MuniArt
01-28-2014, 05:48 PM
On an '88 Accord DX with auto tranny:
Anyone know what the full operation of the air vent cut-off diaphragm is? It is the diaphragm built into the side of the carburator thermovalve which is on the upper front drivers side of the carb. Mine has a bunch of holes from being so close to the fuel (it looks like its only a couple inches away from the internal float resevoir.) I can't interpret the factory vacuum diagram for this part to see what it does exactly. I know when the car is running vacuum is provided to the diaphragm (line 8) pulling a plunger to seal off the carb thermovalve inlet from the canister. When the car is off vacuum is not there and the plunger is pushed via a spring in the other direction to block off a different passage in the carb.
My diaphragm had lots of holes so I plugged line 8 going to it with a ball bearing to stop the vacuum leak. My question is this: does the air-vent cutoff plunger need to be open when running or does it not make any difference to the engine operation. I could theoretically plug the thermovalve inlet line instead and remove the plunger to open the passage inside the carb. Should I?
BTW, I also found my canister purge control valve diaphragm doesn't hold vacuum, so I plugged that line as well (line 19) at the canister. So I assume the canister never gets purged now. Is that a correct assumption? Does it eventually build up and vent out the bottom hose or something?
Also my anti-afterburn control solonoid valve wouldn't hold a vacuum so I plugged that line as well. That should be fine, right?
Lastly, my hot air door actuator is shot so I temporarily plugged that line while I look for a replacement.
I've been hunting for a cause for the high idle on this car. I thought for sure all these leaky diaphragms were the cause. I also found and repaired a couple vac hose leaks. Still idling high even when warm. Lowest I can get it is around 1300 RPM. And it likes to climb.
Any ideas, anyone?
Thanks. Sorry about the long post.
Anyone know what the full operation of the air vent cut-off diaphragm is? It is the diaphragm built into the side of the carburator thermovalve which is on the upper front drivers side of the carb. Mine has a bunch of holes from being so close to the fuel (it looks like its only a couple inches away from the internal float resevoir.) I can't interpret the factory vacuum diagram for this part to see what it does exactly. I know when the car is running vacuum is provided to the diaphragm (line 8) pulling a plunger to seal off the carb thermovalve inlet from the canister. When the car is off vacuum is not there and the plunger is pushed via a spring in the other direction to block off a different passage in the carb.
My diaphragm had lots of holes so I plugged line 8 going to it with a ball bearing to stop the vacuum leak. My question is this: does the air-vent cutoff plunger need to be open when running or does it not make any difference to the engine operation. I could theoretically plug the thermovalve inlet line instead and remove the plunger to open the passage inside the carb. Should I?
BTW, I also found my canister purge control valve diaphragm doesn't hold vacuum, so I plugged that line as well (line 19) at the canister. So I assume the canister never gets purged now. Is that a correct assumption? Does it eventually build up and vent out the bottom hose or something?
Also my anti-afterburn control solonoid valve wouldn't hold a vacuum so I plugged that line as well. That should be fine, right?
Lastly, my hot air door actuator is shot so I temporarily plugged that line while I look for a replacement.
I've been hunting for a cause for the high idle on this car. I thought for sure all these leaky diaphragms were the cause. I also found and repaired a couple vac hose leaks. Still idling high even when warm. Lowest I can get it is around 1300 RPM. And it likes to climb.
Any ideas, anyone?
Thanks. Sorry about the long post.