Apexwagon

Hey everyone, this is my first post on this forum... so first things first.. HEY!!

I am a bit of a honda noob but have weekend-mechanical experience on quite a few other cars. I bought this civic with the CEL 2 weeks ago and agreed that I would be fixing it, but stupid me, did not research how much these wideband o2 sensors actually are... luckly I found an OEM brand new one for $100 on ebay.

So, needless to say, I have replaced the 5 wire wideband o2, reset the p07 ecu and followed the Honda Service manual's instructions on troubleshooting the still-appearing code. 3 times. (11-38 or so-11-49 in the manual).

yielded different results every time...

So I am coming to the forums, where I am HOPING somebody has had the same issue.. I have read numerous threads about this, spent hours reading up on them, trying to understand the service manual, amongst other things.

I NEED HELP!! I am pretty frustrated with the car and am honestly getting ready to cut my losses. I have until november to get this fixed because I start an intense medic school that will allow me no time due to studying and work. I bought this car to commute and just want it to work. I dont want to throw money and parts at it to guess and hope it will work..

I have heard the ECU can short internally, so maybe borrow someones to test and see if I need a new p07 ECU?? also read about cracked exhaust manifolds causing the o2 to read haywire readings, but I took off the heat shield and there appears to be no cracks..

also, when I go up hills or put any more-than-flat-ground-load on the engine and have my vents open, it stinks like there are exhaust fumes in the engine bay.. sorry for the long intro, but any help would be hugely appreciated!! its a fun car and want to keep it for a long time if i can get it to work properly with the knowledge of the honda community

-Mike

Former User

Did you cut, splice, solder, and heat shrink insulate the O2 sensor wires? Or was it plug and play?

Apexwagon

It was a plug and play, says Honda on it with the proper part number on it as well.

Former User

Check the Orn/Blu, Orn, Wht/Blu, and Wht for an open or short between the ECU (D14, D16, D8, and D3) and sensor.

Check for an open in the Grn/Wht wire between the O2 sensor and ECU D22.

Apexwagon

Will do wen I'm off work. I'll post with results.

Apexwagon

Orn/blu
3 in - none (open circuit)
5 in - none (open circuit)

orn (engine) - Blu/Grn (ECU connector)
none

wht/blu
none

wht (engine) - Blu/Yel (ECU)
none

grn/white
Does beep (short to ground)

With the tab of the D connector on bottom, looking at the female side of the connector, the grn/wht that beeps would be the top left, which I believe to be D22. The other grn/wht opposite that does not beep for an open circuit.

Apexwagon

a bump for advice on next steps..
Thanks!

Apexwagon

I also took a pic of the ECU bar code and pn below, it is:
37820-P07-L00
671-101224

Apexwagon

Looked deeper into my ECU, looks like I have a Cali model (P07-L00)but the Radiator Support beam has a "Manufactured in Canada" sticker or something along those lines of words. So, being the 92, it does come with the 5 wire and EGR, but this model is NOT supposed to go into Lean Burn mode.. so why am I getting a Lean Air Fuel Sensor CEL 48 if Lean Burn isnt even an option for this car/ECU combination?

Apexwagon

Also, on a cold start after sitting over night, it takes a few seconds of cranking for the engine to start. if I run it in the morning, then shut it down and let it completely cool down and fire it up later that day, it cranks over quick.

Former User

You need to explain your test results. What does none mean? Indicate what results you got from testing for a short (continuity to body ground) versus open (lack of end to end continuity) in each wire.

Apexwagon

The none indicates that the wire is open. And as I stated, the grn/wht has a short to ground.

Former User

Open is an electrical term meaning the wire is broken. If so, you have a bunch of broken wires.

Checking end-to-end continuity tests for a wire open. Checking for continuity to body ground tests for a wire short.

A ground wire is good if it has continuity to body ground, but the Grn/Wht ground wire should only have continuity to body ground with the key in ON(II).

