thermactor air system
- Thread starter rocepp
- Start date
BlackVert
15 Year Member
18mustangs
New Member
rocepp said:
That's the smog tubes that run into the back of the heads (the smog tube that runs to the h-pipe adds air (the catalyst) to the catalytic converters in order to work properly to reduce emissions as well). Bank 1 and 2 are the left and right sides respectively. 96 on up are computer controlled where are 95 and down are purely mechanical. The smog system only controls emissions during the first 20-120 seconds of engine startup by injecting air into the exhaust ports to burn unused hydrocarbons caused by rich starting conditions. Haynes didn't say if it'd have anything to do with missing, but I doubt it.
--Tim
BlackVert
15 Year Member
the guys here say that the thermactor pumps air to the cats all the time, not just the first 2 minutes ...
http://forums.stangnet.com/showthread.php?t=553202
http://forums.stangnet.com/showthread.php?t=553202
BlackVert
15 Year Member
apparently, if the cats don't get enough oxygen, they can clog up after driving for 30 minutes or so, causing a restriction that can kill performance. this may cause the behavior that seems like a miss to you. after the car sits for a while, the cats unclog and then it runs ok again.rocepp said:
18mustangs
New Member
BlackVert said:
I was just quoting the Haynes book on that one. I think on the mechanical ones (95 and below) do blow all of the time. However, on the computer controlled 96 and up cars I think the book was saying that the thermactor blows for the first 20-120 seconds, and his car was a 96.
As the thread link you posted stated the air is always pumping into the cats (the catalyst to break down the unburned HCs), it's whether or not it goes into the thermactor ports in back of the heads all of the time that the book said 20-120 second during startup.--Tim
mo_dingo
20+ Year Stangneter 
The ports in the back of the heads are for the EGR, not the smog pump. Two different systems.
Scott
Scott
18mustangs
New Member
mo_dingo said:
EGR comes up through the center of the heads then through the center of the intake manifold on a Fox body (hence the little metal lined round hole in the center of the upper to lower intake gasket for a fox) to the EGR valve, and up from the header into the EGR valve then into the intake elbow on an SN95. There is no exhaust gas to be recirculated via the ports in the back of the head (the pump blows into the head, it doesn't suck exhaust gas out of the exhaust port to be recirculated). The ports in the back of the head are connected to the silver tube (that is connected to both heads) which is connected to the smog pump via a rubber hose with valves and vacuum lines on it. The smog pump pumps clean air into these holes which go into the exhaust ports of the heads to burn as much unburned hydrocarbons as possible in order to reduce emissions. Then what's still unburned goes to the h-pipe from the headers with the exhaust and is catalyzed a final time at the cats where the second line from the smog pump blows clean air into the cats in order for them to catalyze the remainin unburned hydrocarbons to reduce emissions further.
--Tim
18mustangs
New Member
rocepp said:
That could be the reason, do you have the MIL (malfunction indication light) eliminators on your O2 sensors? I'm not an expert on 96 and up, but I know that my friends had to run them on their 4.6s when running without cats.
http://store.summitracing.com/defau...earchinresults=false&N=0&target=egnsearch.asp
--Tim
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