2G Don"t disable the EGR valve

[InterceptorF]

I have been fighting my GST for a while now with drivability issues. I decided to put the EGR circiut back on the car and VOLA! it fixed all my idle issues, drivabilty came back and now I am confident in the car making it home. I don't know why I ever took it off but I am glad I decided to put it back on!!

 

[92AWDHX40]

Maybe you had a leak there.

 

[2GbTalonGuy]

What kind of drivability issues were you having?

I agree with iugrad, you probably had a leak there or one of the vac lines weren't buttoned up correctly.

 

[johnmel]

Fact is fact if you want to keep you car for a long time keep the egr if you want brunt pistons hot engine and to replace all that stuff with in a yr or two or if your lucky three then take it off

 

[BogusSVO]

Fact is fact if you want to keep you car for a long time keep the egr if you want brunt pistons hot engine and to replace all that stuff with in a yr or two or if your lucky three then take it off

Well... please explain your fact, and links or books you got your info from.

 

[Aphix]

Burnt pistons??

Your EGR has multiple T fittings that tie it into the EVAP system as well, so it is very possible there was a vacuum line left off somewhere that affected both fuel pressure from creating a positive pressure in your gas tank, and possibly let excess air in. If you had air rushing out when you opened your gas cap, your PCV wasn't functioning.

Secondly, an EGR delete has very little to gain beneficially aside from avoiding carbon buildup from a decade or more of running. It runs on vacuum, therefore every time you boost, your EGR valve is both closed and being pressed closed, not affecting performance. While you're cruising it's helping to increase your fuel economy.

I'd recommend going through your vacuum lines, because they are horribly problematic because of people messing with them and also being worn out over time. Zip tie all of them to the nipples they goto, the stretched out ends will cause multiple leaks under boost.

 

[talonalex92]

The only way an EGR valve is going to give driveability issues is if it is stuck open. Im talking the valve itself. Leaks are a definate possibility, among other things but aside from a CEL your car isnt going to run any different without it properly blocked off. Something else was the cause, and you just happened to fix it.

 

[johnmel]

Well... please explain your fact, and links or books you got your info from.

Got this info from here http://www.enginebuildermag.com/Art..._the_causes_of_burned_or_scuffed_pistons.aspx
Question: My engine burned a piston. What does that mean and why did it happen?

Answer: It means the piston failed due to excessive heat in the combustion chamber. A burned piston will typically have a melted appearance, or a hole burned completely through the top of the piston. Aluminum can only withstand so much heat, and when it gets too hot, it melts. The underlying cause is usually detonation and/or pre-ignition.

Detonation occurs when the temperature and pressure inside a cylinder exceed the fuel's octane rating. Instead of igniting when the spark plug fires, the air/fuel ignites spontaneously much like a diesel engine. This creates multiple flame fronts within the combustion chamber that collide and hammer the top of the piston, producing a metallic knocking noise called "spark knock."

Common causes of detonation include a buildup of carbon deposits in the combustion chamber and on the top of the piston that increase compression, no EGR (exhaust gas recirculation), overadvanced ignition timing, a bad knock sensor, a lean fuel mixture, low quality gasoline that does not meet minimum octane requirements, or any cooling problems that causes the engine to run hotter than normal (coolant leak, low coolant level, bad water pump, stuck thermostat, restricted radiator, defective cooling fan, even exhaust restrictions that back up heat into the engine.

 

[GSLENK]

, no EGR (exhaust gas recirculation),

It was my impression that the EGR doesnt operate under the conditions that would typically promote knock (timing advance, leanness) those usually occur in the powerband under load (boost). you shoud be a little clearer in your arguement.

you cite carbon buildup, and then cite no egr, those are seemingly 2 opposing factors... you should pick a side to build a better argument. (not saying your wrong, just unclear)

 

[romeen]

Fact is fact if you want to keep you car for a long time keep the egr if you want brunt pistons hot engine and to replace all that stuff with in a yr or two or if your lucky three then take it off

Do you know the purpose of the EGR and how it works?

Question: My engine burned a piston. What does that mean and why did it happen?

Answer: It means the piston failed due to excessive heat in the combustion chamber. A burned piston will typically have a melted appearance, or a hole burned completely through the top of the piston. Aluminum can only withstand so much heat, and when it gets too hot, it melts. The underlying cause is usually detonation and/or pre-ignition.

Detonation occurs when the temperature and pressure inside a cylinder exceed the fuel's octane rating. Instead of igniting when the spark plug fires, the air/fuel ignites spontaneously much like a diesel engine. This creates multiple flame fronts within the combustion chamber that collide and hammer the top of the piston, producing a metallic knocking noise called "spark knock."

