vacuum delay valves

[Bobby88GW]

On the air cleaner "trap doors"(2),how many seconds-delay vacuum valves do I need?

[RWalker]

I dont know the actual seconds, but they are more of one way valves than delay valves. You can get the ones from the air cleaner at autozone.

[badaboom]

Off the top of my head I am going to say 2
one goes to each "trap doors"(2).

[DjD]

The 1990 TSM calls them "reverse delay valves". It says the rdv provides approx. 100 seconds of delay before allowing the trap door to "completely" close.
Test: remove vac hose from end of valve that is not black. Apply external vac of approx. 2 to 4 in. Hg.
Using a stopwatch, note the time required for atmospheric pressure to pass through the valve and eliminate vacuum.
Replace valve if time required to eliminate vacuum is less than 4.5 seconds or more than 13.2 seconds.

[pensky2]

DJD
Try a strip of vecro on that cruise module. It worked on mine!

[andy d]

i wired the trapdoor shut and the cold air flap open. i saw this advice some where and it eliminates about 3 feet of vacuum hose.

[Ernzo]

ummmm, if the trap door is shut, then I think you have bigger problems. Both ought to be wired open. I think thats what you meant to say.
But, they do actually preform a valuable service to you an the air. Getting them correct is not really too hard.

Vacuum hose is cheap. Gassy oil can be expensive. Very.

[DjD]

I believe the trap door is to get some heated air in there before the engine is totally warmed up, so maybe a drive-ability problem until then. Wiring the cold air door open could cause very scared mice to defecate all over your air filter.

[andy d]

yeah, but all the stuff thats supposed to attach to the trap door is all gone away. entropy happens :D jeep started fine in 15'f temps after sitting a week.