smog equip removal

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Mar 6, 2015 | 07:51 PM

shnazdabling

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smog equip removal

Live in a state where emissions are no longer required as this awesome truck is over 20 years old.
I am desperately looking forward to removing all this archaic, underperforming, hp draining equipment now that it is legal to do so.
I have a 1991, F250, 5.0. Does anyone have any information on how to remove this emissions equipment? There's no way I'm the first person to do so. I suspect I could eventually figure it out on my own. But, I also suspect I would likely make several mistakes along the way unless someone is willing to provide some mentorship.
Anyone willing to help?

Mar 6, 2015 | 08:15 PM

Tedster9

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Joined: Apr 2002

Posts: 19,311

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From: Waterloo, Iowa

Are you sure it's legal? Anyway, the problem is by '91 the systems are so embedded I'd expect you have quite a task on your hand.

Mar 6, 2015 | 08:34 PM

Redneckfordf2502002

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Joined: Mar 2011

Posts: 10,080

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From: Backwoods of Snowflake AZ

This is the thread I am following while doing it smog delete on my 88:
https://www.ford-trucks.com/forums/1...-302-5-0l.html

Trav

Mar 6, 2015 | 09:00 PM

Conanski

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Joined: Jun 2006

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From: Ottawa, Ontario

Quote:

Originally Posted by shnazdabling

You can delete the whole smog(air injection) system without issue by simply following the lines back from the pump, this system makes up most of the mess under the hood of these trucks, just make sure the TAB and TAD solenoids near the coil remain electrically connected. The EGR is a very simple system in comparison just 1 tube from the passenger side exhaust manifold up to a valve that connects to the upper intake just behind the throttle body. This system can't be eliminated without setting codes and actually helps the engine get better fuel milage but do what you like. Removeing all this will definitely clean up the engine bay but it won't make any difference in power unless the air pump was partially seized.

Mar 6, 2015 | 09:13 PM

fordboy97

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Joined: Aug 2014

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Conanski I have deleted my egr and I have no CEL. I haven't checked for codes after the egr delete but I don't see how it would know. That is on my '90 though I believe on the newer trucks it is impossible to delete it without throwing codes.

Mar 6, 2015 | 09:14 PM

fordboy97

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Joined: Aug 2014

Posts: 389

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Quote:

Originally Posted by Redneckfordf2502002

This is the thread I am following while doing it smog delete on my 88:
https://www.ford-trucks.com/forums/1...-302-5-0l.html

Trav

Wow, that guy has a beautiful engine! Lol.

Mar 15, 2015 | 11:45 AM

shnazdabling

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Thank you guys for all the info. Though there seems to be a few ways to go, this info is exactly what I needed. BTW, it is legal in North Carolina as the vehicle has aged beyond the emissions test requirements. It only requires a yearly safety inspection.

Really appreciate the excellent guidance. Thanjs everyone.

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Mar 15, 2015 | 11:58 AM

Conanski

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Joined: Jun 2006

Posts: 31,930

Likes: 1,499

From: Ottawa, Ontario

Quote:

Originally Posted by fordboy97

Conanski I have deleted my egr and I have no CEL. I haven't checked for codes after the egr delete but I don't see how it would know.

You will have a code for sure if you pull them but it may not set the check engine light, earlier trucks probably won't get a CEL from this while later trucks will because of changes in the way the computer is programmed. In all cases there is no way* to totally delete the EGR without setting a code.. even with the little plug that is supposed to fool the computer. The reason is the computer both commands the valve to move via vacuum from the EGR solenoid and watches for the resulting movement at the EGR position sensor, so even if you trick out the position sensor that won't stop the computer from sending commands to make the valve move and when the reading from the position sensor doesn't change it thinks there is a problem and sets a code.

* Well there is 1 way to prevent codes.. get a tuner and turn off all EGR functions in the computer.

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Mar 15, 2015 | 12:38 PM

'89F2urd

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Joined: May 2011

Posts: 5,775

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you can leave the egr in tact, and plug the ends of the tube both on the lower intake and at the valve itself. this will give you the benefits of no egr and not keep the computer happy in the process.