First test [w/ DC sports headers (CA smog legal), intake (smog guy said it's ok) and an exhaust (only effects sounds but WILL effect smog if there's an exhaust leak which there isn't]

All three gases were off the boards EXCEEDING gross polluter limits.
NO: 2579@15mph & 1385@25mph
HC: 191@15mph & 106@25mph
CO: 1.56@15mph & .15@25mph

I installed a new Bosch o2 sensor and this was the next reading:
Smog guy only got readings at 15mph............
NOx: 3014
CO: .73
HC: 183

So the potential buyer and I got a new Impec? high flow cat (2/3 way) installed. And now for the results of this addition:
HC and CO dramatically dropped yet the NOx still didn't budge much. At 15mph 2297 was read along with 1741 @ 25mph.

I'm at a loss. I have no idea what to do. We've had the car run three times with two new parts added and I'm still left with "ultra high" nitrogen oxide readings. Can anyone please help me? TIA guys.

 

got a chipped ecu or adjustable fpr? If so use a stock ecu and set fuel pressure to stock psi. Do they test the car at idle? If so raise your idle to the maximum allowed idle speed. Also tune up the car.(new plugs, wires, cap, rotor, oil).

 

Isn't Nox reduced by having the car warmed up good before a test? Are your vacuum lines all connected and installed correctly? It's a retarded question I know, but sometimes it can happen.

 

NOx is from high combustion chamber temps (+2500 degrees), so anything that you can do to reduce that will help.

Try:
1) Checking your timing. Advanced timing will hurt you, set it to the retarded side of the spec. Not sure what exact car you have, since it looks like you have Accords, but Honda's usually have a +/-2 degree range. So if it is "X" degrees, set it to (X-2).

2) If your car has an EGR system, replace the EGR valve.

3) You can use a step colder sparkplug to remove some of the combustion chamber temp.

4) Higher octane gas will help cool things down too, but may affect(raise) the CO2/HC readings. Try this if those others values are already low and you have room to work with.

5) There's always "HEET" (the gasline antifreeze additive), basically isopropl (sp?) alcohol, or something similar that will burn clean.

 

Also, the header and intake are just going to make you run lean (provided you haven't done anything with a FPR or ECU, etc.). And that is going to mean hotter combustion temps. So you might want to try putting the stock parts back on if you have them (just for smogging).

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by XrcR6 &raquo;</TD></TR><TR><TD CLASS="quote">putting the stock parts back on if you have them (just for smogging).</TD></TR></TABLE>
I'll let the buyer know....we already found an OEM intake.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by XrcR6 &raquo;</TD></TR><TR><TD CLASS="quote">Try:
1) Checking your timing. Advanced timing will hurt you, set it to the retarded side of the spec. Not sure what exact car you have, since it looks like you have Accords, but Honda's usually have a +/-2 degree range. So if it is "X" degrees, set it to (X-2).</TD></TR></TABLE>
It's 18BTDC....some dude that the buyer knows was saying to put it at 16 or even 15....
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by XrcR6 &raquo;</TD></TR><TR><TD CLASS="quote">2) If your car has an EGR system, replace the EGR valve.</TD></TR></TABLE>
No EGR....
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by XrcR6 &raquo;</TD></TR><TR><TD CLASS="quote">3) You can use a step colder sparkplug to remove some of the combustion chamber temp.</TD></TR></TABLE>
I'll have to try this......
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by XrcR6 &raquo;</TD></TR><TR><TD CLASS="quote">4) Higher octane gas will help cool things down too, but may affect(raise) the CO2/HC readings. Try this if those others values are already low and you have room to work with.</TD></TR></TABLE>
But how high of an octane should I go? It's a stock motor w/ minor bolt ons...I don't think the compression is enough to run over 91
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by XrcR6 &raquo;</TD></TR><TR><TD CLASS="quote">5) There's always "HEET" (the gasline antifreeze additive), basically isopropl (sp?) alcohol, or something similar that will burn clean.</TD></TR></TABLE>
I was told by a few people that additives like that don't to squat..so I don't know who to believe....
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by CRX_1.8T &raquo;</TD></TR><TR><TD CLASS="quote">Isn't Nox reduced by having the car warmed up good before a test? Are your vacuum lines all connected and installed correctly? It's a retarded question I know, but sometimes it can happen.</TD></TR></TABLE>
Not sure, but we did break in the new cat already. I checked vacuum before I sold it and it ran at 22..uh...(sorry forgot the units)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by eda6 &raquo;</TD></TR><TR><TD CLASS="quote">got a chipped ecu or adjustable fpr? If so use a stock ecu and set fuel pressure to stock psi. Do they test the car at idle? If so raise your idle to the maximum allowed idle speed. Also tune up the car.(new plugs, wires, cap, rotor, oil).</TD></TR></TABLE>
Stock ECU and FPR. CA smog AFAIK don't run the tests at idle. 15mph (2nd gear) and 25mph (3rd gear) are done here....

