EGR Questions

[007]

What are some symptoms of a bad or failing EGR valve on these Jeeps?

 

[Torxhead]

If it doesn't work then the combustion chamber temps would get hotter as its job is to cool it down. If it lets to much exhaust into the combustion chamber it would stall the engine. I would suggest googling it to learn more of its operation, you could also just replace it. There could be a problem with the sensor that controls it also.

 

[007]

If it doesn't work then the combustion chamber temps would get hotter as its job is to cool it down. If it lets to much exhaust into the combustion chamber it would stall the engine. I would suggest googling it to learn more of its operation, you could also just replace it. There could be a problem with the sensor that controls it also.

Well I've been doing just that and I'm more confused than ever. I mean, i know what it does, just not sure how to tell if I have a good one.

I don't mind having one as long as it works. There's a group of people that say block it off and forget about it, another group says clean or replace every 15k.

NO idea how old mine is, hate to replace something that may work but if I don't "need" it, then why have it...blah blah blah.

Just trying to figure out how one would know if theirs was "bad"...

 

[hdgapeach]

One way to troubleshoot a possible EGR sticking is to drive it on level roadway at a constant speed (basically a no-load cruise). If you experience skipping, stop and pull the vaccum hose and plug it, then repeat the drive. If the repeat cruise has no skipping, your EGR is probably sticking and either needs cleaning or replacing (if you intend on having it functional).

If you're in a no smog test location, pulling the vaccum hose and plugging it won't cause any issues - so long as the EGR valve is CLOSED. You can use a screwdriver to help if it's stuck in a partially open position. If you have carbon buildup on it, you'd be better off to pull it and clean the debris off of it, re-install, THEN plug the hose.

Personally, I pull all of mine off my old vehicles and block off the port with a homemade plate and block off the vacuum supply. That way I don't have to worry about the thing being stuck in a partially open condition (which will cause the skipping whether the vacuum supply is connected or not).

 

[jdcaples]

Someone once told a friend of mine to start the engine, remove the cap as you would to add engine oil, place a piece of paper over the hole. You should see the paper flex toward the engine like it's being pulled into the hole.

Never tried it myself.

 

[hdgapeach]

Someone once told a friend of mine to start the engine, remove the cap as you would to add engine oil, place a piece of paper over the hole. You should see the paper flex toward the engine like it's being pulled into the hole.

Never tried it myself.

Never tried that one, either. Although, I don't remember having issues with any of the ones I've worked on having idle issues because of the EGR. All I've dealt with showed symptoms while cruising at highway speeds.

You can check the function of the EGR valve with a vacuum brake bleeder tool. You'll be able to actuate the valve when pulling a vacuum. If the vacuum leaks down, you either have a bad diaphram (EGR) or bad seal with the tool and hose. At least, you'd be able to see how the valve works. You'll also be able to see if the valve opens smooth or jumps as it opens (a sign of carbon buildup).

 

[mtnwhlr]

You can check the function of the EGR valve with a vacuum brake bleeder tool. You'll be able to actuate the valve when pulling a vacuum. If the vacuum leaks down, you either have a bad diaphram (EGR) or bad seal with the tool and hose. At least, you'd be able to see how the valve works. You'll also be able to see if the valve opens smooth or jumps as it opens (a sign of carbon buildup).

This is how I have always checked them.

 

[Lumpy Grits]

Do this while the engine run'n, and it should 'stumble' when vacuum is applied.
LG

 

[007]

So if these are so necessary, why do older otherwise identical AMC 304 's etc not have them? What are they doing different?


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[Lumpy Grits]

Two words-"SMOG laws".
LG

 

[007]

I got that. But from a mechanical / performance perspective in a non smog state...are they better or not?


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[mtnwhlr]

I got that. But from a mechanical / performance perspective in a non smog state...are they better or not?


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Not

 

[hdgapeach]

So if these are so necessary, why do older otherwise identical 304's etc not have them? What are they doing different?


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That'd be a good question to ask the EPA.........but don't ask! It might give them the idea to make us retro-fit all our old classics .

Reminds me of the ol' "cash for clunkers" campaign years ago; a feeble attempt to rid the country of the smog producers.

 

[007]

Double post my accident.

 

[hdgapeach]

I got that. But from a mechanical / performance perspective in a non smog state...are they better or not?


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Short answer -No. The EGR equipment was the manufacturers attempt to meet the "new" EPA emissions requirements of that time.

Thanks to the EPA; we no longer have the air cooled VW Beetle, carburetors are extinct on new vehicles, computers control everything to do with a car, etc.

Gotta love the gubment!

 

[007]

So why not just block it off if it's bad?


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[hdgapeach]

So why not just block it off if it's bad?


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The only reason for not blocking it off would be if you reside in a location that requires you to "smog" check your vehicle, and pass the emissions test to renew your registration.

No emissions check in my part of GA (so far). I block off EGR equipment on every old vehicle I own.

 

[mtnwhlr]

It's there to keep your tree huggers happy.

 

[hdgapeach]

It's there to keep your tree huggers happy.

Good one! That's funny

 

[mtnwhlr]

What can I say I grew up in Boulder the home base of the tree hugger movement