat converter was separate." tony_2018

Yes Tony, I do know what I'm typing, you just don't understand what you're reading.
I didn't say anything about a D15B or 3 stage VTEC. Its a totally different setup as the Y5.

FYI, the Y5 had a cat integrated into the exhaust manifold. Its one piece, doesn't unbolt or come apart. My car already has a cat on the tailpipe, so if I were to run BOTH the stock cat AND the integral cat on the Y5 manifold, that would make 2 cats. Get it?

"the y5 can be an interesting motor to play with, but you do need some tuning done. roller rockers aside, the head is still very much an oddball. id almost feel better running it on a p06 until you're able to play with some basemaps." eghatch9295

The Y5 head is the same casting as the Y8, same valves & everything. The valvetrain is quite unique though, as is the way in which it functions. Perhaps it would be more fun to play with if it weren't my DD and only transportation besides my LPCs. I haven't a clue how to change basemaps or any of what goes on inside the ECU & I don't have a P06 lieing around. It runs great on a a stock, virgin, unmolested P28 though, so there's really no point.

Wolfhalen,
Sorry if we've hyjacked the thread. I don't know much about this bastard Y5, but I'm happy to share what I've learned. Good luck.
Gator