EGR Valve question

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Sep 2, 2004 | 09:23 PM

mrgomerpyle

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From: Boise, ID

EGR Valve question

I have an 86 f150 I6 4x4 .. My question is this: It seems i have a vaccume leak somewhere so i was spraying some starter fluid around the carb to see if it changed at all and it didnt. I sprayed it on the EGR valve and it made a major change. Is that normal or does that mean that its bad and needs to be replaced? I am not sure how the egr valve works but it looks like there is a boot on the back side closest to the carb and when i sprayed the fluid on the boot is when the truck settled down. What do yall think? I am kinda hoping that it is the EGR valve so i can get on with my life..lol

Thanks
Bill

Sep 2, 2004 | 09:42 PM

Lee Lichterman

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From: Edwards Air Force Base

I am assuming you were at idle when you sprayed it so in that case, the EGR valve should have been completely closed. I am not sure what boot you are talking about but you either have an EGR valve that is not closing all the way or the vacuum line to operate it is leaking.

I would change the vacuum line and then if that doesn't do it, pull the EGR and clean it out real well. Most of the time, you can salvage your old one with some patience, some WD-40 and a lot of scraping. Most of the time, it is just a build up of carbon keeping the tapered rod from seating all the way. However if the rubber diaphram is old and cracked or you knick it while cleaning it, then you will have to replace it.

Good Luck,

Lee

Sep 3, 2004 | 09:53 AM

mrgomerpyle

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From: Boise, ID

The truck was sort of at idle when we sprayed it. I cannot keep it running without stepping on the gas pedal so when i say it was sort of at idle its because my foot was on the pedal but was running about where it should be when its at idle. I guess its not really a boot but you understand what i was talking about. We sprayed all the lines and it didnt do anything but when we sprayed the back of the EGR vavle it made a big difference. I guess i thought it was a boot because thats what it looks like. So you think it may be stuck? I will pull it out tomorrow and see what i can do. One more question. We took the little hose off of it and i put my finger over the hole and closed the valve and it opened right back up. Should there be a vacuum there? It didnt seam to do anything? I really dont know anything about EGR valves.

Thanks for your help
Bill

Sep 3, 2004 | 06:41 PM

Lee Lichterman

Elder User

Joined: May 2004

Posts: 506

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From: Edwards Air Force Base

Quote:

Originally Posted by mrgomerpyle

We took the little hose off of it and i put my finger over the hole and closed the valve and it opened right back up. Should there be a vacuum there? It didnt seam to do anything? I really dont know anything about EGR valves.

Thanks for your help
Bill

The EGR opened by itself with the hose off? It should be closed unless the hose is sucking the diaphram up. Don't know how it could open without vacuum pressure since it is spring loaded to close. Either you have a bad EGR or you have some gremlins pushing up on the stem of the EGR. -ggg- Sorry, couldn't resist. I have no idea other than a bad EGR what it could be. I don't see anyway the manifold could be pushing instead of sucking.

Maybe someone else could chime in. Off the top of my head, one thing that popped in but I doubt would be excessive back pressure in the exhaust overwhelming the valve but I have never seen it. Plausable but doubtful.

Also, how did you close the valve? Pictuing it in my head, closed is normal and when you push on it to move it, you are actually opening the valve, not closing it. Are you sure you aren't really opening it and not closing it thus it is operating correctly? In other words, when you push on the valve, you are opening it and the spring is doing what it is supposed to and closing it again.

Lee