Common causes of detonation include a buildup of carbon deposits in the combustion chamber and on the top of the piston that increase compression, no EGR (exhaust gas recirculation), overadvanced ignition timing, a bad knock sensor, a lean fuel mixture, low quality gasoline that does not meet minimum octane requirements, or any cooling problems that causes the engine to run hotter than normal (coolant leak, low coolant level, bad water pump, stuck thermostat, restricted radiator, defective cooling fan, even exhaust restrictions that back up heat into the engine.

BogusSVO has more than proven himself and is widely respected on the forums for his knowledge and experience working on all types of motors. To respond in a condescending way makes you look foolish. If you have any type of personal experience supporting the claim that an EGR delete will directly lead to a burned piston then please share.

 

[1990AWD]

Got this info from here http://www.enginebuildermag.com/Art..._the_causes_of_burned_or_scuffed_pistons.aspx
Question: My engine burned a piston. What does that mean and why did it happen?

Answer: It means the piston failed due to excessive heat in the combustion chamber. A burned piston will typically have a melted appearance, or a hole burned completely through the top of the piston. Aluminum can only withstand so much heat, and when it gets too hot, it melts. The underlying cause is usually detonation and/or pre-ignition.

Detonation occurs when the temperature and pressure inside a cylinder exceed the fuel's octane rating. Instead of igniting when the spark plug fires, the air/fuel ignites spontaneously much like a diesel engine. This creates multiple flame fronts within the combustion chamber that collide and hammer the top of the piston, producing a metallic knocking noise called "spark knock."

Common causes of detonation include a buildup of carbon deposits in the combustion chamber and on the top of the piston that increase compression, no EGR (exhaust gas recirculation), overadvanced ignition timing, a bad knock sensor, a lean fuel mixture, low quality gasoline that does not meet minimum octane requirements, or any cooling problems that causes the engine to run hotter than normal (coolant leak, low coolant level, bad water pump, stuck thermostat, restricted radiator, defective cooling fan, even exhaust restrictions that back up heat into the engine.

There are many causes of why you melted a piston, including the EGR, but the EGR probably isn't the cause. Not to mention almost everyone on this site runs an EGR delete with no ill effects.

 

[johnmel]

Do you know the purpose of the EGR and how it works?




BogusSVO has more than proven himself and is widely respected on the forums for his knowledge and experience working on all types of motors. To respond in a condescending way makes you look foolish. If you have any type of personal experience supporting the claim that an EGR delete will directly lead to a burned piston then please share.

Yes I know what a egr does and what its for

Also in know way shape or form was I being a dick or "condescending" yes I know people you have done a egr delete and have messed there pistons up from it my buddy is rebuilding his ls1 for this exact reason I was just simply showing on a site that a egr delete can cause this and I put the link so of anyone wanted to read it they can. So I don't see how I'm being condescending

 

[Colt4G63 also]

EGR is designed to reduce combustion tempratures, but for the purpose of reducing NOX (a toxic polutant). I have never heard of non EGR engines all failing due to melted pistons, and there were plenty of cars built without EGR valves that don't seem to have those failures every two or three years.

EGR valves do not operate under WOT conditions.

PS. I have been running EGR blockoff for several years now, and after reading this I am going to run out and buy water/meth injection if it isn't already too late.

 

[TJCTalon]

Hmmmm...

Deleted my EGR and all related emission equipment CORRECTLY and I have no drivability issues, and in fact Im sure I fixed multiple boost leaks when I did this. Car has never ran better.


You cannot blame a melted piston on not having an EGR. EGR is an emissions equipment, used to lower oxides of nitrogen. Even before there were EGR's and emission standards there were melted pistons. Whats to blame then?

EGR is designed to reduce combustion tempratures, but for the purpose of reducing NOX (a toxic polutant). I have never heard of non EGR engines all failing due to melted pistons, and there were plenty of cars built without EGR valves that don't seem to have those failures every two or three years.

EGR valves do not operate under WOT conditions.

PS. I have been running EGR blockoff for several years now, and after reading this I am going to run out and buy water/meth injection if it isn't already too late.

Wait are you serious? Your going to run and get a water/meth injection kit now?

 

[Aphix]

I just hopped on ecuflash and looked at all the parameters that the EGR valve is tuned for. They include egr vs. load, egr normalization vs. coolant temp, and egr vs rpm. The egr is 55% normalized at 32 degrees celsius, and 100% normalized by 82* celcius. If percent normalization is a measure of increased EGR duty, then it would imply that it does indeed cool the engine combustion temperature.

