Ok so I now have a hand me down 1973 Chevelle Laguna 4door.Green on green with a blue fender.
She's quite the looker graemlins/waving.gif

Anyway this thing is all stock with a 2barrel carb and an EGR valve.

What is the best way to remove the EGR valve from the system?

Should I simply remove the lines from the carb and plug them.
Will leaving the valve in place but not working cause any problems?

Or should I remove the EGR valve from the manifold and plug the hole?

Will this screw up the carbs metering at all?

The reason I ask is that I reciently adjusted the idle mixture screws to acheive the best idle.It them started surging at light throttle freeway speeds.
I had to richen the carb about 3/4 turn.

I also noticed on the engine sticker,located on the radiator support states 900rpm lean idle drop.

What the heck is that???

I am very familiar with performance stuff, but this stocker carb and EGR...I just don't know.

Well, I definitly ain't an emissions guy but here are a couple of simple thing I know about EGR ;)
Engines with EGR are designed to run lean.
The EGR is sort of a "bandaid" for this. They let exhaust gas into the intake tract which dilutes the mixture & cools the combustion process because exhaust gas is inert & doesn't burn controlling detonation among other things.
While this dilutation may sound like a bad thing & performance wise probably isn't the best plan Detroit came up with it helps with emissions.
When you disable it without changing the carb or carb metering because of the lean metering it will usually cause detonation which will not make your engine happy :D

Fix the EGR instead of disabling it. Wolfplace is right, the car is gonna ping like crazy if you unhook the hose.

Lean drop involves setting the idle mix using a special propane enrichment tool. You could get close by adjusting for best lean idle, then turn the screws 1/4 turn leaner, or just enough so the idle vacuum drops about 1/2" to 1" Not enough to make a real difference in idle quality, but makes a HUGE difference in pollution.

Darn.
It looks like I need to locate a stocker non EGR carb and manifold for it.
That should be fun.

I don't want to get into the the perfornance realm with it.

I'm going to have to disagree with some of the above comments. The reason that your engine detonates when removing the EGR function is because most EGR equipped engines run a distributor with more vacuum advance for the cruise/light load conditions under which the EGR will be in operation.

EGR has NO affect on WOT performance. You will gain NOTHING performance wise by disconnecting it. Your best choice is to fix the valve.

Your second best choice is to get a non egr distributor, a decent 4bbl manifold without EGR and a 4bbl.

Mike

Originally posted by Unclepennybags:
I'm going to have to disagree with some of the above comments. The reason that your engine detonates when removing the EGR function is because most EGR equipped engines run a distributor with more vacuum advance for the cruise/light load conditions under which the EGR will be in operation.

EGR has NO affect on WOT performance. You will gain NOTHING performance wise by disconnecting it. Your best choice is to fix the valve.

Your second best choice is to get a non egr distributor, a decent 4bbl manifold without EGR and a 4bbl.

Mike Mike,
While I agree with your comments about the distributor etc., I am courious about what are you dissagreeing with?
No one said to dissconnect it or that their was a performance improvement in disconnecting it.
I believe it was stated not to disconnect
it :confused:

Originally posted by Wolfplace:
Mike,
While I agree with your comments about the distributor etc., I am courious about what are you dissagreeing with?
No one said to dissconnect it or that their was a performance improvement in disconnecting it.
I believe it was stated not to disconnect
it :confused: Mike,

I was disagreeing with the notion that engines equipped with EGR are designed to run lean. As you pointed out, EGR is an inert gas. Therefore, the calibration would not need to be richer (or leaner for that matter) just because an EGR valve is installed.

You are correct in pointing out that none of the people replying suggested removing it. My comments about not removing it where intended to encourage the original poster to rethink removing the EGR valve from the system. I was assuming from the post topic, and him asking about how to remove the EGR valve from the system, that he was planning on removing the EGR valve. ;)

Mike

Well I did a little work on it and found a couple of things.

The vacuum advance canister was bad so I replaced it.
The carb leaks a little.I think it is making the engine lag a little when I give it light throttle.
I will probably rebuild it next week.

I found that someone had plugged the EGR valve hose and plugged it back in to make it look operable, when in fact it was not.

I removed the plug and reconnected it.

It still surges.

Is there something wrong with the EGR?

How can I tell?

thrasher, you can tell on some of them if they're operational by watching the diaphram or rest the tip of a screwdriver on it while you connect and disconnect the vacuum hose to see if it moves. The exhaust port in the intake manifold for the EGR (where it mounts) sometimes gets clogged with carbon. An old shadetree fix is to temporarily remove the EGR valve and plug the vacuum line. Start the engine while someone plugs the intake port for the EGR. Leave the exhaust port alone and rev the engine. This will blow carbon out of the exhaust port. It makes some noise and a little mess but works.

Originally posted by thrasher:

Is there something wrong with the EGR?

How can I tell? Thrasher,

There are a couple of quick and dirty checks to make sure the valve is working. First, verify that the EGR valve holds vacuum. Don't need to start the car to do this. You can do this with a vacuum pump, or good old fashioned lung power.

If it holds vacuum, apply manifold vacuum to the EGR valve while the engine is idling. The engine should begin to run rough. If it does, then you know that the valve and the rest of the system is working correctly. Release the vacuum to the EGR valve, the idle should return to normal.

When you are done testing, hook the EGR back up to the correct vacuum source.

Mike