stuck EGR valve help please
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stuck EGR valve help please
Hi everyone,
I have a 1987 F150 and I have been trying to figure out why I have been getting such poor gas mileage. It has a 302 automatic. The mileage has dropped from 15-16 to 9-10. It has a fairly new tune up (plugs,wires and new o2 sensor). I decided to check all of the control componets and fuel. I found the EGR valve is stuck shut and since it has feed back to the computer I was wondering if it might affect the mileage. Also when I was checking the fuel pressure. I noticed that when I shut the engine off the pump pressure would continue to rise to about 45 pounds.
Does anyone think that either one of thes would affect the mileage?
I have a 1987 F150 and I have been trying to figure out why I have been getting such poor gas mileage. It has a 302 automatic. The mileage has dropped from 15-16 to 9-10. It has a fairly new tune up (plugs,wires and new o2 sensor). I decided to check all of the control componets and fuel. I found the EGR valve is stuck shut and since it has feed back to the computer I was wondering if it might affect the mileage. Also when I was checking the fuel pressure. I noticed that when I shut the engine off the pump pressure would continue to rise to about 45 pounds.
Does anyone think that either one of thes would affect the mileage?
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From: Erie, Pa.
(96, 5.0) I get the same mileage (about 9 mpg) with a code pointing to EGR flow. I replaced the EGR solenoid for about 90 bucks because a mechanic's high tech $5000 computer said to. After that, I could not afford an EGR valve.
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From: Easton,Ks
Originally Posted by Lesspaul
(96, 5.0) I get the same mileage (about 9 mpg) with a code pointing to EGR flow. I replaced the EGR solenoid for about 90 bucks because a mechanic's high tech $5000 computer said to. After that, I could not afford an EGR valve.
If the EGR valve is not opening I have heard that you would have a richer mixture and poorer gas mileage. But I would not think it would drop it that far. Also there is a code that the PCM will through if EGR valve is not doing what the PCM told it to do. Use a hand vacuum pump to check the EGR valve.
I think you help pay for his high tech $5000 computer.
Last edited by subford; Feb 26, 2006 at 11:20 AM.
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From: Erie, Pa.
Now that you mention it, I remember he used vacuum to test the egr and pointed to the egr solenoid or whatever that thing is. I replaced it and it looked nice and shiney. That's about the only thing positive it did. I need an EGR valve. I'm not sure if his $5000 computer pointed it out. I could barely understand him through his middle-eastern accent and broken english. I could hear him clearly say " cost you 35 dollar ".
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From: Easton,Ks
Originally Posted by Lesspaul
Now that you mention it, I remember he used vacuum to test the egr and pointed to the egr solenoid or whatever that thing is. I replaced it and it looked nice and shiney. That's about the only thing positive it did. I need an EGR valve. I'm not sure if his $5000 computer pointed it out. I could barely understand him through his middle-eastern accent and broken english. I could hear him clearly say " cost you 35 dollar ".
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From: Easton,Ks
Originally Posted by cat1947
Hi everyone,
I have a 1987 F150 and I have been trying to figure out why I have been getting such poor gas mileage. It has a 302 automatic. The mileage has dropped from 15-16 to 9-10. It has a fairly new tune up (plugs,wires and new o2 sensor). I decided to check all of the control componets and fuel. I found the EGR valve is stuck shut and since it has feed back to the computer I was wondering if it might affect the mileage. Also when I was checking the fuel pressure. I noticed that when I shut the engine off the pump pressure would continue to rise to about 45 pounds.
Does anyone think that either one of thes would affect the mileage?
I have a 1987 F150 and I have been trying to figure out why I have been getting such poor gas mileage. It has a 302 automatic. The mileage has dropped from 15-16 to 9-10. It has a fairly new tune up (plugs,wires and new o2 sensor). I decided to check all of the control componets and fuel. I found the EGR valve is stuck shut and since it has feed back to the computer I was wondering if it might affect the mileage. Also when I was checking the fuel pressure. I noticed that when I shut the engine off the pump pressure would continue to rise to about 45 pounds.
Does anyone think that either one of thes would affect the mileage?
It might also take care of you poor mileage.
As for the EGR Valve if is stuck, change it, if not I think we have covered it.
Good Luck and welcome to FTE.
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Thanks for all of the input. I was planning on changing the egr valve. I was just wondering if it would affect the fuel mileage.
As the fuel pressure goes. The running pressure is 35-40 lbs. It just goes up after the engine is shut off.
