I have a 93 5.0 with 90k miles on it. It has two cats and I put new plugs and a new smog pump into it. I have a MSD 6AL box with a BBK cold air. I have a full exhaust with full length headers and a superchip. I keep failing on hydrocarbs pretty bad. I have failed 6 times and I dont know what to do! Please help me out if u can. email me if possible at [email protected]
I NEED EMISSIONS HELP WITH MY 93 5.0 PLEASE!!!!!!!!!!
- Thread starter TurbomanTSi
- Start date
91five-o
New Member
My car failed four times, each time I kept taking more timing out of itand the idle test kept getting better but couldn't get the reading low enough. My car was failing on the idle test only with hydrocarbons. The driving test passed with flying colors the first time through and actually kept getting better everytime i took more timing out of it. Anyway, the last time I failed, my timing was set at 2 degrees and that's when I gave up 
and took it to a shop. I was close but didn't want to keep wasting money. Long story short - the shop dropped the timing to 1 degree, idle at 1050 rpm and it passed. Hope this helps. 
Rick
Rick
donkey_punch
New Member
Michael Yount
Mustang Master
Guys is it possible this has anything to do with his longtubes and the O2 sensors being located too far away from the stock location? The LT's usually place the O2's a foot or two further back in the system. With more time for hydrocarbons to oxidize in the stream before reaching the O2's, they're seeing a leaner signal, and consequently the computer is injecting a bit more fuel than it should resulting in the higher HC reading. Just a shot in the dark.
two things come to mind:
1) IF you removed two cats: i don't remember which two do which, but one pair is for NOx and the others are for Hc and CO. this could be the prob. otherwise if you have an aftermarket pipe, disregard this.
2) what are your plugs gapped at? my first time through the sniffer i failed the Hc at idle. i was running ~.065-.069 (going from memory) with my jacobs. after i closed them down to ~.059 and had the re-test there were no issues.
1) IF you removed two cats: i don't remember which two do which, but one pair is for NOx and the others are for Hc and CO. this could be the prob. otherwise if you have an aftermarket pipe, disregard this.
2) what are your plugs gapped at? my first time through the sniffer i failed the Hc at idle. i was running ~.065-.069 (going from memory) with my jacobs. after i closed them down to ~.059 and had the re-test there were no issues.
Michael Yount
Mustang Master
Sleeper makes a great point - if you replaced dual cats with a single, it needs to be a 3-way cat - taking care of HC, NOx and CO.
Sleeper - would love to have details of which unit you have, and your impressions of your Jacobs ignition system. You can email me direct at [email protected] or pm me. Thanks in advance.
Sleeper - would love to have details of which unit you have, and your impressions of your Jacobs ignition system. You can email me direct at [email protected] or pm me. Thanks in advance.
stang&2Birds
Founding Member
Junk the car. 
Or, MORE INFO! It could be a ton of things. Without more info, you WILL end up junking the whole exhaust setup.
You need NEW O2 sensors, you need 3 way cats, you need the cats and o2 sensors to be hot enough, you must go into closed loop. Or, you need a good working EGR system. You need to have your timing right. And so on and so on. So, you can junk the car. Or, list (in a nice way) every thing about the test, the results, the standard, your car, the setup, etc.
Still, my guess is that there is very little chance you'll pass, in anyway, with your setup. Non coated long tubes are horrible for smog. They let out too much heat. The cats are too far down. Etc.
The superchip _should_ effect only WOT conditions. Unless, you have a custom *non smog legal* tune.
In short, you may have to put on the stock headers and h-pipe to pass. YOUR engine and the way it's tested in NOT the same as "joe blow" that passed with a million mods. Also, you'll NEED the smog pump working.
Can a stang pass with long tubes and no cats? Well, some people have. IMHO, they should have bought a lottery ticket with that type of luck.
BTW: Some states are now checking for the *number* of cats. More and more are. So, keep that in mind. A state can change smog testing procedures *anytime* they feel like it. An aftermarket h-x pipe is NOT smog legal. Never has been, never will be. But, it MAY pass SOME smog tests.
BTW#2: *I* did not make the laws, or create the laws of physics. So, don't complain to me. *I*, and many other, have to deal with the same thing.
Or, MORE INFO! It could be a ton of things. Without more info, you WILL end up junking the whole exhaust setup.You need NEW O2 sensors, you need 3 way cats, you need the cats and o2 sensors to be hot enough, you must go into closed loop. Or, you need a good working EGR system. You need to have your timing right. And so on and so on. So, you can junk the car. Or, list (in a nice way) every thing about the test, the results, the standard, your car, the setup, etc.
Still, my guess is that there is very little chance you'll pass, in anyway, with your setup. Non coated long tubes are horrible for smog. They let out too much heat. The cats are too far down. Etc.
The superchip _should_ effect only WOT conditions. Unless, you have a custom *non smog legal* tune.
In short, you may have to put on the stock headers and h-pipe to pass. YOUR engine and the way it's tested in NOT the same as "joe blow" that passed with a million mods. Also, you'll NEED the smog pump working.
Can a stang pass with long tubes and no cats? Well, some people have. IMHO, they should have bought a lottery ticket with that type of luck.
BTW: Some states are now checking for the *number* of cats. More and more are. So, keep that in mind. A state can change smog testing procedures *anytime* they feel like it. An aftermarket h-x pipe is NOT smog legal. Never has been, never will be. But, it MAY pass SOME smog tests.
BTW#2: *I* did not make the laws, or create the laws of physics. So, don't complain to me.
*I*, and many other, have to deal with the same thing.Similar threads
