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View Full Version : Chevy 4.3 EGR valve



kendals85
08-31-2009, 12:46 AM
Hey wats up?? soo I have a 85 Monte with a 4.3 V6 FI..I want to clean the engine up alil.. If i take off the egr valve will it effect it at all?? None of the smog sh*t is hooked up.. and also theres wires and a connector on the canister..wats is that for.. can i unhook it?? will it effect anything?? wat else can i get rid of?? And also I know a 4.3 is like a V8 but will stuff fit on the 4.3 V6? like water pump, alt, brackets,water neck,timing chain cover? stuff like that?? Thanks

UR50SLO
08-31-2009, 05:08 PM
Welcome Kendal.

You can remove the EGR. (Dependant on smog testing in your area)

You'll need to make a block off plate there so air is not sucked into the intake and exhaust is not blown out of the other hole.

That is the canister purge.(connector) it's a output only so if you unhook it... it will not cause a SES light. Might notice some raw fuel smell if you totally unhook the canister from the line that go's to the fuel tank.

If it was equiped with "AIR" pump you can remove that (Not A/C) and all lines to manifolds ect.

There are several differences in the 4.3L and the Small Block.

They share the same bore and stroke.
The crank journal on the 4.3L is larger (Big rod end)
Push rods/rockers/lifters are same. T-Chain is different

What all are you trying to do with the car?

That's a start.. what other info are you looking for?
~Scott

kendals85
08-31-2009, 06:57 PM
the air pump is already off, i took it off when i got the car, it wasnt hooked up when i got it, thers a connector with a vac line (goin to that canister) right by the egr valve wats that?? can i take that off? will it effect anything?? I want to keep it a V6 4.3 FI just want to clean it up abit, i want to take anything i can off of it (anything i dont really need)

UR50SLO
09-02-2009, 05:04 AM
That should be the Evap line. Take a pic and post it if you could.. that way I can be sure.
Thanks!
Scott~

OneSlowL36
09-02-2009, 05:50 PM
I would keep the EGR valve and clean it up. It'll keep your intake temperatures down, you'll pollute less, and you'll keep some mileage. And they don't affect performance since they close at WOT. If you removed the smog pump then remove the cat too. The pump makes the cat more effective and keeps it oxidized. They usually fail without it on older cars/trucks. Just somethin to think about. :)

UR50SLO
09-02-2009, 07:20 PM
How exactly is putting hot exhaust gas into the intake going to "lower" intake temps?

The only reason it lowers combustion temps is because exhaust can't burn and there for

would lower combustion chamber temps. It's a dirty and terrible way to try and

curb emmissions.

Cat. converters are just a way to burn off the fuel the engine does not. It's sad that

our current engine designs are so poor that we need to add a converter to burn off the

excess fuel that the engine design can't .. but that's what we have.

Scott~

kendals85
09-02-2009, 09:28 PM
i dont have a cat converter on my car..soo.. u guys r sayen i should keep the egr valve?? But would it mess with the comp, or engine; idle anything??and wat about the egr solenoid?? wat would happen it i took this off?? keep in mind this is a 85 4.3 FI. I have all the smog stuff off and its not messen with the comp, or engine that i know of.. Thanks.. any tips on how to make a 4.3 look better..

OneSlowL36
09-02-2009, 10:23 PM
How exactly is putting hot exhaust gas into the intake going to "lower" intake temps?
The only reason it lowers combustion temps is because exhaust can't burn and there for would lower combustion chamber temps. It's a dirty and terrible way to try and curb emissions.
Cat. converters are just a way to burn off the fuel the engine does not. It's sad that our current engine designs are so poor that we need to add a converter to burn off the excess fuel that the engine design can't .. but that's what we have.
Scott~

Man I hate to say it but you're misinformed. The EGR lets burnt gasses back in, when that happens you are displacing some of the incoming air and fuel to the cylinder. Less oxygen coming in = less heat made. The added benefit is by displacing that area, you use less air and fuel. Hence the mileage. The only emissions it controls is NOx, which is created when combustion temps go over 2500 degrees.

Catalytic converters convert CO and HCs into CO2, 02, and H20. If its a 3 way cat (which i believe most have been for a while) then they control NOx just as the EGR does.

Sorry to take this off track.


i dont have a cat converter on my car..soo.. u guys r sayen i should keep the egr valve?? But would it mess with the comp, or engine; idle anything??and wat about the egr solenoid?? wat would happen it i took this off?? keep in mind this is a 85 4.3 FI. I have all the smog stuff off and its not messen with the comp, or engine that i know of.. Thanks.. any tips on how to make a 4.3 look better..

You can ditch the EGR and be fine, but there really is no reason to.. it doesn't hinder performance or repairs - but its your truck if you think its gawdy then by all means remove it, just block off the intake and exhaust ports. You MAY have an SES light depending on if your computer has a signal for it, but it won't have an effect on driveability.

UR50SLO
09-03-2009, 06:04 AM
Your on the right track but you said that it lowers "Intake" Temps... Putting hot exhaust gas into the intake can not lower the incoming air temperature.

That why I said Combustion chamber temps since there is less Oxygen to burn thus lowering the heat in the chamber as there is less oxygen to burn with the incoming air being diluted with burnt up exhaust.

It's my openion that it causes more problems than it helps from all the stuff I've ever worked on and tuned.
But everyone does things differently. That's ok too. ;)

OneSlowL36
09-03-2009, 09:43 PM
Your on the right track but you said that it lowers "Intake" Temps...


Why you are absolutely right I didn't realize that :dammit:

UR50SLO
09-05-2009, 06:56 AM
I think your mind was thinking the right thing just the keyboard was typing the wrong thing...

Ok.. that totally sounded like my wife.. since every"Thing" is a Thing.. or somthing like that... LOL.
:)