Failed Smog Across the Board - Interpretation
12-19-2008, 11:57 PM
#1
Elite Member
Thread Starter
iTrader: (6)
Join Date: Sep 2007
Location: CA
Posts: 2,016
Total Cats: 13
Failed Smog Across the Board - Interpretation
Warning - Hand holding needed...
My brother just failed across the board on a busted *** 95 Probe V6. This stuff is Egyptian to me, so can someone please give me their interpretation and solution for passing this CA smog test.
Thanks.
My brother just failed across the board on a busted *** 95 Probe V6. This stuff is Egyptian to me, so can someone please give me their interpretation and solution for passing this CA smog test.
Thanks.
Reply
0
0
12-20-2008, 12:03 PM
#3
Boost Pope
iTrader: (8)
Join Date: Sep 2005
Location: Chicago. (The less-murder part.)
Posts: 33,026
Total Cats: 6,592
Without actually contributing any useful information, let me just say that this is one of the more impressive failure I've seen. He managed to exceed the limit by a considerable amount in all three rated categories, and by a factor of 2x to 3x in both HC and NO! I am truly humbled by his sociopathic disregard for life on this planet. 
Seriously, though. The numbers are somewhat confusing. HC (hydrocarbons) is unburnt fuel and is generally symbolic of an overly rich mixture. NO (oxides of nitrogen) are typically by-products of excessively high temperature or pressure in the chamber during the combustion event, and are usually indicative of an overly lean mixture. So a simplistic interpretation here is that your brother's car is both too rich and too lean at the exact same time.
Ok, so what can be done here...
High NO is often caused by a malfunctioning EGR system. So clean and inspect that.
I'm thinking that the high HC might be a by-product of some funky injectors. If he's got one injector that's flowing considerably more (or less) than the others, then the engine will over-compensate the "good" injectors to achieve an acceptable average AFR, and thus the engine will be both rich and lean.
I would recommend that he put some time and elbow grease into the EGR system, and some money into a new cat and O2 sensor(s)- it goes without saying that these are automatically suspect on an OBD-I vehicle of this age.
If the car still blows bad numbers, then the injectors might benefit from a visit to the Sexy Nurse Clinic.
Seriously, though. The numbers are somewhat confusing. HC (hydrocarbons) is unburnt fuel and is generally symbolic of an overly rich mixture. NO (oxides of nitrogen) are typically by-products of excessively high temperature or pressure in the chamber during the combustion event, and are usually indicative of an overly lean mixture. So a simplistic interpretation here is that your brother's car is both too rich and too lean at the exact same time.
Ok, so what can be done here...
High NO is often caused by a malfunctioning EGR system. So clean and inspect that.
I'm thinking that the high HC might be a by-product of some funky injectors. If he's got one injector that's flowing considerably more (or less) than the others, then the engine will over-compensate the "good" injectors to achieve an acceptable average AFR, and thus the engine will be both rich and lean.
I would recommend that he put some time and elbow grease into the EGR system, and some money into a new cat and O2 sensor(s)- it goes without saying that these are automatically suspect on an OBD-I vehicle of this age.
If the car still blows bad numbers, then the injectors might benefit from a visit to the Sexy Nurse Clinic.
Reply
0
0
12-20-2008, 12:05 PM
#4
Without actually contributing any useful information, let me just say that this is one of the more impressive failure I've seen. He managed to exceed the limit by a considerable amount in all three rated categories, and by a factor of 2x to 3x in both HC and NO! I am truly humbled by his sociopathic disregard for life on this planet.
Seriously, though. The numbers are somewhat confusing. HC (hydrocarbons) is unburnt fuel and is generally symbolic of an overly rich mixture. NO (oxides of nitrogen) are typically by-products of excessively high temperature or pressure in the chamber during the combustion event, and are usually indicative of an overly lean mixture. So a simplistic interpretation here is that your brother's car is both too rich and too lean at the exact same time.
Ok, so what can be done here...
High NO is often caused by a malfunctioning EGR system. So clean and inspect that.
I'm thinking that the high HC might be a by-product of some funky injectors. If he's got one injector that's flowing considerably more (or less) than the others, then the engine will over-compensate the "good" injectors to achieve an acceptable average AFR, and thus the engine will be both rich and lean.
I would recommend that he put some time and elbow grease into the EGR system, and some money into a new cat and O2 sensor(s)- it goes without saying that these are automatically suspect on an OBD-I vehicle of this age.
If the car still blows bad numbers, then the injectors might benefit from a visit to the Sexy Nurse Clinic.
Seriously, though. The numbers are somewhat confusing. HC (hydrocarbons) is unburnt fuel and is generally symbolic of an overly rich mixture. NO (oxides of nitrogen) are typically by-products of excessively high temperature or pressure in the chamber during the combustion event, and are usually indicative of an overly lean mixture. So a simplistic interpretation here is that your brother's car is both too rich and too lean at the exact same time.
