Car Smog Question

[PastaPilot 17]

I have a 1996 Mustang with 97,000 miles that I drive about 3,000 miles per year now but over the past 6 years has been getting closer and closer to failing a smog check.

It has a myriad of bolt on performance parts and breezed through a smog check in 2006 when I installed a new Bassani catalytic exhaust. Since then the HC emissions at 1500RPM have slowly crept up. I've tried new plugs, injector cleaners and oil and what not in the past and am concerned (again) it won't make it through this year.

I'm now looking again at new spark plugs (haven't replaced them in ahile) and ignition coil packs to try and freshen up the ignition system. I am also considering new fuel injectors, but don't want to waste the money if it won't help. Also considering a dyno tune to clean up any low RPM fueling issues. Money is an object on this one.

Aside from registering it out of state, any advice?

[TrophyHunter 15]

You mentioned injector cleaners - "dump a bottle in the tank" kind?

I did the "direct into the fuel line just prior to the injector" kind on a 240SX I had and it was a noticeable performance difference. Don't know how that affects smog reads, though.

[Vacman 0]

Make sure you get the cats screaming hot before the test. On my m5, it wouldn't pass if it sat before the test. However, if I drove to the test in a spirited fashion, let it idle outside while waiting and then test, it breezed through every time. Same thing with my Land Cruiser.

[darylhunter 1]

My old Bronco II used to have a tough time (1984, last year with a carb). The shop I took it to told me to put some cardboard in front of the radiator and get it really hot before I brought it it.

That model was always difficult apparently and needed all the heat in it you could get in order to pass.

[KTMrad 513]

Take it to Colin at Top Value Tire...he'll take care of you and very reasonable....he also is our official sponsor and sponsors the desert dash.

619-465-5444

[1NaAdv 4]

Clean maf and throttle body. Change plugs if due. Wouldnt hurt to check compression with plugs out if its idling rough.Use an injector additive, there is even a pass smog stuff you can add to your tank. Like vac said get the cats hot before the test. With that milage it should pass.

[PastaPilot 17]

Thanks for the replies. I ordered plugs, a new "CARB approved" K&N intake to replace my "illegal" cold air intake that nobody will check the car with and new MSD coil packs. It might help, we'll see.

My neighbor thinks it may have an air leak. When I got to thinking about it he may be right. In 2006, it passed easily and in 2007 I had the intake manifold replaced. In 2008 it barely passed a smog check.

I've tried the spirited driving and idled the car in the lot to keep the cats hot, but it's always taken the testers too long to do anything and doesn't seem to matter.

[1NaAdv 4]

Fords are notorious for air leaks, but are always for the most part accompanied with lean, maf, or o2 codes.

Are HC's the only fail?

[Bp619 104]

you should notice a big lack of power if your intake manifold is leaking. bad hesitation and idle. maintenance items like plugs and coils honestly wont change much to help for smog especially the coils. I would check for vacuum leaks first either the carb cleaner method just spray down intake while engine running or make your own smoke machine pretty creative stuff on youtube. other than that with a easrly obd2 car if the check engine light isn't on the sensor wont tell you much about whats wrong with it.

[PastaPilot 17]

Fords are notorious for air leaks, but are always for the most part accompanied with lean, maf, or o2 codes.

Are HC's the only fail?

The 1500RPM HC has been borderline for 6ish years.

I installed the new MSD coil packs last night and I swear it runs better. I know it could be me mentally justifying the $145 but it used to shudder badly when taking off from a dead stop and didn't seem to do it as much on the test drive. The shuddering in the drivetrain started or got much more noticible with the billet alluminum flywheel and HD clutch I installed in 2003.

I'd be installing the new Bosch plugs right now, but found a torn radiator hose that I can't get to come off the damned engine. Maybe the new hose will be the one that gets it to pass?

[1NaAdv 4]

Fords are notorious for air leaks, but are always for the most part accompanied with lean, maf, or o2 codes.

Are HC's the only fail?

The 1500RPM HC has been borderline for 6ish years.

I installed the new MSD coil packs last night and I swear it runs better. I know it could be me mentally justifying the $145 but it used to shudder badly when taking off from a dead stop and didn't seem to do it as much on the test drive. The shuddering in the drivetrain started or got much more noticible with the billet alluminum flywheel and HD clutch I installed in 2003.

I'd be installing the new Bosch plugs right now, but found a torn radiator hose that I can't get to come off the damned engine. Maybe the new hose will be the one that gets it to pass?

The shudder is the light flywheel, the oe one feels smoother due to more rotating mass.

Theoretically it could be running smoother with the new coils if they produce more spark, that would lead to beleive your current plugs may have too big of gaps due to age. I would put oe plugs in it. Sounds like they are due.

[PastaPilot 17]

Here's more info on the car.

When the car was newer I replaced the OE plug wires with these aftermarket wires. The manufacturer claimed that due to the significant drop in resistance through the wires the gap on the plugs could be increased. So I did. I also tested the resistance on the wires and was amazed at how much lower the value was. I remember comparing the longest AM wire to the shortest OE wire and the aftermarket was like 10% of the OE. It was an impressive difference.

At some point I also installed copper core plugs and thought they were still in the engine so I ordered replacements. When I pulled the first plug I found motorcraft premium platinum plugs that looked almost new. I must've intalled those before the last smog check and forgot about it. The new plugs turned out to be for a V6 engine so I replaced the old one and buttoned it up.

Now, I'm just waiting on a new heater hose.

I may change the trans and differential oil while I wait.

[carguy 1]

Berrymans B-12 carb cleaner, liquid, 3 cans in the tank

[PastaPilot 17]

thanks again to everyone for the suggestions. I finally got the car checked. It passed, but barely. I tried everything, but the 1500 RPM hydrocarbon check is right at the upper limit and it puffs a little white smoke when stepped on. Over the next 2 years I may replace the cat pipe or just register it at my dad's house in Ohio.

[Beta450 0]

Rent a po box in El Centro and you only have to smog it once.