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View Full Version : Vaccuum valve rattles



BMS
11-19-2002, 09:46 PM
My 88 LX has, from what I could narrow it down to, a rattlng vaccuum valve. It rattles like the diaphrgm is torn and flappig free. it gets louder when the engine is straining. It is located directly in front of the carb/filter unit. It has threads on both ends and one sides takes a 90 turn straigt down, metal pipes(nt hoses) going into each end. very obvious. The valve itself is slanted sightly away frm carb. What does it do, how important is it, and can I replace it myself?

A20A1
11-19-2002, 10:45 PM
That is the AS-Valve (Air Suction Valve)
It adds fresh air to the Exhaust stream to help control emissions.

You can ulplug the vacuum hose form the AS-Valve and the rattle will stop... plug the hose to avoid a vacuum leak. It's not a major engine component... it's just there for emissions. I've never replaced one before... but I can tell you that removing the valve is a big job.

BMS
11-20-2002, 06:22 PM
I didn't even notice a hose. Maybe i should look closer. Another Q: I was quoted 300 for a timing belt change, including water pump. Since I 've never replaced one before, does this sound like a good deal?

shepherd79
11-20-2002, 08:13 PM
$300??? i think it is not bad deal for a timing belt and water pump change.

BMS
11-20-2002, 08:22 PM
That's what I figured, but best to make sure. I was quoted all the way up to 600! I can't afford to spend any extra money.

BMS
11-20-2002, 09:05 PM
Originally posted by A20A1
That is the AS-Valve (Air Suction Valve)
It adds fresh air to the Exhaust stream to help control emissions.

You can ulplug the vacuum hose form the AS-Valve and the rattle will stop... plug the hose to avoid a vacuum leak. It's not a major engine component... it's just there for emissions. I've never replaced one before... but I can tell you that removing the valve is a big job.

I disconnected the hose as advised, and it did absolutely nothing. I will have to remove the air filter housin this weekend and take another look. It's starting to worry me, it's getting loudr with time, and strange noises near the carb is probably someting to worry about.

A20A1
11-20-2002, 10:19 PM
k

A20A1
11-20-2002, 10:24 PM
That is the valve right?
I think the hose is #5 but I'm not totally sure.

if the valve is broken majorly then i can see it making noise even when the vacuum is not applied.

BMS
11-21-2002, 12:51 PM
That's the valve. I detached the hose and like i said it did nothing. This weekend I'll take a closer look. I know that it has to be something like a gasket or diaphragm by te way it sounds, not metallic at all. I've never done any work on a Honda. I'm guessing that the air filter housing is just held on by a few bolts?

shepherd79
11-21-2002, 12:53 PM
yeah, just to let you know that valve is a bitch to remove. you will need bigger than 22mm wrench.

BMS
11-21-2002, 01:09 PM
Do you think that maybe the carb/manifold gasket coud make that noise?

BMS
11-21-2002, 01:13 PM
Or i could be one of the other valves associated with the carb. Grrr.....my old car had a one of those go bad....I hope it's an easy fix and not the one I originally thought it was.

BMS
11-26-2002, 02:11 PM
Well, I went and saw a mechanic about the problem, and guess what he said? He said it is the ASV. He said the ASV uses a reed valve, and on older hondas the reeds just go bad with use, and produce the rattling. He also said that detaching the vaccuum hose usually makes it stop, but mine is a little wors than usual. It actually only takes 4 10mm bolts and a crescent wrench to get it off, and since it doesn't affect the engine directly, the onlyreason it would need to be replaced would be tosolve the annoying noise. He told me to go to the junk yard and pull one, maybe 10 min to get it off. Lucky me.

A20A1
11-26-2002, 05:02 PM
if all else fails you can take off the as valve and plug the pipe.

BMS
12-21-2002, 05:35 PM
I took the damn thing apart today to see what I could do. My junkyard didn't have one so I had to fix it myself. It was really, really easy to get off with a crescent wrench and a 10mm socket wrench. I took it apart and cleaned the reeds and then turned them upside down. I guess that over time they had gotten too flimsy and were just flapping around in there. So I flipped the reeds, put it together again, and re-installed it. I started up my car, and silence. I had fixed it. No more rattling noise! I am so happy now.

shepherd79
12-22-2002, 07:12 AM
glad to hear

Poodlehead
11-15-2007, 07:10 PM
BMS - Thank you for the info about taking it apart to fix the rattle. I did exactly like you suggested and ended up with the same great results. Those reed valves/flaps didn't make a tight seal so I was concerned that it would still make noise, but it did not.

Thanks! Now if I can just finger out why my steering column rattles when it's locked at idle. If I unlock it, it doesn't rattle...

steveko
11-17-2007, 10:12 AM
If in fact it is rattling and leaking would'nt that also cause the car too run like crap due too a vaccum leak. I too have this same problem if it's as easy too do as it sounds.I'll be fixing mine this week.

Poodlehead
11-17-2007, 07:53 PM
Mine was running good before with only one slight problem. It's like the accelerator pump is not working, but I know that's not the problem because I already changed that... I haven't driven the car yet and I don't think that will resolve my problem, but maybe I'll get lucky...

It is fairly easy to take off, a large cresent wrench on the big nut and then 10mm on the rest. Take the housing and the plastic box off together... When I took it apart I really didn't see anything wrong, but did the process suggested and it's quiet now.... Good Luck!

steveko
01-07-2008, 07:14 PM
Replaced mine this past Friday, nice too have a piece of mind having one less thing too repair.

A20A1
01-09-2008, 02:48 PM
interesting that you can just flip the reed :D glad it's fixed.

steveko
01-10-2008, 02:32 PM
I just cleaned mine up,with solvent bent them slightly so they would seal tighter. no need too really flip them.