Ok, so what can be done here...
High NO is often caused by a malfunctioning EGR system. So clean and inspect that.
I'm thinking that the high HC might be a by-product of some funky injectors. If he's got one injector that's flowing considerably more (or less) than the others, then the engine will over-compensate the "good" injectors to achieve an acceptable average AFR, and thus the engine will be both rich and lean.
I would recommend that he put some time and elbow grease into the EGR system, and some money into a new cat and O2 sensor(s)- it goes without saying that these are automatically suspect on an OBD-I vehicle of this age.
If the car still blows bad numbers, then the injectors might benefit from a visit to the Sexy Nurse Clinic.
Yeah. What he said!
Reply
0
0
12-20-2008, 03:06 PM
#5
2 Props,3 Dildos,& 1 Cat
iTrader: (8)
Join Date: Jun 2005
Location: Fake Virginia
Posts: 19,338
Total Cats: 573
joe, couldn't you have a clogged injector and an ECU that reads that as "lean--inject more fuel" until it's rich in some and lean in others?
also google.
Emissions Testing
also google.
Emissions Testing
Reply
0
0
12-20-2008, 05:25 PM
#6
Boost Pope
iTrader: (8)
Join Date: Sep 2005
Location: Chicago. (The less-murder part.)
Posts: 33,026
Total Cats: 6,592
Originally Posted by Joe Perez
I'm thinking that the high HC might be a by-product of some funky injectors. If he's got one injector that's flowing considerably more (or less) than the others, then the engine will over-compensate the "good" injectors to achieve an acceptable average AFR, and thus the engine will be both rich and lean.
Reply
0
0
12-20-2008, 07:15 PM
#8
Kenzo, without knowing the state of tune of the vehicle the list of culprits could span a small book.
I would ask:
How many miles on said vehicle?
Is it a v-6 or 4cyl?
When was the last time a complete tune-up including spark plugs and wires and distributor cap and rotor (I think the Probe has one) air cleaner etc. was performed?
Does the engine run smooth or rough (misfire)?
The readings above suggest a vehicle that might be experiencing lean misfires which would cause high combustion temperatures leading to those very high levels of NO (oxides of nitrogen) combined with the high CO and HC (essentially raw fuel).
Tracing gas emissions problems is difficult at times and specially with high mileage vehicles (which this seems to be the case here). I suggest checking the basics but you might have to end up taking it to a pro at the end. After all they will have the 5 gas analyzer to verify any repairs.
Tony
I would ask:
How many miles on said vehicle?
Is it a v-6 or 4cyl?
When was the last time a complete tune-up including spark plugs and wires and distributor cap and rotor (I think the Probe has one) air cleaner etc. was performed?
Does the engine run smooth or rough (misfire)?
The readings above suggest a vehicle that might be experiencing lean misfires which would cause high combustion temperatures leading to those very high levels of NO (oxides of nitrogen) combined with the high CO and HC (essentially raw fuel).
Tracing gas emissions problems is difficult at times and specially with high mileage vehicles (which this seems to be the case here). I suggest checking the basics but you might have to end up taking it to a pro at the end. After all they will have the 5 gas analyzer to verify any repairs.
Tony
Reply
0
0
12-20-2008, 07:42 PM
#9
Boost Pope
iTrader: (8)
Join Date: Sep 2005
Location: Chicago. (The less-murder part.)
Posts: 33,026
Total Cats: 6,592
Good point. If it does have a distributor, then a new cap & rotor should be on the list as well. Might as well do the plugs & wires while you're in there too- they're cheap.
Reply
0
0
12-21-2008, 10:13 PM
#10
Elite Member
Join Date: Jul 2005
Posts: 6,420
Total Cats: 84
High HC = misfire.
The fact that the O2 doesn't go to zero despite the excess means the cat is weak. The cat should be consuming all the O2 in order to oxidize the CO and HC. Don't replace the cat until the other problems are fixed - else the new cat will suffer.
The fact that NOx is high suggests a lean condition - the misfire could be a lean misfire.
Things to check:
bad O2 sensor - check if it's cycling
if not, check for bad temp sensors or a bad AFM
The fact that the O2 doesn't go to zero despite the excess means the cat is weak. The cat should be consuming all the O2 in order to oxidize the CO and HC. Don't replace the cat until the other problems are fixed - else the new cat will suffer.
The fact that NOx is high suggests a lean condition - the misfire could be a lean misfire.
Things to check:
bad O2 sensor - check if it's cycling
if not, check for bad temp sensors or a bad AFM
Reply
0
0
Thread
Thread Starter
Forum
Replies
Last Post
Zaphod
MEGAsquirt
47
10-26-2018 11:00 PM