Thanks again
CaT
As the fuel pressure goes. The running pressure is 35-40 lbs. It just goes up after the engine is shut off.
Thanks again
CaT
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Junior User
Joined: Jan 2006
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From: North Royalton, Ohio
My fuel pressure goes up too, aft the engine is shutoff, I think that it is because, when the engine is off, it is not useing any fuel, the back pressure in the line before the regulator, bleeds forward and equals out the whole feul system. I would think, as long as your pressure holds steady while running you should be fine. (my opinion. lol)
As for the egr valve, subford is right, the only code reading you can get from it is "EGR valve opening not detected" You have to examine it carefully. Checked vaccum hoses before and aft the egr vac selenoid. easy way to check to see if you have any vaccum at all aft the selenoid, is to drive the truck for about 5 mins, come home, leave it running, disconnect the vaccum line from the egr valve and put finger over it, or listen to it. If you have any kind of vaccum at all, then you'll hear it. if not, you feel it or hear it. I just went through the whole egr thing myself, and without this site and I believe it was subford, I don't think I would have found it.
My egr was bad, but I never knew there was a selenoid until here, and it turned out that it wass bad too.
As for the egr valve, subford is right, the only code reading you can get from it is "EGR valve opening not detected" You have to examine it carefully. Checked vaccum hoses before and aft the egr vac selenoid. easy way to check to see if you have any vaccum at all aft the selenoid, is to drive the truck for about 5 mins, come home, leave it running, disconnect the vaccum line from the egr valve and put finger over it, or listen to it. If you have any kind of vaccum at all, then you'll hear it. if not, you feel it or hear it. I just went through the whole egr thing myself, and without this site and I believe it was subford, I don't think I would have found it.
My egr was bad, but I never knew there was a selenoid until here, and it turned out that it wass bad too.
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From: Easton,Ks
When you shut off the engine and you have a tight (no leaks) fuel system and the vacuum goes to zero the heat from the engine can heat up the fuel manifold and increase the pressure. No vacuum means higher fuel pressure. Here are three diagrams of the regulator and manifold.
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From: Easton,Ks
Originally Posted by RJPstruck
Checked vaccum hoses before and aft the egr vac selenoid. easy way to check to see if you have any vaccum at all aft the selenoid, is to drive the truck for about 5 mins, come home, leave it running, disconnect the vaccum line from the egr valve and put finger over it, or listen to it. If you have any kind of vaccum at all, then you'll hear it. if not, you feel it or hear it.
When the engine is idling there should be no vacuum in the hose to overcome the spring on the EGR Valve, it should be closed.
Here is a diagram of the valve.
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I was just wondering if the stuck egr valve would hurt the mileage. I know it is stuck because I put a hand vac pump on it and it wouldn't move. I checked that by measuring the resistance on the sensor . The sensor works because I took it off and pushed the plunger back and forth to check the sensor and it was alright.
Thanks
CaT
Thanks
CaT
Junior User
Joined: Jan 2006
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From: North Royalton, Ohio
Subford, my egr selenoid stays on for about 30sec to 1 min aft I have stopped the truck, with the engine still idleing. Why, I don't know. If this is a problem, what is wrong. No High idleing going on either. I know this buy useing a magnahelic guage.
Sry, i am not trying to take over this thread.
Cat1947, When I replaced my egr, I didn't see any increase in gas milage. I still get between 9-11 mpg. But I have a 351.
Sry, i am not trying to take over this thread.
Cat1947, When I replaced my egr, I didn't see any increase in gas milage. I still get between 9-11 mpg. But I have a 351.
Fleet Owner
Joined: Aug 2005
Posts: 23,667
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From: Easton,Ks
Originally Posted by RJPstruck
Subford, my egr selenoid stays on for about 30sec to 1 min aft I have stopped the truck, with the engine still idleing. Why, I don't know. If this is a problem, what is wrong. No High idleing going on either. I know this buy useing a magnahelic guage.
Sry, i am not trying to take over this thread.
Cat1947, When I replaced my egr, I didn't see any increase in gas milage. I still get between 9-11 mpg. But I have a 351.
Sry, i am not trying to take over this thread.
Cat1947, When I replaced my egr, I didn't see any increase in gas milage. I still get between 9-11 mpg. But I have a 351.
Take a look here, it is a run down on its operation.
http://fordfuelinjection.com/index.php?p=43
