failed HC at idle, repair time
#1
02-17-2011, 12:17 PM
failed HC at idle, repair time
hi all,
i need a bit of help on ideas to fix HC emission at idle.
honda civic 94 ex, 202,000 miles, stock engine. air cleaner clean, oil due for a change only slightly dirty. will change in the days following. female driver for 99% of its life, until i get ahold of it, then i shake the cob webs out of it by hitting WOT regularly.
heres the tested emissions specs
at 732RPM (at idle)
CO2 MEAS-15.00%
O2 0.00%
HC MAX-100 AVE-17 MEAS-170 (FAIL)
CO max-1.00 ave-0.00 MEAS-0.09
at 2492rpm
CO2 MEAS-14.90
O2 MEAS-0.00
HC MAX-130 AVE-12 MEAS-35
CO MAX-1.00 AVE-0.10 MEAS-0.20
car runs good, idle is smooth, doesnt seem to be any miss, very fast at stock. in the tank now is some lucas fuel cleaner (the one that claims to reduce NOX emissions) in 97 octane chevron currently. this cleaner was NOT in there during the test, its my attempt to clean the injectors incase they are dumping too much gas.
a bit of history
i smogged it 2 years ago, it didnt pass. so i changed the plugs, re-adjusted the valves for the first time, changed oil, put a new header on there and new O2 sensor (see below), possibly fuel filter (not sure on this one, i think i will do that now), changed air cleaner, possibly rotor. I have NOT replaced the timing belt yet.
It FAILED smog still, so i replaced CAT, and it PASSED.
SINCE THEN, the car maily sat in driveway for 2 years, i think we put about 5000 miles on it max, in last 2 years since last smog.
now its FAILING again.
THE PLUGS,
my first suspect is the plugs,
i looked at the plugs they are all clean, had a bit of ash deposits, or maybe sugar speckles, was light brown, and clean looking, i interpreted this as clean, but the rim on the plug was built up with carbon deposits. so i wonder if this is the indicator of runnign too rich, because these plugs have some sort of self-cleaning mechanism due to the type of metals used, and the air-gap technology so that might explain why the tips were clean, but the rim was carbon built up.
the factory gap, which i can FIND NO WHERE using google is about .023 thousandths on both ground electrodes. in the end i decided to stretch them to .030 thousandts despite the manufacturers recommendation that they dont need adjusting. the car ran better, but im not sure if that gap help clean off the idle HC's in the end or not. the next smog will tell.
could the plugs be the problem? should i get a hotter plug?
Plug wires
havent been changed at all to my knowledge, but we bought the car at just over 100k, so maybe before this they were... they look ok, and are seperated nicely, except in a couple spots they touch.
Rotor
not sure, ill open teh cap and inspect, but i think i filed the corrosion off the cap terminals last time, and prob cleaned up the rotor as well.
FUEL DELIVERY
im wondering if the stock fuel pressure regulator is adjustable, i thought of backing it off a tad to slow some fuel down at idle. would this help to pass smog? i DONT have a pressure guage, do they rent them at Auto Zone?
I do have a Mity-Vac that is good for gauging the vacuum, can i use this?
i was considering replacing the Injectors, i found them for $25 a piece refurbished. please try not to recommend me against the re-furbs unelss totally necessary, because im on a very tight budget right now. but should i be worrying about my injectors at all right now in the first place?
I need to change the fuel filter because im not sure if i did this last smog or not.
Exhaust
the one thing i replaced to performance was i put a Pace Setter header on there (was the cheapest i could find other than stock) and i put a new O2 sensor on there. i did this just before last smog 2 years ago.
