SlammedAccord96

Ok, I have an OBD1 JDM H22A (JDM p13 ECU) in my 91 accord lx 5spd sedan, only mod is an aftermarket header. Had a FULL tuneup 500 miles ago (fuel/air/oil filter, pcv valve, plugs/wires/cap/rotor/ignitor/coil, thermostat). Runs good, I use 91 octane gas. Only codes thrown are 17 (vehicle speed sensor (sensor bad) and 22 (V-TEC pressure solenoid - the vtec wires aren't hooked up at all, I need ECU pins)

Anyway, the cam timing was off by one tooth on the intake side, so it was running like ****, but I drove it for about 500 miles. Plugs were all black, so I ran seafoam (the whole bottle through the intake), and changed the plugs.

But, I'm wondering if I fouled my O2 sensor and OEM-type replacement cat (I replaced them both 500 miles ago when I put the engine in). I took the car to get inspected, and here's my results:

Hydrocarbons (PPM), limit 220PPM:
Idle - 196 ppm (PASS), 2500RPM - 211ppm (PASS)

Carbon Monoxide (CO) (%), limit 1.20%:
Idle - 2.61% (FAIL), 2500RPM - 7.85 (FAIL)

CO(%) + CO2(%):
Idle - 13.82%, 2500RPM 17.4%

So, do you guys think my cat and O2 sensor are to blame? Here were my results from before I fixed the cam timing:

Hydrocarbons (PPM), Limit 220PPM:
Idle - 2936ppm (FAIL), 2500rpm - 7323ppm (FAIL)

Carbon Monoxide (%), Limit 1.20%:
Idle-4.48% (FAIL), 2500rpm - 8.62%(FAIL)

CO(%)+CO2(%):
Idle-10.12%, 2500rpm - 16.12%

Would these numbers kill the catalytic converter and O2 sensor like they did to my spark plugs? I have two weeks to fix it before my temp tag runs out, so should I buy a new O2 sensor and cat? I'm not sure what else to try really...thanks! BTW they don't test NOX here...

hondaccord

i could see the o2 being fouled... the cat possible, but not as likely. If you want the cheep fix then use a spark plug anti fouler on the o2. first check the voltage on your o2.

Turbowa

More then likely you will need a new cat. those numbers are pretty high. I would also check ign. timing.

hondaccord

also disregard my statement you should replace both the o2 and cat. that trick is to run cat-less on an obd2 car, without throwing a cell.

SlammedAccord96

Ok, I'll check the ignition timing, but would those high numbers (7.85% when it should be 1.20%) only be caused by the cat? Is the cat that important? Thanks for the quick responses guys!

zombiesid1

Hydrocarbons (PPM), limit 220PPM:
Idle - 196 ppm (PASS), 2500RPM - 211ppm (PASS)

Carbon Monoxide (CO) (%), limit 1.20%:
Idle - 2.61% (FAIL), 2500RPM - 7.85 (FAIL)

CO(%) + CO2(%):
Idle - 13.82%, 2500RPM 17.4%

So, do you guys think my cat and O2 sensor are to blame? Here were my results from before I fixed the cam timing:

Hydrocarbons (PPM), Limit 220PPM:
Idle - 2936ppm (FAIL), 2500rpm - 7323ppm (FAIL)

Carbon Monoxide (%), Limit 1.20%:
Idle-4.48% (FAIL), 2500rpm - 8.62%(FAIL)

CO(%)+CO2(%):
Idle-10.12%, 2500rpm - 16.12%

holy crap! 7kppm on HC? That is quite the lean miss. High CO readings are caused by partially burned fuel. Namely, too rich. High HC is caused by unburned fuel as in never burned, normally the mixture is too lean to cause that.

The required numbers, if you're close, signify a gross polluter. The fact that your HC is close to the limit and CO is well over, I'd bet you have something causing a rich fuel mixture. Maybe a vacuum leak too? Sometimes fuel pressure regulator diaphragms rupture and leak fuel into the signal line or your O2 could be pushing your ECU to make it rich. Do you have access to a multimeter? It'd be cool if you could tell us your fuel trim and O2 voltage readings. Make sure to measure O2 voltage when the thermostat opens on the engine.

