Idle Diaphram not pulling

[88accordlxcarb]

Problem:

Car started having high idle(warm and cold) around 2,000-3,000. This started after no changes to the car, randomly. Diesels when turned off.

I took the vacuum line going to the idle diaphram off(the one that looks to have some sort of check valve on it, that leads directly into the diaphram), and the idle surged, and when i put it back on, the idle resumed to a normal position(1,000ishRPMs). I took the line off again and stuck my mouth on it and sucked in. The small amount of vacuum i created made the idle go down a little.

I thought i had fixed the problem, maybe it was just stuck somehow. The car continued to run with the correct idle for around half of one day. The car was started in cold weather, idled correctly and parked all day. When started for the 3rd(not second) time that day, the idle went back to the constant high idle.

I know the idle diaphram is screwing up somehow. What causes this? Can this diaphram stick, or is it a vacuum problem going to the diaphram? If so, where should i be lookingAll hoses appear to be fine, but i dont have a vacuum tester at school with me.

Car: All Stock.

[A18A]

i dunno if you wanna, but i just ditched the diaphram and set the idle with the throttle stop screw, worked fine for me but it might not be recommended though

[nskforlife]

my car has kinda the same problem, when i turn it on, it idles depending on how much gas is in the carb i guess. it'll idle high for like the 1st couple runs through the gears then the idle goes back to normal. usually when it idles high i just slam the gas for a split secong and then it drops to normal. i dont know what the problem is. but it doesn't bother me cause it's a carburator. if it pissed me off enough i'd go fi.

[A18A]

thats normal, it just idles high cause its cold lol. i would like a good carb like that

[88accordlxcarb]

This is not just a cold idle problem. This continues to happen when the car is fully warm. This also started suddenly, so something happened. There is a leak somewhere or something is malfunctioning, I am just not sure what.

[A20A1]

See if the diaphragm holds vacuum when you apply the vacuum pump... other then that it sound like the diaphragm is working... so just check for vacuum leaks elsewhere.
https://www.3geez.com/forum/showthread.php?t=53700

[88accordlxcarb]

A small hole in the vacuum line going to the idle diaphragm.

A post just so people searching in the future will know, to closely examine your vacuum lines, as a pin sized hole can cause a world of trouble.