what EXACTLY does the egr valve do? my wifes car is a 77 with 250 6cyl. there is a vacuum tube that looks like it should attach to the egr valve but when i connect it the car immediatley stalls and dies. unhook it and plug the open end and the car runs fine. i can see the plunger moving on the valve but i can't find anything in my books that tells me anything about how it works or what its job is. this car was built in canada so it still has the factory thermatic air system on it (for now) that will be the first thing i throw away. any help would be appreciated.
The EGR valve , air/smog pump, and cat. convertor all work as a system if you take one off you might as well take them all off. The egr valve takes exhaust from the exhaust manifold and puts it back into the engin to be reburned. Because of the exhaust in the cylinders the engin can`t burn all the gas some times so they put a cat. converter inthe exhaust that gets very hot to burn the rest of the gas. The cat. converter can`t burn the gas without a little fresh air so the smog pump pumps a small amount of air into the exhaust so the whole system will work .
Jason, Read your post in the other thread. Glad to hear you got your engine fixed. About your wifes car, remove all that power robbing smog garbage. Unless your going for the completely stock look. I can't remember what it was used for. I think it had something to do with recycling some exhaust gas to be burned again?????? P.S. Is'nt it a sin to exceed the speed limit on the way to church?
No, its only wrong to speed on the way home frome church because you will learn in church to "obey the laws of the land" but you didn`t know that untill you got to church .
well, Im not too familiar with the 250 EGR system. but, the EGR needs a control, either a soleniod that controls its vacuum or it being plugged to ported vacuum. supplying vacuum when its not supposed is the problem. Im sure a 250 gurru can help you out on that one. as far as what it does, Exhaust Gas Recirculation (EGR) supplies exhaust gas to the incoming air/fuel charge during part throttle. this leans out your air/fuel mixture which does two things: it slows down the combustion process and it also cools down the combustion temperatures. the egr system helps control spark knock (pre-detonation) and keeps your oxides of nitrogen (caused by high exhaust temps) where they need to be to conform to emmision regulations. if you do without it, you might have to adjust for it with your timing (that is IF you are getting spark knock). and as far as the NOx (oxides of nitrogen), I wouldnt worry too much about those... double check me guys, but that should be accurate, its been awhile since my ASE Master days... hope this helps
I took ALL of my EGR, charcoal canister, and anything that attached to it OFF!!! GARBAGE!!! I live in Texas, and anything prior to 1978 is not inspected for smog pollution. I may be a tree-hugger, but when it comes to my ROD, I will kill whatever tree gets a whif of my exhaust! If your laws let you, take it all off, and throw it away! Sounds kinda like strip poker, or skinny dipping, or something like that. I have never engaged in either, but I had fun "doing it" with my Mav. Enjoy the feeling of knowing that you can get away with something that only a small percentage of auto owners can get away with...SMOG! You kinda get to learn to like the smell of it, too!
Your all wrong about the EGR operation! Exhaust gas is reintroduced into the intake air stream during the light load cruise, for the purpose of cooling the combustion temperatures thereby lowering Oxides of Nitrogen emmission. Duriig idle and heavy engine loads, the EGR operation does not function. Exhaust gas cannot burn again, once a product of combustion. It takes up space within the air/fuel and limits combustion temperatures. Back before the cat converters were used, this operation was started. With the avent of converters in the 70s, cats still didnot do any processing of NOX until the mid 80s when 3 way cats were introduced, that process this emmision. Many engines still use this method today right up to 05 Ford mod motors.
The charcoal canister is not part of the EGR system. It collects gas fumes from the tank and sends them down the carb. If you remove this, that remaining metal line/tube will have gas fumes comming out of it and venting into your engine compartment. You should not just plug it because these cars have nonvented gas caps.
Three way means the converter process HC, CO, and NOx. in the byproducts of combustion as required by law. There are other by-products in the gas that are not processed.
With this said, can you just cut the line short. Maybe a few inches outside the gas tank & let it hang. The fumes will just go in the air.
I capped the vent off at the tank. Will this inhibit my fuel flow to the carb by creating a vacuum? If so, can I safely modify the gas cap in some way to make it vent? I want the vent as high in the fuel system as possible, and that would be the cap.
You can just vent it in the back somewhere. This would be better than dumping the fumes in the engine bay. To vent through the gas cap, I would file a few notches in the filler neck where the cap gasket normally seals. Remove it first, of course. This would not be a good place to make sparks.
