Bypassing Egr Valve


ONITSER
12-15-2004, 12:04 PM
I Have A 93 Blazer Lt, 4.3 Vortec. Is There A Way That I Can Bypass The Egr Valve.

Fractured1
12-15-2004, 02:44 PM
Why would you want too...without it working properly you would end up with a check engine light...if you feel the EGR valve in not working try cleaning it first..There's several post in the forum on "how to"...

BlazerLT
12-15-2004, 04:03 PM
I Have A 93 Blazer Lt, 4.3 Vortec. Is There A Way That I Can Bypass The Egr Valve.

No.

EGR is part of your engine and is there for a reason. Leave it alone.

ricksza
12-17-2004, 06:13 AM
Sure you can bypass the EGR valve. Just buy a block off plate from you local speed shop. While you're at it, buy a fresh motor too because the EGR valve is there to cool the combustion chamber so without it, you will hear a lot of pinging until the motor melts.

BlazerLT
12-17-2004, 03:48 PM
Yip, leave it alone.

tom3
12-17-2004, 06:32 PM
I've bypassed them to diagnose a faulty valve, engine runs fine but the SES light does come on. Gets to be a pain to keep cleaning it but I'd try to leave in operation myself.

BlazerLT
12-17-2004, 08:44 PM
It isn't running fine.

Your knock sensors will be detecting ping and retarding your timing therefore killing your power and fuel economy.

Fireplug
12-17-2004, 09:04 PM
You also forgot that a 93 with the check engine lite on will go into open loop = poor fuel milage

MRogers
12-17-2004, 10:48 PM
Can someone explain why letting hot exhaust gases in is going to cool the combustion chamber? I beleive it is actually just part of the emission system.

metallica21156
12-17-2004, 11:17 PM
if you want it to run cooler then get a EGR gas cooler or make a cutoms one to fit on there. think it uses the existing coolent to cool it. don't know if it works.

BlazerLT
12-18-2004, 04:09 AM
Can someone explain why letting hot exhaust gases in is going to cool the combustion chamber? I beleive it is actually just part of the emission system.

Exhaust temperatures are a lot cooler than combustion temperatures.

It is like you are saying the smoke is hotter than the fire.

Mikado14
12-18-2004, 10:49 AM
Can someone explain why letting hot exhaust gases in is going to cool the combustion chamber? I beleive it is actually just part of the emission system.

You are reducing the amount of oxygen for combustion by introducing inert gases from the exhaust which reduces the combustion temperature. By reducing the combustion temperature, the amount of NOx emissions are reduced. Oxides of Nitrogen are the main component is smog. The EGR is purely an emissions device and not performance.

Fireplug
12-18-2004, 11:52 AM
Mikado14
I would agree with everything you said and would add that by lowering the combustion temps that also reduces the chance of piston ping and that alone will help performance

metallica21156
12-18-2004, 10:32 PM
so does the EGR mod do anything or just nothing at all?

BlazerLT
12-18-2004, 11:43 PM
Mikado14
I would agree with everything you said and would add that by lowering the combustion temps that also reduces the chance of piston ping and that alone will help performance

Actually, it is also used as a anti detonation/ping system too.

Read this:

http://www.autoshop101.com/forms/h61.pdf

metallica21156
12-19-2004, 09:22 AM
thanks for the info. so should i leave the mod on or off?

BlazerLT
12-19-2004, 09:58 AM
Leave it off for now.

rlith
12-19-2004, 12:25 PM
The EGR mod is a good mod overall as you are still allowing NOx to 10%. It will give a slight power increase from low to midrange (but completely useless at WOT). It will increase your gas milege a mile or 2 per gallon. That said, if you want to completely eliminate the EGR without any engine problems. Get a blockoff plate, then you will need to get a new chip for your ECM that has the EGR (or anything else you want) deleted from the program. This will prevent the SES light from being set. Several places online will burn you a custom chip for your ECM. All they need is the current revision numbers off your existing chip. Just be aware that COMPLETELY blocking off your EGR will raise your emissions levels which can be a problem with inspection whereas just using the EGR mod will allow you to typically pass..(provided your egr ports aren't completely blocked with carbon)

Mikado14
12-19-2004, 12:32 PM
Mikado14
I would agree with everything you said and would add that by lowering the combustion temps that also reduces the chance of piston ping and that alone will help performance

Here's a question for you Fireplug, Since the combustion temperatures are higher, wouldn't a higher octane rating prevent the predetonation?

BlazerLT
12-19-2004, 01:14 PM
The EGR mod is a good mod overall as you are still allowing NOx to 10%. It will give a slight power increase from low to midrange (but completely useless at WOT). It will increase your gas milege a mile or 2 per gallon. That said, if you want to completely eliminate the EGR without any engine problems. Get a blockoff plate, then you will need to get a new chip for your ECM that has the EGR (or anything else you want) deleted from the program. This will prevent the SES light from being set. Several places online will burn you a custom chip for your ECM. All they need is the current revision numbers off your existing chip. Just be aware that COMPLETELY blocking off your EGR will raise your emissions levels which can be a problem with inspection whereas just using the EGR mod will allow you to typically pass..(provided your egr ports aren't completely blocked with carbon)

Also,you should tell them about the possible pinging and detonation caused by the higher combustion chamber temperatures which will cause your engine computer to retard the timing which will then cancel out all power increase you will get.

rlith
12-19-2004, 01:20 PM
Also,you should tell them about the possible pinging and detonation caused by the higher combustion chamber temperatures which will cause your engine computer to retard the timing which will then cancel out all power increase you will get.

That rarely happenes, and you found out what the problem was 7 months after we kept telling you it was something deeper didn't you?

BlazerLT
12-19-2004, 01:44 PM
Rarely happens?

And what are you talking about? Somehow I found out the problem? Nope, still causes pinging and still causes pinging after I tried to install it again.

I gave it a shot and it still causes the problem.

Not my truxk at all, it has everything brand new right back to the fuel tank and fuel pump replaced a month ago.

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