Lt1 EGR help.
Thread Starter
Teching In
Joined: Jul 2012
Posts: 27
Likes: 0
Lt1 EGR help. Hi, so heres the story. The guy that owned my car before me (a 1993 t/a) has removed the egr system from the car. I was wondering what I have to do put it back on due to emissions where I live. (he lived in an emissions free area) The car was having trouble passing and we found I did not have a catalytic converter and the egr had been removed.
I have just had all my machining done and I am now putting the motor back together.. I want to put it back on so I can pass... How am I going to go about doing this? I have an intake that is untampered. I still have stock headers with the piping running out of the top. How ever as soon as I trace it back it is missing something that would connect them to the EGR possibly? I am confused.
Is it worth my time to even to put all this back? Could I pass with just replacing the cat and the fresh motor?
Any help and all help is very appreciated.
-Kyle
**I'll upload pics if any are interested in seeing every thing that was machined ect...
I have just had all my machining done and I am now putting the motor back together.. I want to put it back on so I can pass... How am I going to go about doing this? I have an intake that is untampered. I still have stock headers with the piping running out of the top. How ever as soon as I trace it back it is missing something that would connect them to the EGR possibly? I am confused.
Is it worth my time to even to put all this back? Could I pass with just replacing the cat and the fresh motor?
Any help and all help is very appreciated.
-Kyle
**I'll upload pics if any are interested in seeing every thing that was machined ect...
Most people remove the EGR valve and use a block off plate on the intake manifold and a bung on the exhaust manifold. Hopefully you can remove the plate and reinstall the EGR valve. It's vacuum operated so make sure you have the vacuum hose installed. I highly recommend you purchase the EGR valve from a Chevy/ GM dealer. They will use the VIN # to get you the correct part. Reason being there is a negative backpressure EGR valve and a positive backpressure EGR valve used on the 4th gen. There is also a EGR tube that runs from the back of intake manifold near the valve to the rear of the passenger side exhaust manifold. Now for the tubes coming off the exhaust manifolds, those are not EGR related, they are part of the secondary air injection. Both are emissions related. You will also want to put the catalytic converter back on.
Last edited by musclehead; Sep 26, 2013 at 11:41 PM. Reason: Left out info
TECH Veteran
Joined: Dec 2008
Posts: 4,145
Likes: 61
From: Little Rock, AR
... There is also a EGR tube that runs from the back of intake manifold near the valve to the rear of the passenger side exhaust manifold. Now for the tubes coming off the exhaust manifolds, those are not EGR related, they are part of the secondary air injection. Both are emissions related. ...
Just a thought: Are you concerned with visual emissions compliance? or just the tailpipe sniff at idle?
I'm not positive, but I believe EGR is not commanded by the PCM at idle in the F-cars, only at high vacuum cruise. So, your NOx numbers at idle are not affected by a functioning vs. non-functioning EGR.
I'm not positive, but I believe EGR is not commanded by the PCM at idle in the F-cars, only at high vacuum cruise. So, your NOx numbers at idle are not affected by a functioning vs. non-functioning EGR.
TECH Veteran
Joined: Dec 2008
Posts: 4,145
Likes: 61
From: Little Rock, AR
Just a thought: Are you concerned with visual emissions compliance? or just the tailpipe sniff at idle?
I'm not positive, but I believe EGR is not commanded by the PCM at idle in the F-cars, only at high vacuum cruise. So, your NOx numbers at idle are not affected by a functioning vs. non-functioning EGR.
I'm not positive, but I believe EGR is not commanded by the PCM at idle in the F-cars, only at high vacuum cruise. So, your NOx numbers at idle are not affected by a functioning vs. non-functioning EGR.