One thing im concerned about on thsi one is the location of the O2 sensor, seems to be in an area of turbulence, rather than in a smooth flow area.
links to header images
http://www.jcwhitney.com/jcwhitney/s...49296_CL_1.jpg
http://www.jcwhitney.com/performance...stid=16663111#
so what is the first line of action here?
hotter plugs?
new injectors?
turn down the fuel pressure?
change the plug wires, cap rotor?
i need a bit of help on ideas to fix HC emission at idle.
honda civic 94 ex, 202,000 miles, stock engine. air cleaner clean, oil due for a change only slightly dirty. will change in the days following. female driver for 99% of its life, until i get ahold of it, then i shake the cob webs out of it by hitting WOT regularly.
heres the tested emissions specs
at 732RPM (at idle)
CO2 MEAS-15.00%
O2 0.00%
HC MAX-100 AVE-17 MEAS-170 (FAIL)
CO max-1.00 ave-0.00 MEAS-0.09
at 2492rpm
CO2 MEAS-14.90
O2 MEAS-0.00
HC MAX-130 AVE-12 MEAS-35
CO MAX-1.00 AVE-0.10 MEAS-0.20
car runs good, idle is smooth, doesnt seem to be any miss, very fast at stock. in the tank now is some lucas fuel cleaner (the one that claims to reduce NOX emissions) in 97 octane chevron currently. this cleaner was NOT in there during the test, its my attempt to clean the injectors incase they are dumping too much gas.
a bit of history
i smogged it 2 years ago, it didnt pass. so i changed the plugs, re-adjusted the valves for the first time, changed oil, put a new header on there and new O2 sensor (see below), possibly fuel filter (not sure on this one, i think i will do that now), changed air cleaner, possibly rotor. I have NOT replaced the timing belt yet.
It FAILED smog still, so i replaced CAT, and it PASSED.
SINCE THEN, the car maily sat in driveway for 2 years, i think we put about 5000 miles on it max, in last 2 years since last smog.
now its FAILING again.
THE PLUGS,
my first suspect is the plugs,
i looked at the plugs they are all clean, had a bit of ash deposits, or maybe sugar speckles, was light brown, and clean looking, i interpreted this as clean, but the rim on the plug was built up with carbon deposits. so i wonder if this is the indicator of runnign too rich, because these plugs have some sort of self-cleaning mechanism due to the type of metals used, and the air-gap technology so that might explain why the tips were clean, but the rim was carbon built up.
the factory gap, which i can FIND NO WHERE using google is about .023 thousandths on both ground electrodes. in the end i decided to stretch them to .030 thousandts despite the manufacturers recommendation that they dont need adjusting. the car ran better, but im not sure if that gap help clean off the idle HC's in the end or not. the next smog will tell.
could the plugs be the problem? should i get a hotter plug?
Plug wires
havent been changed at all to my knowledge, but we bought the car at just over 100k, so maybe before this they were... they look ok, and are seperated nicely, except in a couple spots they touch.
Rotor
not sure, ill open teh cap and inspect, but i think i filed the corrosion off the cap terminals last time, and prob cleaned up the rotor as well.
FUEL DELIVERY
im wondering if the stock fuel pressure regulator is adjustable, i thought of backing it off a tad to slow some fuel down at idle. would this help to pass smog? i DONT have a pressure guage, do they rent them at Auto Zone?
I do have a Mity-Vac that is good for gauging the vacuum, can i use this?
i was considering replacing the Injectors, i found them for $25 a piece refurbished. please try not to recommend me against the re-furbs unelss totally necessary, because im on a very tight budget right now. but should i be worrying about my injectors at all right now in the first place?
I need to change the fuel filter because im not sure if i did this last smog or not.
Exhaust
the one thing i replaced to performance was i put a Pace Setter header on there (was the cheapest i could find other than stock) and i put a new O2 sensor on there. i did this just before last smog 2 years ago.
One thing im concerned about on thsi one is the location of the O2 sensor, seems to be in an area of turbulence, rather than in a smooth flow area.
links to header images
http://www.jcwhitney.com/jcwhitney/s...49296_CL_1.jpg
http://www.jcwhitney.com/performance...stid=16663111#
so what is the first line of action here?
hotter plugs?
new injectors?
turn down the fuel pressure?
change the plug wires, cap rotor?
Last edited by wolfdogg; 02-17-2011 at 12:32 PM.
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