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91 z28 305 headers question

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Old May 20, 2008 | 11:33 AM
  #1  
mike83camaroBA's Avatar
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Default 91 z28 305 headers question

if i install headers and get rid of all the smog crap, will me check engine light go on? im not worried about passing inspection i just dont want to drive around with the light on because that would annoy me. any input would be appreciated
 
Old May 20, 2008 | 01:38 PM
  #2  
blackz87's Avatar
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Default RE: 91 z28 305 headers question

If you get rid of what you call" smog crap". I would say yes, the SES light is going to shine on you.
 
Old May 20, 2008 | 04:04 PM
  #3  
Camaro 69's Avatar
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Default RE: 91 z28 305 headers question

A cold engine runs richer (fuel) than a hot engine, so the smog pump injects air into the exhaust manifoldsuntil it warms up to keep the emissions level down. There is also another injector pipe that goes into the cat. converter. On the passenger side, above the valve cover, there is an electrically controlled (solenoid) dual-valve unit that has a plastic cover held on with two tabs both top and bottom. There is also a riser pipe that hangs above the passenger side exhaust manifold that tells that unit when the engine is hot. I plan on taking "the smog crap" out of my 91 as well, mostly for cosmetic reasons. As a test, I disconnected both electrical plugs that go to the solenoids. So far, after two days, still no SES light due to having the electrical connections off. But in theory, now my smog pump should be pumping air in constantly since the solenoids can't switch off the flow. The next step will be to disconnect the hoses, and if it stays all clear, then I know I can safely remove it all. As far as I understand, removing the smog crap shouldn't set off an error code. We shall see.
 
Old May 26, 2008 | 08:26 AM
  #4  
mike83camaroBA's Avatar
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Default RE: 91 z28 305 headers question

ok cool, well keep me updated on that one, i also have a question about modifying the stock exhaust. every set of headers i have looked at says if i want to keep the cat i have to modify the stock exhaust has anyone done this yet or do u just take out the cat?
 
Old Jun 14, 2008 | 09:08 AM
  #5  
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Default RE: 91 z28 305 headers question

Mike, I did eliminate all smog and computer input on a '91 RS by swapping an '84 305 in place of the FI V6. I did however keep the computer hooked up to control the lockup function and also on the '91 the speedo must have computer input to register on the guage. Now to your question; yes the light will come on but I removed the instrument cluster and took out the light bulb. I'm not sure how far you want to go with this but I'm very happy with my setup. Your biggest concern will be your engine timing advance/spark knock sensor since you will be removing all the inputs to the system. I have a vaccum advance D.U.I. dist to solve the timing issue.

Call me and I willhelp you in any way I can.

Roy,
248-807-4056
 
Old Jun 15, 2008 | 09:50 PM
  #6  
buckfever's Avatar
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Default RE: 91 z28 305 headers question

on my 87 my check engine light never came on and i removed every piece of emissions eqipment on my car.
 
Old Jun 16, 2008 | 03:35 AM
  #7  
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Default RE: 91 z28 305 headers question

Removing the "smog crap" absolutely DOES NOT trip your SES function. I removed my smog pump and all related hoses, plugged the exhaust manifold injector tubes, and my cat fell off too. But if you were to remove the oxygen sensor, then that's a different story.
 
Old Oct 14, 2008 | 07:04 PM
  #8  
xeet2050's Avatar
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Default RE: 91 z28 305 headers question

If you are going to get headers then i would go ahead and get a complete system.if you arnt gunna get like flowmasters all the way back or anything go with morso sprial flow racing mufflers. my frined has had nothing but good stuff to say about them. and it sounds like a beast too.
 
Old Dec 6, 2008 | 08:47 PM
  #9  
c4maro's Avatar
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Default RE: 91 z28 305 headers question

It dident go on inmy 87 z28 305.
 
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