However this is only true when the throttle plate is less than something like 1/3 to 2/3 closed, otherwise vacuum wouldn't be high enough to open the EGR. And the 4g63t uses a knock sensor regardless.

 

[johnmel]

1990awd... egr actually cools the engine

 

[talonalex92]

EGR is designed to reduce combustion tempratures, but for the purpose of reducing NOX (a toxic polutant). I have never heard of non EGR engines all failing due to melted pistons, and there were plenty of cars built without EGR valves that don't seem to have those failures every two or three years.

EGR valves do not operate under WOT conditions.
PS. I have been running EGR blockoff for several years now, and after reading this I am going to run out and buy water/meth injection if it isn't already too late.

DING DING! Egr valves operate under normal operating temp, during steady state cruising.

 

[Colt4G63 also]

Wait are you serious? Your going to run and get a water/meth injection kit now?

No I was kidding.

However I would like one of those CMGS progressive systems with the flow detector. That would be sweet. I could replace that cheap rattling boost gauge once and for all. I hate listening to that thing when I'm idling.

 

[romeen]

Yes I know what a egr does and what its for

Also in know way shape or form was I being a dick or "condescending" yes I know people you have done a egr delete and have messed there pistons up from it my buddy is rebuilding his ls1 for this exact reason I was just simply showing on a site that a egr delete can cause this and I put the link so of anyone wanted to read it they can. So I don't see how I'm being condescending

I didn't accuse you of being a dick. But the info you posted, although well written, is very basic and obviously aimed at people who are just learning about how motors work. BogusSVO has proven that his knowledge is way beyond the level of that article. Hence, the reason that it comes off as condescending.

The problem is when you take the info that having no EGR can be a potential cause of detonation (debatable) and, from that, draw the conclusion that deleting the EGR WILL cause "brunt pistons hot engine and to replace all that stuff with in a yr or two or if your lucky three" and claim that this is a "fact."

No offense, but it reminds me of people who read something on WebMD and then think that they are now qualified to diagnose people.


BTW, has anyone seen all of the crap that the EGR recirculates back into the intake? Maybe I'm wrong but it seems like the EGR would increase carbon buildup.

 

[johnmel]

1990awd actually the egr cools down your engine. And I'm not arguing with you guys my egr is stuck closed and my car rubs runs better now I'm just simply saying that doing a egr delete can cause things to go wrong

 

[Aphix]

It does look to increase its duty cycle when the engine gets hotter according to ECUflash. There might be some cases where an engine's timing is tuned to be that reliant upon EGR, but regardless our engine runs a knock sensor and would adjust timing.

 

[johnmel]

I didn't accuse you of being a dick. But the info you posted, although well written, is very basic and obviously aimed at people who are just learning about how motors work. BogusSVO has proven that his knowledge is way beyond the level of that article. Hence, the reason that it comes off as condescending.

The problem is when you take the info that having no EGR can be a potential cause of detonation (debatable) and, from that, draw the conclusion that deleting the EGR WILL cause "brunt pistons hot engine and to replace all that stuff with in a yr or two or if your lucky three" and claim that this is a "fact."

No offense, but it reminds me of people who read something on WebMD and then think that they are now qualified to diagnose people.


BTW, has anyone seen all of the crap that the EGR recirculates back into the intake? Maybe I'm wrong but it seems like the EGR would increase carbon buildup.

Look man I'm not saying I know everything and your right that they do put in alot crap back unto the car

 

[Junfan]

I experienced that last fall when I did the block off plate. I discovered the plate was slightly warped and not sealing well so I decided a great solution was to sandwich block off plate between the manifold and EGR. It gave it enough meat to tight down good and flatten the plate. It was my cheap easy solution.

 

[1997 eclipse gs-t]

but mines runs hot slowy at stop lights unless i pressed the gas to get the rpms up to 3000 rpm then the temp goes back down to normal.i know it has something to do with the egr valve because the first time i plugged the vacume lines back up to it idled fine and i drove the car all day and it never ran hot at all. but the next day it went back to driving the same way,rough idle and overheating. also i found out my bov is leaking badley could that make the car run hot.

 

[bryanwheat]

but mines runs hot slowy at stop lights unless i pressed the gas to get the rpms up to 3000 rpm then the temp goes back down to normal.i know it has something to do with the egr valve because the first time i plugged the vacume lines back up to it idled fine and i drove the car all day and it never ran hot at all. but the next day it went back to driving the same way,rough idle and overheating. also i found out my bov is leaking badley could that make the car run hot.

It sounds like you are low on coolant if it is heating until you give it gas. I've removed the egr on every dsm that i've ever owned (about 15 of them) and never had an issue.