3zFree

This is not a vacuum related problem, if it was his readings would get better with RPM as engine vacuum became less. This is an electrical problem, OP if you're using any aftermarket components in the primary/secondary (most likely plug wire[s]) I suggest going out and buying OEM parts.

@zombie, I've never seen so much false/misleading information in one post.


Modified by 3zFree at 2:45 AM 4/25/2008

SlammedAccord96

I have Neuspeed wires that are like a month old, and I used some b/s autolite plugs because they were out of the v-powers. I did notice that I had my intake air temperature sensor unhooked, so I hooked it back up but the car runs the same, so I don't know how important the sensor is. Everything in my fuel system is stock (injectors are stock JDM H22A, FPR, pump, ECU, etc.). But I do believe that the O2 sensor is fouled because of the high emissions I was driving with for 500-1000 miles. I am going to replace the O2 sensor and cat and retest and I'll let you guys know, thanks for all the help!

zombiesid1

sorry, I guess I didn't really think out my post. You're right the vacuum leak would cause HC to be worse under idle but less so under cruise. Besides that though, it's conventional drivability diagnosis to look for a something causing a rich mixture for CO and lean mixture/misfire for HC. The fact his HC are marginal I suppose could be attributed to the rich mixture stressing his secondary ignition to the point of misfire. Maybe your suggestion for plug wires may help, but how would that correct his overrich fuel mixture?

3zFree

Easy for example one crappy wire with too much resistance, spark in 1 cylinder only is not strong enough for complete combustion. Whats coming out of that cylinder? Partially burned fuel/HC's. Doesn't necessarily mean the car is running rich, just a byproduct of incomplete combustion. As you said before the HC's are marginal, which makes me think its not a problem with anything that might effect all cylinders, thats why I say spark plug wire[s].


OP: Get rid of those wires/plugs, buy OEM ones.

hondaccord

well a bad map could cause this too. I almost wonder the condition of the coil.
just wanted to add that doesn't the jdm ecm not have the same emission controls?

3zFree

Wouldnt the coil mess with all cylinders causing a more severe problem?

zombiesid1

A bad cap could cause it too I guess. When I changed out the cap on my F22 there was all sorts of corrosion on the wire contacts and the rotor. But 7% CO? Maybe like 4 or 5%. I'm not sure the laws on your state but in WA if you spend $150 on repairs you can waive your emissions test. I always reccomend before you start guessing and throwing parts at a emissions problem, go to an authorized emissions repair facility, do their half-assed spark plugs-wires-dist cap and rotor to get the waiver and then try to fix it unless you're sure you can do it for less. I'm guessing since you're posting on the forum, you're trying to get this done cheaply and you're not sure what to do.

SlammedAccord96

thanks for the replies guys! First, sadly, Delaware's waiver is that I have to spend $750 at an authorized emissions repair facility. So that's not going to happen lol.

Cap/rotor/coil/ignitor/plugs/wires are all new - I had to put autolites in it though because they were out of my normal NGK V-powers (I plan to switch them soon). Wires are neuspeed and thicker then OEM, they're not the problem, I measured resistance and they're fine.

Does the JDM ecu have anything to do with it? I'm not really sure, I have all my emissions stuff hooked up. My friend told me to retard the ignition timing all the way when I get to the inspection place (it would cause it to run hotter and leaner, burn better, not good for performance but good for emissions).

My plan is this - replace plugs with NGK V-powers again, retard timing, and heat it up really good and go through (now I have the IAT hooked up, not sure if it matters). If I still fail, then I will replace the cat and O2 sensor. After that, if I'm still failing, well I haven't got there yet :D.

SlammedAccord96

Well - I finally passed!

Hydrocarbons

Were:
Idle-196ppm, 2500RPM-211ppm

Now:
Idle - 11ppm, 2500RPM-11ppm

CO:

Were:
Idle-2.61%, 2500RPM-7.85%

Now:
Idle - 0.00%, 2500RPM-0.17%

All I did was hook up the IAT sensor and retard ignition timing back very slightly...so to all reading this thread, remember every single sensor plays a part! And a cat won't do **** without a good running engine.

zombiesid1

Intake Air Temp sensor unhooked. That would make it rich but wouldn't set P0171. You didn't have check engine light on for IAT performance code?