[Body man]

Working on my 1998 and cleaning up engine compartment and just noticed a braided looking pipe with metal ends that screw into the rear of left exhaust manifold with the other end screwing direct into intake manifold near front with no EGR valve. I've always blocked/removed egr systems on my chevy smallblock engines but I've never seen this..Does this mean exhaust gas is constantly going into intake or am I missing something on these 4.3's ?

 

[spudder15]

If we're talking about the same pipe, this pipe doesn't bolt into the exhaust manifold it sits into a heat shield around the exhaust manifold (RHS of engine..?)
There is a little "do-da" in the intake that regulates a flap for your air intake. The heat of the exhaust manifold travels up that pipe causes this flap to move, if I recall correct.
Look for something like this part at the rear upper end of the engine block for the EGR.
Duralast EGR Valve EGR1092 (autozone.com)

 

[Body man]

If we're talking about the same pipe, this pipe doesn't bolt into the exhaust manifold it sits into a heat shield around the exhaust manifold (RHS of engine..?)
There is a little "do-da" in the intake that regulates a flap for your air intake. The heat of the exhaust manifold travels up that pipe causes this flap to move, if I recall correct.
Look for something like this part at the rear upper end of the engine block for the EGR.
Duralast EGR Valve EGR1092 (autozone.com)

I haven't paid much attention to the right side of engine so this may be there. The pipe I'm talking about has a large fitting that screws directly into the top rear of the left cast iron exhaust manifold, the other end has fitting that screws directly into intake at left front behind computer temperature sensor. The pipe itself is over an inch in diameter and is braided material like stuff that seems soft to squeeze like the actual metal tube must be smaller and the outside is some type of insulation..

 

[VanLover]

I haven't paid much attention to the right side of engine so this may be there. The pipe I'm talking about has a large fitting that screws directly into the top rear of the left cast iron exhaust manifold, the other end has fitting that screws directly into intake at left front behind computer temperature sensor. The pipe itself is over an inch in diameter and is braided material like stuff that seems soft to squeeze like the actual metal tube must be smaller and the outside is some type of insulation..

It doesn't make sense to me to feed unmetered exhaust gases into the intake.
Can you post pictures? What's a "computer temperature sensor"?

 

[Body man]

It doesn't make sense to me to feed unmetered exhaust gases into the intake.
Can you post pictures? What's a "computer temperature sensor"?

Well I sent and got a 3 volume set of the factory service manuals for a 1998 astro van and this is a gold mine of information. I found out the tube I was looking at does go directly from the exhaust manifold to the intake, but inside the intake is a passage way that leads up into the EGR valve so the exhaust gases are still controlled by the EGR valve. Just a different way of routing it compared to the older small blocks. The computer temperature sensor is located at the front next to the EGR valve and the thermostat housing, it's called an ECT it sends signals to the engine computer. Still figuring how much " cleaning up" of unneeded stuff I'm going to remove from this van,,,,,,,

 

[VanLover]

Thanks for the info.
I know where to find my EGR valve, but never tried to trace the path of the EGR gases. I'm curious now; I'll take a closer look at my own van when I can.
I was confused, I thought "computer temperature sensor" is a sensor that reads the computer's temperature. 😆😆
(ECT= Engine Coolant Temperature)

 

[Mwood]

EGR is standard equipment on smog legal vehicles.
the flow of gas directly from exhaust manifold into the intake plenum is metered by an EGR valve which on our engines is on the front of the intake manifold below the thermostat

How Does A Vehicle EGR Valve Work?

m.smogtips.com