had to get an emission test on my 05 mountain aire with the work horse chasis and the 8.1 engine. the tech. said the engine is running way to rich to which i have to agree as the exhaust smells like it is not burning all the fuel efficiently. there are no codes on the computer the air filter is new and the engine seems to run good. I would have expected to see a code if an O2 sensor was bad. Any thoughts as to what I should be looking at to solve this problem as I intend to work on it this weekend before it is retested on Monday, thank you for any suggestions.

How long since the spark plugs were changed? Ratio can still be ok, but it won't burn all the fuel causing high hydrocarbon emissions, if the plugs are worn out, wires are bad, or otherwise isn't getting strong spark. What about other maintenance? Is the air cleaner ok?

Hook up an OBDII reader and see what the air fuel ratio is. It should read 14.6-14.7 to be in the correct range, when the engine has warmed up. Those engines have a habit of burning the rear spark plug wires but that is usually noticed by a misfiring. The Tech should have been able to tell you what the problem was or at least an area of concern other than to just say the engine is running rich. In the USA most large auto parts stores will check your OBDII port to see if there are any codes.Are you burning an excessive amount of oil?

That engine in a motor home was known for eating up spark plug wires due to a lack of air flow across the wires and manifolds. I would make sure they're performing like they should. If they they're the OEM wires, I would replace with a good quality high temp set, along with new spark plugs. It's always recommended that you take the coach out and get it good and hot (freeway running) before you test. They'll test cleaner when hot.I don't know about Canadian smog tests, but my neighbor has been having a hard time getting his 2008 Ford V-10 to pass. The smog tech was entering it as a 10K GVW. My neighbor argued that it was a 20K chassis, but the tech said it didn't matter. He finally took it to another shop and they tested it as a 20K chassis and it passed.

you say to rich what are the numbers is it a tail pipe test. do you know somebody that has a scanner so you can see data on bank 1 and bank 2 look for fuel trim levels should be around 0 plus or mineus 3 if one bank is off that's wear your problem is sometimes o2 sensers can be bad and not throw a code

DSDP Don wrote:That engine in a motor home was known for eating up spark plug wires due to a lack of air flow across the wires and manifolds. I would make sure they're performing like they should. If they they're the OEM wires, I would replace with a good quality high temp set, along with new spark plugs. It's always recommended that you take the coach out and get it good and hot (freeway running) before you test. They'll test cleaner when hot.I don't know about Canadian smog tests, but my neighbor has been having a hard time getting his 2008 Ford V-10 to pass. The smog tech was entering it as a 10K GVW. My neighbor argued that it was a 20K chassis, but the tech said it didn't matter. He finally took it to another shop and they tested it as a 20K chassis and it passed.I've just replaced my second set of plugs and spark plug wires. One set in 2011 at 8,000 miles, and another set this year at 36,000 miles. Part of each set of wires had failed due to probable excessive manifold heat. The most recent repair did identify a manifold leak, which was also repaired, and high temp spark plug wires were installed. It certainly runs better now.

help my 8.1 engine will not pass emissions test in canada

12 Replies

free_radical
Explorer
May 07, 2016
And if all that doesnt help,,see Scotty Kilmer channel on YT
Mech with 45 years experience..
koda55
Explorer
May 07, 2016
I would get 5 cans of seafoam and pour four in the gas tank. I would disconnect a suction line and let it suck the can fifth can of seafaom out and shot off the engine. Let the engine set for 30 minutes. When you start it back up it is going to smoke excessively. After drive it around for a few miles and it will clear up. I did this with my f53. I also use seafoam in my diesel pusher and all my gas equiptment.
J-Rooster
Explorer
May 06, 2016
JC, before I retired at work (I'm a retired truck driver) he had a diesel motor that couldn't pass inspection. Our mechanic had me drive this truck until it warmed up then I drove it into the shop and our mechanic had me max out the engine RPM (told me not to let off the throttle) then he poured 1 quart of transmission fluid somewhere into the engine I couldn't see where need help here! And it cleaned up the emissions to where it passed with flying colors!
allbrandauto
Explorer
May 06, 2016
yes it could be maf sensor the data on bank 1 and 2 will tell you that if both are off yes
allbrandauto
Explorer
May 06, 2016
ArchHoagland wrote:
You need to clean your MAF. The Mass Air Flow sensor determines the air to fuel mixture and, when dirty, will cause Check Engine Lights,etc.

It is located right after the air filter, which should be changed at the same time.

Use MAF spray cleaner, about $10.
Oldtymeflyr
Explorer
May 06, 2016
Take it to a GM shop. No one knows GM engines better than GM.
ArchHoagland
Explorer
May 05, 2016
You need to clean your MAF. The Mass Air Flow sensor determines the air to fuel mixture and, when dirty, will cause Check Engine Lights,etc.

It is located right after the air filter, which should be changed at the same time.

Use MAF spray cleaner, about $10.
Pangaea_Ron
Explorer
May 05, 2016
DSDP Don wrote:
That engine in a motor home was known for eating up spark plug wires due to a lack of air flow across the wires and manifolds. I would make sure they're performing like they should. If they they're the OEM wires, I would replace with a good quality high temp set, along with new spark plugs.

It's always recommended that you take the coach out and get it good and hot (freeway running) before you test. They'll test cleaner when hot.

I don't know about Canadian smog tests, but my neighbor has been having a hard time getting his 2008 Ford V-10 to pass. The smog tech was entering it as a 10K GVW. My neighbor argued that it was a 20K chassis, but the tech said it didn't matter. He finally took it to another shop and they tested it as a 20K chassis and it passed.

I've just replaced my second set of plugs and spark plug wires. One set in 2011 at 8,000 miles, and another set this year at 36,000 miles. Part of each set of wires had failed due to probable excessive manifold heat. The most recent repair did identify a manifold leak, which was also repaired, and high temp spark plug wires were installed. It certainly runs better now.
allbrandauto
Explorer
May 05, 2016
you say to rich what are the numbers is it a tail pipe test. do you know somebody that has a scanner so you can see data on bank 1 and bank 2 look for fuel trim levels should be around 0 plus or mineus 3 if one bank is off that's wear your problem is sometimes o2 sensers can be bad and not throw a code
DSDP_Don
Explorer
May 05, 2016
That engine in a motor home was known for eating up spark plug wires due to a lack of air flow across the wires and manifolds. I would make sure they're performing like they should. If they they're the OEM wires, I would replace with a good quality high temp set, along with new spark plugs.

It's always recommended that you take the coach out and get it good and hot (freeway running) before you test. They'll test cleaner when hot.

I don't know about Canadian smog tests, but my neighbor has been having a hard time getting his 2008 Ford V-10 to pass. The smog tech was entering it as a 10K GVW. My neighbor argued that it was a 20K chassis, but the tech said it didn't matter. He finally took it to another shop and they tested it as a 20K chassis and it passed.