Air injection
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Freshman User
Joined: Jul 2003
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From: Idaho
Air injection
I was wondering if there was anyway to get rid of the cylinder head air injection on my truck. The little injection pipe is not only rusted all to heck but it is also really loose. Is there anyway I can just put some bolts in the holes in the head or something? Thanks for all the help!!!!!
Scott
Scott
Senior User
Joined: Dec 2003
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Your cats may plug up - and if you ever move anywhere where they do emmission testing you will have to fix everything you alter now. I hate air injection but I service it until it can't be serviced any longer - sounds like yours just needs a $35-$50 pipe.
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Joined: Jul 2004
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From: St. Louis mo
I also have a 96 f150 and i was wondering the same thing. My air injection setup however, is not rusted, but i was wondering if there are any hp or torque gains that may come along with removing the air injection system. (i also thought about modifying the extisting air injection ports to water injection. any info or feedback would be appericiated
Posting Guru
Joined: Nov 2003
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From: Sussex County, DE
The air injection ports in the head are not neccessary for passing a sniffer test on a warm engine, since the diverter valve pumps air directly to the cat when the engine is at operating temperature. The purpose of AIR in the cylinder head is to reduce cold start emissions. That means a 1996 truck with OBDII might set a trouble code if the O2 sensors don't see a fluctuation in voltage when the diverter valve pumps air into the head (OBD I will not have this problem). As far as smog testing is concerned on 1995 and earlier, as long as the converter air supply remains hooked up, you'll pass just fine and not run the risk of clogging your converter. As for H2O injection, that won't work, you'd only be blowing water into the exhaust stream, with no benefit, as the water would never get to the combustion chamber.
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From: Meggett SC
Another thing the air injection does is it prevents backfiring. when you take your foot off the accelerator the air is switched from the cat to the head to prevent the engine from rapping and backfiring and ruining the cat.
With a EFI system ther is almost nothing you can do to improve performance unless you dumb the engine down. The computer is running the show based on the sensor inputs.
With a EFI system ther is almost nothing you can do to improve performance unless you dumb the engine down. The computer is running the show based on the sensor inputs.
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Senior User
Joined: Aug 2003
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From: clarks mills, PA
the holes are 9/16-18 not 1/2-20 just to let you know. im looking for set screws for mine know i guess ill haveto make a trip to the bolt store brecause the local hardware stopre only has set srews up to 1/2
Posting Guru
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From: Sussex County, DE
sail2244:
Actually the air is not diverted to the head during decel, it is diverted to either the air cleaner assembly or is vented through a small, gauze filled muffler. Diverting to the head on decel on a hot engine would burn the exhaust valves and could overheat the cat.
Actually the air is not diverted to the head during decel, it is diverted to either the air cleaner assembly or is vented through a small, gauze filled muffler. Diverting to the head on decel on a hot engine would burn the exhaust valves and could overheat the cat.
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From: Meggett SC
Argo
On my 84 f150 I6 the air goes to a check valve located on the carb spacer next to the egr valve. The port in the carb spacer goes into the heat riser of the exhaust manifold. On deceleration the thermactor air valve shifts and dumps air from the air pump to the exhaust manifold to prevent backfiring. I believe the throttle position sensor sends a signal to the computer whech then operates the TAB and TAD solenoids of the thermactor air system. On older and on newertrucks it dumps to the exhaust manifold thru ports downstream of the valves so it will not harm the valves.
The air exhausts thru the muffler only on engine warmup. This prevents the cat from getting too hot. when the engine is warm and you are driving it diverts to the cat.
On my 84 f150 I6 the air goes to a check valve located on the carb spacer next to the egr valve. The port in the carb spacer goes into the heat riser of the exhaust manifold. On deceleration the thermactor air valve shifts and dumps air from the air pump to the exhaust manifold to prevent backfiring. I believe the throttle position sensor sends a signal to the computer whech then operates the TAB and TAD solenoids of the thermactor air system. On older and on newertrucks it dumps to the exhaust manifold thru ports downstream of the valves so it will not harm the valves.
The air exhausts thru the muffler only on engine warmup. This prevents the cat from getting too hot. when the engine is warm and you are driving it diverts to the cat.
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Joined: Jan 2001
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From: TX
Does the Diverter dump the air to the cat or AFTER the cat? My Bronco has had substantial customization to the exhaust and now the air is pumped into my exhaust after the cat. This doesn't seem right based on pictures in my Haynes. Should I move the air port either into or right before the cat?
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Joined: Jul 2003
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From: Meggett SC
It actually dumps it in the middle of the cat. Origionally there was a precat then the cat it origionally dumped the air before the cat, not the precat, new converters seem to have two sections and the air is dumped in the middle
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