Could someone please explain what the EGR line/valve is, and what it does? I just installed long tube headers and new mufflers on my 93 F-150 with the 5.0 and auto. I did not reconnect the EGR line into the new exhaust. The truck runs just fine. All accessories work. What does this thing do? Why do I need it? Can I get rid of it and all other smog stuff? (and I don't mean technically/legally can I get rid of it, I mean will the truck run without it?) Thanks in advance!! Preston
EGR valve re-introduces exhaust gases into the fuel air mixture. Improves mileage,reduces temps and NOX pollutants. It will run without it but would run better with it assuming it works correctly. Removing it depends on your local emission laws and inspections. If you have to do any sort of exhaust gas test for licensing it will fail for sure without it.
Its removed by hotrodders because, we dont want exhaust gas polluting the big fat fuel air charge we managed to tune into our engines with all the performance stuff we have done to em. They(EGR valves) got a bad rap in the late 70's. Poorly maintained engines tended to have EGR problems which affected drivability. That and the component itself was deemed expensive to repair since it was considered some foul form of black magic.
Well, here's my thing with it. In doing the headers, we cracked something plastic on the back side of the engine. It's some type of plastic housing that is in line with the EGR system. Doesn't affect anything apparently, just makes noise. So I thing my we'll focus on removing EGR stuff today... I just don't llike the idea of putting hot exhaust gas into my intake charge...Seems like it isn't good for performance... Thanks Guys!
With your computer tuned for using the EGR your going to run into lean conditions under heavy load. Maybe the computer can adjust injector timing to fix it, maybe not. Personally I would just fix it, OR get the computer tuned without the egr used and then remove it.
The plastic stuff you're referring to, depending on where it is, is the secondary air supply valves and/or the control solenoids. Diverter valve is in the center above the trans bellhousing and the bypass is somewhere up front closer to the air pump. There is a check valve in each tube supplying the valves to prevent exhaust from flowing back into the system. You'll have to put a cap (preferably welded) over the check valve connections to the y-pipe (depending on what is still there after you replaced the exhaust). The EGR on the 5.0l is fed by a metal tube from the middle of the lower intake under the upper plenum. Sounds like the AIR system by what your are describing. The purpose of the secondary air system is to provide fresh air to the exhaust system up stream of the catalysts to burn off the rich mixture required for smooth operation on cold start and to light off the catalysts for faster cat warm up, and to divert air downstream of the reduction catalyst but before the oxidation catalyst during lean cruise driving to clean up the exhaust. The solenoids near the coil on the drivers side rear of the engine control EGR(exhaust gas recirculation), TAB(thermactor air bypass) and TAD(thermactor air diverter). If emissions isn't a concern and it's not illegal where you are, those systems may not have any effect on engine operation other than maybe a little spark knock. (timing is advanced during EGR application due to the diluted air/fuel mixture) TAB/TAD are somewhat invisible and may only be noticed during a EEC self test when they set codes. Fouling of the catalyst and higher emissions are likely as well. The EGR system is off during wide open throttle. hope this helps.
Thank y'all for the information! Today we disconnected what I've always heard referred to as the smog pump. Facing the engine, it's on the bottem left side of the engine. I had another Ford Truck that this was disconnected on, and it ran fine. So we unhooked it. So far so good. The piece that is broken is right behind the intake. It's a metal housing with a nipple sticking up with a hose clamp holding a rubber hose on it. The strange thing is that whatever it is, the air is being blown out of it, not sucked in. And the air is warm/hot, like exhaust gas. I'm wondering if I can block that off? I don't know what the implications of that would be. I know that on my Maverick, exhaust leaves the engine through the headers and nowhere else. I can't see why this 302 would be that much different? Am I wrong? I promise I'll stop asking questions soon! Thanks y'all!
Definitely the diverter valve. The check valve may be broken internally allowing exhaust out. The "smog pump" is the air pump I referred to in my earlier post. If you took the pump off, all of the hoses attached aren't doing anything anymore. The crossover pipe that goes from one cyl head to the other with that valve attached can be removed and plugs installed in the holes. If you don't install the plugs, you'll have a large exhaust leak. The holes connect to the "emissions bump" in the exhaust port in the cylinder heads. That is where the air is introduced upstream for catalyst light off. If your Ford dealer can't find the plugs for you, PM me and I'll see if I can track down the part #. (they install on the front of the cylinder heads where the brackets mount so the heads are reversible)
Thank you very much! I'll check with Ford tomorrow when I go pick up my new dipstick tube. I really, really appreciate the information. I'm really ignorant when it comes to all of the emmisions and Computer controlled aspects of these engines. Thanks so much!
Federal law makes it a crime to remove any factory installed emission devices. I doubt Ford will help you with information unless this is for an "off-road" car.
Paul does raise a valid point. To stay legal "off road" is the operative term when discussing these things. It is illegal to just remove it. Reputable shops usually won't do it because they can get fined. Those rules are geared more toward businesses than individuals, but who knows when big brother is watching. Most of the components you're talking about, especially on older vehicles, are no longer available so you would have to replace them with something that performs the same end result. (although some states, California for sure, require all of the equipment to be intact and operative verified by a visual inspection) The good thing is, if you want to make it pass a tailpipe test, if the engine is otherwise relatively stock, the modern 3 way catalyst for sale through exhaust sites and shops are much more efficient at cleaning the exhaust up now than they used to be so you can install either a large one or 2 smaller cats later, reduce your ignition timing and it could pass without the other equipment. Just go oversize with the catalytic converters if this is what you have to do. All of the above really depends on your states' requirements. For the record, this was the disclaimer. "I know nuting!!"
We don't have any emissions checks or anything here in Louisiana. This is my Farm Truck and my High School Ag Class's Project vehicle. We're just trying to see what we can do to the truck with bolt-ons. And by undoing a few of the unnecessarys... Thanks y'all!
