1973 - 1979 F-100 & Larger F-Series TrucksDiscuss the Dentsides Ford Truck
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I'm working on getting my egr operational in hopes of better fuel economy. All components were in working order except the amplifier. One of the diaphragm's was ripped so I picked up a second one and it had the same problem. I'm thinking this must be a common problem so figured I would try and fix them. I'm sure I could get the egr working without it but think it'll be better with the amplifier.
Here is the vacuum amplifier.
Here is the problem. The black diaphragm is ripped right off the little brass orifice. It should be pressed underneath therefore sealing up both sides separately.
I'm gonna patch it and re-press it under the orifice. You can drive out the orifice with a small nail or punch. Doesn't take much to pop it out.
One small tap and it's out. You can see the part of the diaphragm that was pressed underneath.
Next rough up the diaphragm where the patch will be glued on. I used 180 grit emery cloth.
Then apply rubber cement and let dry. Only takes a couple minutes to dry.
Press on patch.
Poke hole in center with a nail.
Push orifice through diaphragm and trim rubber away so it wont fold up under the orifice when you press it back together.
Ready to be pressed back together.
Light tap with the hammer and it's pressed in.
Ready to be screwed together.
Check to make sure it holds vacuum.
Two vacuum amplifier's ready for service.
I hope this will help someone get their egr working like it should. Tomorrow I should have it hooked up, carb leaned out and timing re-curved. I will let you know how I make out.
Port S and V should not commingle. If they do the diaphragm has a hole in it. All you need to do is blow in one of the ports and air shouldn't come out the other port. If the diaphragm is ripped it wont be able to open the valve and allow vacuum to pass through port R and O on the opposite side of the amplifier and then to the egr valve. When vacuum from the spark port on the carb is greater than vacuum from the venturi port on the carb the amplifier valve is opened allowing vacuum to the egr. Also between the amplifier and egr is a load control valve. It dumps the vacuum to the egr when venturi vacuum is present. I'm assuming all this complicated stuff is supposed to close the egr valve during idle and full power. I've been studying this for the past week but still don't have a complete grasp on it. Time to go to the shop and hook up vacuum lines. Wish me luck. Here is the diagram I'm gonna follow and a picture of the load control valve with amplifier.
Excellent write up. I would be curious to see how it affects your mileage. My EGR doesn't do squat as the plate is damaged and clogged up and so too does the intake seem to be. I really didn't care but if it could actually improve the mileage I might look into it.
Everything's hooked up and egr is working. Bumped timing up to 10° from 6° and no pinging. Use to ping with anything over 6°. Tried hooking up the vacuum advance and it started pinging. I can't figure that one out. It has a 26° reluctor so I should have 36° total. I don't have a tach but revved it pretty good and it only went up to 20°. Might try some weaker springs. Pulled out a spark plug and it was black(dry). I had 59 jets and dropped them down to 51. Now it misses on acceleration so will put in some 57's. Probably will still be rich so need to find some 53-55 jets. What do you guys have in your carb? Not sure how to check power valve vacuum but doesn't seem like it is leaking. I have 3 of them but not one has a color code on it. I'm sure I will improve my fuel mileage but now have done so much I will never know how much the egr helped. I guess it all works together though.
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