Whats up guys?
I was wondering if anyone knows someone who has tried or heard of a way to bypass the EGR valve? (91 5.0L w/ mass air conversion kit)
I pretty much have all the other smog equipment disconnected.
I thought someone way back when said they did it with no probs on a EFI truck.

Thanks,
Jerry D

 

You can take the valve right off and bolt a block off plate on where it used to be but its a bad idea. The EGR valve helps to lower the combustion temps, and helps keep the whole engine cool. If you take it off you would create more pollution (which is not a big deal if you don't have emissions testing) but it could also hurt the engine. You don't lose any horsepower from the EGR because with the lower temperatures you are running more advanced timing. If you take it off you will have to back off the timing so basically you would be right where you started.

Yes i do know people that have taken them off with no problem but i wouldn't do it to mine. However someday i will get around to taking off that #%$^% air pump.

-Jon

 

Thanks for the info.

 

How does the EGR cool combustion temps?

 

Air and fuel are mixed in the cylinder and when they are ignited by the spark plug it burns very hot. When the combustion temps get above 2200 degrees farenheit, the chemical reactions taking place in the cylinder allow NOX (oxides of nitrogen) to form. NOX is considered a pollutant and the government doesn't want any of it coming out of our vehicles so they added the EGR system to our cars. The EGR brings exhaust back into the intake manifold so it gets mixed in with the air and fuel. The exhaust displaces some of the oxygen and fuel in the cylinder which makes the combustion temps a little bit cooler to prevent NOX formation. Kind of like if you add oxygen to a fire it gets hotter but if you were to add carbon monoxide or some other inert gas it would make it cooler because your preventing oxygen from reaching the fuel. You do lose some horsepower with EGR because your not burning as much fuel, but because of the lower combustion temps we can run more advanced timing without worrying about detonation, which gives us back a lot of that lost power.

Thats EGR in a nutshell.

-Jon

 

This guy knows his SH*T.

 

Thanks! That was just the basic theory though. I could explain that when vacuum is applied to EGR port E the strength of the vacuum is dependant on exhaust backpressure in chamber A of the modulator, etc... But that would just be showing off

-Jon

 

Since we have some really knowledable folks here... I wish to pose this question:

I have a 1996 F-150 with a 351C engine. I recently replaced the exhaust from the exit of the cat back. I did this to reduce the back pressure. I had a 3 chamber Flowmaster muffler installed. I am now getting a check engine light for insufficient EGR flow. I am wondering if I meesed with the balance enough to cause this problem. I another previously owned vehicle when I modified the exhaust I had to change the EGR valve out for a different model that didn't require back pressure to operate properly. Could this be the case again? If so how do I locate a part number for an EGR valve that will function with my new exhaust? Thanks in advance for your time ans replies.

Rick

 

First off the cleveland engine was last built in 73-74ish, what you have is a windsor engine (351W). No, the cat back exhaust should not effect the egr valve operation. What I would expect more so is a carboned up egr valve or a bad pfe sensor. Just my $.02

 

if you still want to remove the EGR, go over to www.fordfuelinjection.com and he has a resistor kit that will fool the ECU and keep the CEL from coming on.

 

Mine has been blocked for 10 years in my car with no problems. I disconnected mine in my truck for a couple months now with no problems. I have yet to make a block off plate for the truck.

"Kind of like if you add oxygen to a fire it gets hotter but if you were to add carbon monoxide or some other inert gas it would make it cooler because your preventing oxygen from reaching the fuel."

Yea, but what if the inert gas is extremely hot exhaust gas. Plus, (I guess) it seperates the fuel from oxygen like Ford4ever said. And I thought that's what you want finely mixed in combustion chamber.

Oh, I really don't care, it's not like i'm going to put it back on. Hey, maybe if it ran through some type of air/water intercooler.