Relic1

All USDM Civics were constructed in Canada (yes some were built in Japan, but generally speaking)
Cali-spec P07-L00 uses the same LAF that the 49-state version does, it simply does not enter lean-burn mode. (this is an ECU mode not O2 mode) Also you can get lean-burn if you pick up a 49-state P07. Indicated by Axx in the part number instead of Lxx.

your indication that there are exhaust fumes in the engine bay undear heavy load may point to a clogged cat or exhaust leak.
Exhaust leaks are pretty easy to find if you walk around the car with it running and listen to everything.
Clogged cat is a little more difficult but should be obvious when trying to rev closer to revlimit, it will sound like it's seriously straining to breathe. A clogged cat may also showup as an O2 sensor code... it certainly wouldn't appear to read correctly.

As far as connections to the O2:
O2 harness - ECU pin (harness)
yel/blk (orn) - A6 (orn/blk)
orn/blu (wht) - D14 (orn/blu)
orn (blu/grn) - D16 (blu/grn)
wht/blu(red) - D8 (wht/blu)
wht (NC) - D3 (blu/yel)
grn/wht(NC) - D22 (grn/wht)
blk (yel) - ground

make sure there is conection to the ECU pin from the O2 pin, and that only grn/wht and blk wires have connection to ground.

ECU pin locations for OBD1 --> http://b18c5eg.com/obd1.jpg

Apexwagon

Thank you for pointing out what wires are supposed to have a connect to ground, that eliminates my worry for the grn/wht. Good point on the clogged cat, could be clouding the manifold with gasses causing the o2 to go all out of its range. But the smell, it is like no smell I have smelt from any exhaust leak before, almost like cigarette ashes or something. I really want to find someone with some parts I could test on my car before throwing money at/into the car with no positive idea of an issue. The car is very quiet from outside and doesn't apparently sound like there are leaks.

Any suggestions on a next troubleshoot? I was going to spend some time and clean the egr to see if that helps..

Anyone in the San Francisco/bay area willing to hang out for a couple hours and test some parts on my vx? Lunch provided

Former User

Again, it's unclear what the results of your electrical troubleshooting were. See post #13.

roboaccord22

ok, have tried doing a fuel preasure test... check for broken, rusted leaking lines, make sure gas cap is on,, iv seen that throw that code before,, test fuel pump but, test the fuel presure first im not near a computer with alldata at the moment but you should be able to find the regular presure online.

Apexwagon

today, I replaced the spark plugs, wires and cap and rotor (previous owner said he just did this, but to my findings, it was blatently clear that nothing was touched). the car runs much smoother and turned right over on a cold start after sitting over night, also with no stench coming from the engine bay under load like before. I am in the process of resetting the ECU so updates to follow.

Later this afternoon I will also be checking timing and doing a compression test.. it has taken a while to locate a friends timing light/compression tester.

UPDATE FROM PREVIOUS POSTS:
There are no open wires or shorts to ground from the ECU. The only grounds are the grn/white and black like said in post 14.

and to everyone posting, thank you for your suggestions/tips, things wouldnt be as easy without the internet.

Apexwagon

the CEL didnt go away it consistently comes on 35 seconds after starting my car. and when it comes on, the RPM's drop a little and then come back to normal after a second or two.

Former User

Describe how you did the test for an open in the wires? Which wires did you test for an open?

Apexwagon

Went back and retested all wires in post #4. here are the results, ignition off/no key in ignition. I used a digital multimeter on the sound wave icon option.

-->orn/blue open to strut tower connector, beeping/saying Short from strut tower to connector that connects to the o2 sensor.

-->ORN which is blue/grn on main harness - has an open (no beep) between ecu and connectors near pass. strut tower, where it turns into orange. from orange at the strut tower to the plug that attaches to the o2, it has connection and beeps/says short on my digital multimeter.

-->Wht/Blu - Same as above two tests.

-->Wht in engine bay, Blu/yellow on ecu - Same result

-->Grn/Wht - Same result

Apexwagon

the sound wave option I used-


I have been testing off the connector on the right side, the medium sized one.

Apexwagon

Honda OEM o2


Connectors that test "short" from here to the o2 connector


o2 connector, how it came when I bought it.


Back of o2's connector

Apexwagon

bump

Former User

It's still unclear what your test results are in part because your terminology is confusing. Open means no continuity = broken wire = bad. Short means continuity to body ground = bad (for non-ground wire).

In addition, you need to mention what your multimeter probes are touching for every test result you mention.