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by MestizoRacer310 &raquo;</TD></TR><TR><TD CLASS="quote">
It's 18BTDC....some dude that the buyer knows was saying to put it at 16 or even 15....</TD></TR></TABLE>

That's sounds about right. For my car (CRX-SI w/D16A6) the spec is also 18 degrees BTDC +/-2. I set it to 16 BTDC last month when I smogged. If you have the stock hood, there should be a yellow sticker underneath and it has these specs. listed. The farther retarded you go will help to a certain extent, however they are supposed to verify that timing is in factory spec. In my case, I never saw them hit it with a timing gun or anything else. Yet the printout lists a value (which was wrong for me), so I think most the time the Tech will just accept the default/last value in those fields.


<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by MestizoRacer310 &raquo;</TD></TR><TR><TD CLASS="quote">
But how high of an octane should I go? It's a stock motor w/ minor bolt ons...I don't think the compression is enough to run over 91</TD></TR></TABLE>

Actually when I went to that inspection, I used 100 racing unleaded. I'm lucky to live by one of the few stations that has this at the pump in the Bay Area. It's overkill for my compression and octane doesn't directly affect power, but it will cool things down. Since it also affects the burn rate, it may affect CO/HC production. On my initial test I was only failing NOx @ 15mph, everything else was fine. Since I was way under average for CO/HC I thought I'd use it for the retest as safe measure. I did notice the CO/HC go up very slightly.


<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by MestizoRacer310 &raquo;</TD></TR><TR><TD CLASS="quote">
I was told by a few people that additives like that don't to squat..so I don't know who to believe....</TD></TR></TABLE>

I've seen the "Guaranteed to Pass" and "Clear Blue Sky" (or whatever they're called) and didn't trust them either. Supposedly they both have guarantees, but I was more concerned with what was actually in them, which I never did find out.

The HEET stuff is mainly for places back East/North, where you may experience freezing temps. Basically a water/moisture remover to prevent the gasoline from freezing. It contains methanol among other things. I've noticed aromatics like that burn clean anyway so it shouldn't add to the problem. (That's what they were trying to do with the oxygenated gasoline in CA with MTBE)


<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by MestizoRacer310 &raquo;</TD></TR><TR><TD CLASS="quote">
Not sure, but we did break in the new cat already.</TD></TR></TABLE>

Warming up the car is good for the catalytic converter. If its not hot it won't function properly. If the HC/CO values were good, it was warm enough.


I don't have my sheet near this terminal, but like I mentioned I basically passed everything the first time around, except 15mph NOx was like ~1200 vs ~800 max. 25 mph NOx passed, but was close, just under the ~800 max.

I went back for the retest and Passed. This was after doing timing, colder plug, ~5gallons of 100 octane and 2 bottles of HEET. NOx went to 3xx/6xx @ 15/25mph. I wish I could tell you what exactly did what, but I didn't want to go back multiple times after changing just one thing. I feel they all helped, to what extent is where its grey. Good luck.