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Vacuum question/ problem

1090 Views 12 Replies 9 Participants Last post by  EastTennBimmin
ok so i have a little problem i have a place on the back of my intake manifold where there should be a vacuum line so i caped it and after i did it made the car start idling low and almost dying out so i took the cap of and it started idling like it has been again at around 800-1000rpms very confused as to why it would idle down with it on but be fine with it off.

The only repercussion with it off it whistles when i get around 5000rpms, but i did drive it a little with the vacuum cap on and it seamed a lot fast with it on but won't idle not sure why and advise would be helpful. :thumbup:

also this is on a honda civic with a b16b with stock civic type-r intake manifold.

also here is a pic of the vacuum port it is on the back left off the intake manifold near the brake reservoir.

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the fpr hooks up to the front of the intake manifold at the top towards the engine. i think maybe it went to the charcoal canister? but not sure why capping it would make it idle down.
Cause you were sucking air in.When at idle only air that should be entering the intake is through the idle air control valve.You had more air that was being picked up by the ecu through the map sensor so it idled it up.Basically the car thought you were sitting still and had the gas pedal mashed to where the throttle was partially open.
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