Quote:
Originally Posted by Schrade
Where's Cliff here - is there a sequence / write-up for vac test with plenum dry - fit, with all electrical connections? Is it in FSM?
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Post #267 a bit before you were ready
Before you tighten down the Plenum (with Plenum tipped up in front) and ALL vacuum lines, and DIS module connections in place....check your vacuum systems.
With all vacuum lines connected, turn key on and listen for vacuum pump to shut off. If it does not shut off, start at the closest vacuum line to the vacuum pump disconnecting the line and holding your finger over the end. If the pump shuts off the leak is on other side of that. Go to next fitting and do the same until you are past the leak wherein the vacuum pump will NOT shut off. You have now located the leak.
Also check your HVAC and Cruize Control Vacuum System (check ALL connections). Also check your EVAP Purge system connections (charcoal canister which is under drivers side headlight on your 90'). That single small vacuum port under front of plenum facing rearward (90' only) is for the Evap Purge System. The second larger vacuum port on drivers side lower front of plenum is the main vacuum line for the Charcoal Canister. The second Vacuum port right next to that Charcoal Canister port is your PCV Vacuum port.
With the key on, ground the pink wire in the green connector (third from drivers side) on ECM. Use a small finishing nail stuck in alongside the wire connector with an alligator clip pigtail attached to the end for grounding. This will activate the Secondaries which you can watch with the plenum tipped up in front before you bolt it down. This after you are sure you have NO vacuum leaks in the Secondary System.
I promised GC I would not mention any modifications .....but you should eliminate TB coolant so you do not have to mess with coolant every time you remove the Plenum......DO NOT TELL GC I suggested this
Vacuum Systems 90' and 91' (Secondary and Cruize/HVAC)