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-   -   Mystery Pipe/tube question (http://www.f150forum.com/f10/mystery-pipe-tube-question-192935/)

Ford 4x4 02-01-2013 04:54 PM

Mystery Pipe/tube question
 
Hey guys, so the other day I cut the cats off my 89 f-150 5.0. I was cutting off the cats, and right behind the second cat (resonator maybe) there was a metal tube that was welded into the exhaust....

I cut it off from the exhaust, and never welded it into my new exhaust, it just hangs by it. It looks like it goes up to the back of the motor on the passenger side, but I did not follow it anymore than that.

I was just curious what this tube was, and I do not have pics :(

PS- I drove the truck a few miles home after I did the exhaust. The next day it was very cold -15 at least. The check engine light stayed on all day. I put oil and antifreeze in so I knew those were good. The truck runs great when the light is on... what would cause this.

Finally the check engine has come on and off for a few years now. It only happens when it is cold (maybe below 30) and only flashes on and off when you acellerate. I thought it was an intake gasket, so I put stop leak in and it still does it. Any ideas? Thanks guys

Ace12ace12 02-01-2013 06:32 PM

I think it's for the egr valve.

13Harleyfan 02-01-2013 06:53 PM

I believe that tube feeds back to the air pump. Someone correct me if I'm wrong. As far as the check engine light,anytime you start disconnecting or removing things that are related to emissions it's not unusual to see the light come/stay on. It might feel like it's running fine but you are probably wasting fuel.

Moose_God 02-01-2013 07:32 PM

It's the AIR injection tube...I broke mine while removing it to install headers....got a new tube from rock auto but can't seem to find anyone who sells a weld-in bung for the exhaust side.

Ford 4x4 02-01-2013 08:09 PM

Sweet, but I don't actually need it do I? I know on my 4.9 I had the local muffler shop put new exhaust on it and he just left it disconnected, I have not had any CEL or performance problems

snipe1605 02-01-2013 09:47 PM

Its the egr tube it goes into the crossover pipe on the back of the heads which is fed cool air from the air pump. Just remove the tube, crossover tube, plug the vacuum line on top and delete the air pump. If your state requires emissions then you must leave that stuff on and replace the the egr tube. It sticks into a rubber tube behind the motor and then welds into the exhaust pipe before the cats but after the 02 sensor. Make sure if you delete the air system to plug the holes on the back of the heads.

KentuckyCountryBoy 02-01-2013 10:05 PM

Quote:

Originally Posted by snipe1605 (Post 2391608)
Its the egr tube it goes into the crossover pipe on the back of the heads which is fed cool air from the air pump. Just remove the tube, crossover tube, plug the vacuum line on top and delete the air pump. If your state requires emissions then you must leave that stuff on and replace the the egr tube. It sticks into a rubber tube behind the motor and then welds into the exhaust pipe before the cats but after the 02 sensor. Make sure if you delete the air system to plug the holes on the back of the heads.

No, the EGR connects the lower intake on a 5.0 or the exhaust manifold on a 5.8 (idk about 4.9) to the EGR valve on the upper intake, right behind the throttle body. The piece the OP is refering to is the AIR pipe. If he deleted the cats, I'd just delete the tube too. Unless the truck has two O2's the exhaust mod should have nothing to do with the CEL.

Ford 4x4 02-01-2013 10:07 PM

Quote:

Originally Posted by KentuckyCountryBoy (Post 2391655)
No, the EGR connects the lower intake on a 5.0 or the exhaust manifold on a 5.8 (idk about 4.9) to the EGR valve on the upper intake, right behind the throttle body. The piece the OP is refering to is the AIR pipe. If he deleted the cats, I'd just delete the tube too. Unless the truck has two O2's the exhaust mod should have nothing to do with the CEL.

I did delete the cats, how do I delete the tube? where should I block the tube? The truck just has 1 02 sensor.

Just call me Sean 02-01-2013 11:14 PM

EGR on the 4.9 connects to the rear exhaust manifold.

That is the air injection pipe, and without cats it isn't needed. It also won't cause a check engine light just being disconnected there. Just remove the rest of it. Check for codes.

snipe1605 02-02-2013 07:01 PM

Oh yes your right its the air tube, but to delete the system you need to delete the crossover tube on the back of the heads and delete the air pump. It wont set off the cel but you will get a code for the air system not working. If you dont remove it all you will have an exhaust leak there.


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