Mine throws a code on the highway, but never around town. I was wondering if it could be what is slowing down my 1/4 mile times. You know the whoile exhaust gas in combustion chamber thing

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1992 Formula 350
-SLP 1 3/4 Headers
-Ported Plenum, Polished w/ polished runners
-Airfoil and other small bolt on mods

 

i cant say that it does for sure, but i'm pretty certain that it does. On my avenger a few months back it suddenly started to run like ****... got horrible gas mileage, wouldn't start up, etc... well it turned out to be the EGR valve...so i think it's safe to say that it can effect your 1/4 times

 

what exactly does EGR do? I know it means Exhaust Gas Recirculation, but how is sending exhaust into your chambers good at all? Also, do you hear your EGR valves at 2000 RPMs, or is that something else? Any way to check if the valves are sticking? Sorry this does't help your question, but hopefully it'll help answer some of mine.

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1984 Z-28, 305HO 4bbl, t-tops, K&N, Flowmaster 80 Series with 3" tips. Planning a massive modfest. It's gonna be one gangsta of a street demon.

 

Adam,

Unless the EGR is sticking open and leaking vacuum, it shouldn't affect the ¼ mile performance at all. A non-functioning but sealed EGR is just like a fully functional EGR in WOT operation - it doesn't open at all.

If your's is leaking, however, your performance will suffer greatly. There's nothing like a major vacuum leak to slow you down.

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Later,
Vader
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If you want to beat the World, it might reach up and pull you down...
Adobe Acrobat Reader

 

exhaust in the combustion chamber helps to lean it down...

 

Would the EGR leaking cause problems with vacuum when I shift from neutral to drive, etc? Sometimes the idle will drop very low and the motor will die.

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1992 Formula 350
-SLP 1 3/4 Headers
-Ported Plenum, Polished w/ polished runners
-Airfoil and other small bolt on mods

 

Also how can I tell which way it is stuck? Its hard to check for a leak on something directly under the intake. Any tricks? Ive been told the carb cleaner method, maybe I'll give that a shot.

 

Ok I checked for vacuum leaks and the thing is sealed up tight. However I think my sensor thing is messed up, in a few minutes I am gonna pull it out and take a look at it.

Can anyone tell me on the EGR sensor which vacuum line goes where- there are two coming from it, one to EGR and one to TB. I need to know if the TB is top and EGR is bottom or vice versa.

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1992 Formula 350
-SLP 1 3/4 Headers
-Ported Plenum, Polished w/ polished runners
-Airfoil and other small bolt on mods

 

Yes and no. The system does route inert exhaust gas into the cumbustion chamber, but the goal of the system is to cool the overall cumbustion process by introducing inert exhaust gasses that will not cumbust. So EGR does 'lean' it out, but what it is leaning out, is the cumbustible gas intake of the engine. Less cumbustible gasses in the chamber = less cumbusting. By not cumbusting in the chamber, the inert exhaust gasses lower the overall burn of the air fuel mixture which essentially cools the cumbustion temperatures down and cools all of the surrounding parts down. The exact task of the EGR system, is to lower the chances for detonation to take place. Detonation (otherwise known as Ping or Pre-ignition - they all mean the same thing) is what happens when there is another source of ignition for the air fuel mixture present other than the spark plug. So by lowering the overall temperature of the cumbustion chamber and it's components, you lessen the chances of there being a place for detonation to take place.

So by knowing what the EGR system does, you can see that it is actually useful, if you don't have your spark advance settings set 100% correctly. If you have your spark dialed in 100% correctly, you really have no need to worry about detonation and EGR is not needed or useful.

And, as a function of how the EGR system works, it does in fact lower the power output of the engine - WHEN IT IS ACTIVATED! When the EGR system is idle, it doesn't cost you any power (well, almost none. They plumbing of the EGR system in the intake manifold of our engines does heat up the air coming into the engine since it routes hot exhaust through the same piece of aluminum that the incoming air passes through, and rather close to those passages for the incoming air. But this is really a nominal and minute power loss).

And GM, as well as pretty much all other car manufacturers out there, have the EGR system go idle (stay closed) at WOT to allow the engine to make as much power as it possibly can.

Hope that helps explain it a bit.

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1987 GTA L98 MD8
355, TFS Heads, LT4 Hot Cam
My GTA

The Minnesota F-body Club