EGR valve, is ti needed?

my egr valve leaked so i took it off and plugged the hose, besides the computer reading it not there i there anyting else that could go wrong from ti not being hooked up, it is bolted on jus the vaccum line is plugged by a screw

On my 89 my egr went bad. There was excessive detonation until I replaced it... Hope that helps.

I've blocked them off to check for problems and seems like the vehicle will run fine, if not better than before. Just have that light on all the time though. Those valves are not real expensive, and they last about forever so a junk yard piece off an indentical car might work well too. There are some differences in valves though, might look the same but aren't.

A quick google search produced this:

EGR Theory: EGR serves one purpose and one purpose only.That purpose is to reduce Oxides of Nitrogen (NOx). Undernormal combustion, Nitrogen(N2)Oxygen (O2) in the air and Hydrocarbons (HC) in the fuel combind into water(H2O) Carbon dioxide (CO2) and the Nitrogen remains unchanged. Under very hot combustion temperatures, the Nitrogen reacts with the other two byproducts and forms Nitrogen oxide (NO). After being released into the atmosphere, it picks up another Oxygen and becomes Nitrogen dioxide (NO2). In the presence of sunlight, it combines with other compounds like Hydrocarbons and forms Smog. Since exhaust gas is inert (very stable) it doesn’t burn again. So by being introduced into the combustion chamber, it will lower combustion chamber temps enough so that the Nitrogen doesn’t react with the other compounds and is passed unchanged out the tailpipe thus not contributing to smog.Now,since exhaust gas doesn’t burn, it
doesn’t exactly help with combustion. At higher RPM’s, this really isn’t noticable, but at idle, the reintroduction of exhaust gas will cause a very rough idle and can cause stalling if to much is introduced into the combustion chamber.

wow, i feel dumb now, nice post. I just replaced mine, it was a pain in the butt though. small area to work in.
91 chevy s-10 4.3 l, v6

well , not only does it help the tail pipe emiss...but belive it or not , serves more then just hots purposes....helps the engine warm up faster in the morn by introducing warm air in the engine.....increases mileage but pre heating the mixture....and reduces pinging by actually colling the mixture.....nobody likes EGR cuz its smog related , but it has more benifits then everyont thinks , i guess no one likes it cuz it keeps makin em throw codes ,
:)

I have a 93 with a 4.3 that idles rough at stop lights.

I just bought it so I don't know what has been changed on it or when the last tune up was.

I got a code key from auto zone and all it gives me is a code 12 over and over again.

what is the deal?

The code 12 is called a handshake or something like that, means the computer recognizes the diagnostic mode. Not a trouble code. Your rough idle could be many things, bad spark plug wire, vacuum leak, dirty EGR valve, bad PCV valve or something else. If no other codes are showing it's probably not a computer problem, just an old school worn out/dirty part.

Code 12 is no distributor reference pulse. It is always there when checking codes with the engine off.

You really need a scan tool to check what the computer is seeing while it's running.

back to the egr thread, the egr is benifial as posted above. its not hard to maintain it. as long as the intake is fairly clean, you will not have a problem out of the egr.
running it without the egr will result(eventually) in some inner dammage. propably more costly than just simple maintainance to the egr. just take it off and clean it or replace it.

The code 12 is called a handshake or something like that, means the computer recognizes the diagnostic mode. Not a trouble code. Your rough idle could be many things, bad spark plug wire, vacuum leak, dirty EGR valve, bad PCV valve or something else. If no other codes are showing it's probably not a computer problem, just an old school worn out/dirty part.

COOL. thanks.
and sorry for highjacking this thread. I didn't want to start another one for the same problem.
looks like it is time to tune up the beast.

Guys the EGR valve is not just there for emmissions.

It is there as an anti-detonation system as well to keep cylinder temperatures down and stop pinging which can result in engine damage and poor fuel economy.

Leave the EGR system working properly, it is there for a reason.

I Have A `90 S-10, 2.5l. The Egr Is As About As Useful As Tits On A Bull. Mine Has Been Bypassed For Almost 2 Years, And The Truck Still Runs Better Than It Did With Egr Valve Connected. Not A Necessary Item As Far As Performance Is Concerned.

I Have A `90 S-10, 2.5l. The Egr Is As About As Useful As Tits On A Bull. Mine Has Been Bypassed For Almost 2 Years, And The Truck Still Runs Better Than It Did With Egr Valve Connected. Not A Necessary Item As Far As Performance Is Concerned.

It is needed a lot more than using a capital letter at the start of every single word in your reply.

Without your knowledge, you could be doing detonation damage.

BlazerLT has it dead center. The EGR is an integral part of the combustion process of a modern, computer controlled engine. The cooler combustion temps provided by the EGR system allow for a higher compression ratios (many engines run 9 or 10:1 CR's and this is on the "tractor gas" 87 octane) and, along with the engine computer's control of the timing, maximizes engine power while minimizing detonation. Many modern EGR valves are servo-motor controlled by the ECM and will give a much more accurate "dose" of recirculated exhaust gas than the older, vacuum activated valves.

A high mileage engine may run better without the EGR because it is worn and no longer maintains it's original compression pressure. With the engine compression pressure lost, there is less chance for detonation and the engine can operate without the cooling effects of the EGR.

Keep the thing working.....

mike

amen

I replaced the valve and it runs a ton better.
thanks everyone.

I replaced the valve and it runs a ton better.
thanks everyone.

I respect your smart decision. ;)

I guess I wouldn't say a TON better but it is not as bad it still has a bit of a stumble in it when I sit at a stop light.

You need to do a tuneup then.

Not to re-hijack the thread, but what about restrictor screens, like the one tomco makes? It is supposed to prevent large chunks of carbon from being lodged in the pintle. is this a bad mod? At 8 bucks or so, seems like a good preventative maint. item.

Not to re-hijack the thread, but what about restrictor screens, like the one tomco makes? It is supposed to prevent large chunks of carbon from being lodged in the pintle. is this a bad mod? At 8 bucks or so, seems like a good preventative maint. item.

I wouldn't use it, you want the carbon out of the engine, not trapped in there.