Help I Think My Mechanic Is Try To Rip Me Off!

brokeSC

Registered User
HELP!!
Ok i have 2 questions i'm kind of new to the SC thing but not really i've had my car for 3 years..
Ok first Question Don't the 1991 SC's only have 2 Cat's? My mechanic is saying that he needs to replace my third cat?? to get me to pass inspection???

ok second Question
Why is my NoX level High every year! how do i fix this and what are other ways to lower your Nox level??

Thank you guy i came here because i know you guy know more about SC's then anyone else on the web
THanks!
 
YES. there are only 2 cats and a resonator. i think maybe some of the late models MIGHT have had 3 but dont quote me
 
so what should i do?

should i just let this guy try to replace a third cat thats not there??
or should i go there and pick up my car?
i even mentioned that to him "I'm pretty sure the '91 have 2 cat's and a resinator" and "you sure you don't mean the Resinator"

does the Resinator do anything for emissions??

And how the hell is my Nox level off the Chart Every YEAR!
 
Resonator

The Resonator doesn't do anything for lowering emissions. All it does is help to make the car sound a little meaner. all it does is just what the name suggests, it lets sound resonate inside of it.

I believe that the resonator is what the mechanic is referring to as your 3rd cat. Sounds like your mechanic doesn't know a whole lot about the cars. If you have any doubts, contact your local Ford parts counter, and ask them to pull up the exhaust system. They could tell you directly off the factory specs wether or not you do have that ellusive 3rd cat, or just the resonator.
 
found out i don't have a third cat..

I kind of knew that already but wasn't sure if i should doubt my mechanic for fear of making an a** of my self...

Ok so what other ways then replacing cat's is there to lower NoX levels??

Nitrous oxide right?
 
I believe you will produce more noXs if the car is running rich. When did it last have a tuneup, and what type of spark plugs were used? Check the oxygen sensors also. Check the tailpipes for black soot, it indicates a rich fuel mixture. If the vehicles operates rich too long, it can damage the catalytic converter. Some models also use a 3-way, single cat.

Also, don't be afraid to walk into the shop and have him show you the parts he is refering to while its on a lift. You are his customer, and he shouldn't have any problem with doing this. If he doesn't allow you to see it, I would go elsewhere.
 
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my car is a 94 tbird 5 speed my car had 3 cats one on each down tube are then y piped into the 3rd cat then into a resonator
 
cats

ok for certain:
you don't have 3 cats. that was not done until after 92, i think 93 was the beginning. Now, being a 91 you may have EGR. some early models still had it. An improperly working egr can make you have high NOx, no not nitrous oxide, thats go juice, its oxides of Nitrogen, no i don't know how to explain the difference. As for it running rich, what are your emmisions numbers. If you are running rich, you will show High HC (hydro carbons, unburned gas). for our cars all i can think of is a bad EGR. now, you may actually need to replace your 2 (two) cats. Have you blown the head gaskets, ever, that can destroy a cat, or if you used to run rich, it can screw up the cats too. do you hear any rattling noise from the exhuast?? Cats do deteriorate, maybe they are just old, are you near 200K miles, (not that this would neccesarily be a cause.)

give your numbers for all categories and maybe we can try to pinpoint a problem.

jim
 
The cars with EGR have a 2 way catalyst as the EGR is used to control NOx.

The cars without EGR have a 3 way catalyst that takes care of NOx.

NOx is caused by high combustion chamber temperatures. If your EGR valve is not working this could be a cause of high NOx.

I don't believe a bad 2-way Cat will cause any more NOx than a bad EGR valve. In other words the 2-Way cat plays no role in eliminating NOx.

Thus first find out of you have EGR. If you don't, it's possible that you have 2ea 2-way cats and 1ea 3-way cat.

Thus it would be the 3-way cat that has failed. Check out mn12peformance.com and the link below. They have pictures of the various exhaust configurations.


http://www.mn12performance.com/mn12-techinfo/exhaust/exhaust.htm
 
ok so the official numbers are in...

Ok so i brought it to another shop because that guy was a complete moron..
They ran the inspection again and i still failed..

Ok so these are the numbers that i got on my inspection..
Does anyone know how to Translate these??

CO 15 is the max allowed i got a 8.84 so i passed there
Nox 2.0 is the max allowed i got a 3.22 FAILED
HC .90 is the max allowed i got a .93 FAILED

How the h*** do i translate these numbers??
 
first off everything mike said is right. I can't confirm or deny that you have 2 or 3 way cats.

as for translation: heres my best shot, you said

CO 15 is the max allowed i got a 8.84 so i passed there
Nox 2.0 is the max allowed i got a 3.22 FAILED
HC .90 is the max allowed i got a .93 FAILED

Nox. out of range, cylinder temps too high, causes bad egr, running rich,
HC out of range, unburned fuel leaving cylinder, causes running rich.

now i just confused my self while thinking about this, NOx means too hot, but rich would cool the engine, like i've said, i'm no expert. maybe they are 3-way cats, and they are going bad.
Has your car ever seemed like it was missing or just didn't have full power when you get on the gas??? check your fuel pressure when your driving, if FPR is going bad, it could dump extra fuel in.

let us know, how many miles on your bird
the rest of the numbers from emission, O2 and whatever else there is, they can shed light on more details. maybe make a new post asking for more explanation of emission numbers, and put in there a link to this thread.

jim
 
hmmm...

I thought the early manual SC's had just 2 cats. And then, The manuals had 3. My 1991 has 2 cats (its an auto) and NO EGR. None of the autos did if i remember correctly. Not sure about the manuals tho. Just get a pict of your exhaust set-up wheter you have a manual or an auto and climb under there and look.
 
A california car could possibly have a different exhaust setup.

Look specifically for EGR. If you don't have it, you have three way cats. If you do have it, you don't have 3 way cats.

Any simple mechanic should be able to verify how many cats are on a car as cats are much more solid metal than resonators or mufflers. They also sound different when you whack them with a hammer.
 
nox

I just went through the exact same problem here in Ca. I passed everything but the nox. What I did was get some spray to clean out the carbon in the engine. I went back and failed again, but only by 1\2 as much (the nox level was cut in half). I got some cleaner that I put in through a vacuum line, brought it back and it passed. Normally, from what I am told by the emmissions people, it is the egr, i and you don't have one. Once I got the carbon out of the engine it passed. Have your mechanic (new mechanic, I hope) put in some kind of carbon cleaner. I had to get it from Ford, it was a three step system. If you have a problem email me and I will find out the name of what I used.
Ed
 
leading cause of converter failure

Is the O2 censor. second is the coolant temp censor. Straight form the horces mouth at Catco. When a converter goes out it is always helped by something else in the system. Coolant reads wrong so the computer never thinks its warmed up, Never warmed up it will never listen to the O2 censors cause it has to be warm to operate correctly. over rich, super lean, antifreeze, silicon, all spell doom for both o2 and converter.
 
cats?!

i have a 91 sc 5 speed there are only 2 cats on your car not 3 there is a res but no thrird cat as for the nox i have no idea but i can tell you that your sc does NOT have a third cat tell your mec he is smelling too many Fumes!!
 
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