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Is the 'Emission Hose Routing' label missing on your 1991?
Actually I removed it last night not paying attention to mark all lines..
I know one is for the fuel pump regulator, and one for the MAP… but can’t figure out the 3rd one…
To a Vacuum Check Valve distribution device that would do vacuum for cruise, vacuum storage tank, HVAC etc.
Yes it has 3 outlets, one to EGR solenoid then TB, one to vacuum tank with a T on the way hose goes all the way back to firewall and so the 3rd will go the plenum?
what about the EGR valve where does it connect to?
I got the information from my 1990 L98 GM SM. I hope it helps...
#2 goes to the EGR valve or Fuel Pressure Regulator (whichever one the plastic tube naturally goes to, #1 or #3 goes to the MAP sensor, and the remaining one goes to the egr or fpr. The vacuum from the purge canister goes to the throttle body.
I got the information from my 1990 L98 GM SM. I hope it helps...
#2 goes to the EGR valve or Fuel Pressure Regulator (whichever one the plastic tube naturally goes to, #1 or #3 goes to the MAP sensor, and the remaining one goes to the egr or fpr. The vacuum from the purge canister goes to the throttle body.
thanks,
but what about the EGR solenoid that is connected to the thermostat water neck? I know one hose goes to it from the plenum…
what I can’t figure out is the EGR valve under the plenum!! Where does it connect to 🤔
This I believe is correct. The forward port (#3) goes to the HVAC - it routes in front of the distributor and connects to a two-port, check valve on the left side of the engine - one side to the HVAC, and the other to the cruise control module. there might be another "tee" in the line going to the emissions system. the middle port (#2) connects to the fuel pressure regulator, and the aft port (#1) to the MAP sensor. I confirmed the MAP port using a '91 FSM.
This I believe is correct. The forward port (#3) goes to the HVAC - it routes in front of the distributor and connects to a two-port, check valve on the left side of the engine - one side to the HVAC, and the other to the cruise control module. there might be another "tee" in the line going to the emissions system. the middle port (#2) connects to the fuel pressure regulator, and the aft port (#1) to the MAP sensor. I confirmed the MAP port using a '91 FSM.
appreciate the help. As you mentioned I’m aware of #1 & #2 ports (MAP & FPR) that’s right…
now I have a check valve with 3 outlets: one connected to the EGR solenoid (and from there to TB), one connected to the vacuum tank (front driver side) with a T in the middle going to the back of the engine somewhere! And the 3rd outlet connects to the plenum (#3) in my photo…
The question is WHERE does the EGR valve (under the plenum) connects!!
it’s driving me crazy …
Thanks all for the feedback but still cant figure out the connections.
I checked some old photos and I have the Check Valve and it is connected as follow (As per the numbers):
#1 is connected to the plenum (passenger side)
#2 is connected to EGR Solenoid
#3 is connected to the vacuum tank (driver front side) on the way there is a T connection with a hose going to the back of the engine.
now the EGR valve (under the plenum) where should it be connected??
It should be (in no particular order) MAP sensor, EGR solenoid, and Fuel Pressure Regulator. The one of the check valve nipples goes to the HVAC, and your vacuum tank to the the Throttle Body. I could be wrong, there's other diagrams showing otherwise. But that's what I get from everyone's input. Hopefully someone with a '91 will chime in and share their diagram.
Back again…. as mentioned by others got all the 3 outlets on the plenum passenger side sorted out (one for FPR, one for MAF sensor and 3rd one to the EGR solenoid)… BUT Still can’t figure out where the EGR valve outlet connects to :
