Vacuum Woes

[thozf]

I know among other things that I have a vacuum leak. If the car idles, the RPM's drop when I pump the brakes. Does this point me tward any particular lines, or could it be any of the lines? I have an 89 accord. I believe everything is stock.
Thanks :sadwave:

[DanG86LX]

Is the big like 1/2" rubber line going to brake booster, attached to the firewall @ driver side, has a check valve right above carb..
If the drop is like 50rpm, dont worry about (mine is doing the same), after all those vac lines, solenoids and valves should somehow "controlled" leak to work..
But if the drop is like 300rpm, i would worry about!

[thozf]

Yeah, mine is a pretty substantial drop in RPM. I also need to check the timing again. I recently overheated and cracked the head. When I put the replacement on I found that someone had timed it to the 15BTD mark instead of the T. So I fixed that, but it still ran like crap. It looked like I may have been a tooth off so I pulled it apart and moved it a tooth. That only made it worse. I am going to check it tonight and make sure it still isn't off. Also the gas petal feels really stiff now which could either be that I put a small kink in it trying to move it out of the way when I was working on the head, or the carb is completely gunked up. Gonna check all that tonight. I also think it is a bit low on ATF. Too many variables at this point. At least it has a new battery now.

[accordlxi2.0]

this may sound wired but if the a/f screw is'nt adjusted right, that could also contribute.

i mean . . .it's weird if the screw is too out then the idle will raise as you pump the brake's if it's too in the idle will go down.

[thozf]

Where is said A/F Screw locaced?

[A20A1]

well if it's off a tooth then you should readjust/check the valve lash just to be safe.


Also the A/F screw shouldn't be touched if it hasn't fallen out, or hasn't been played with previously.

[thozf]

I just checked the valves. They were all close. Some a little tight, but not too bad. This car has had some idle problems since I have owned it. Usually only when at stop signs. Shakes and rattles. I just would like to get everything closer to right while I am in there. I am also tired of standing on the side of the road waiting for someone to pick my ass up every time this thing craps out on me.

[thozf]

OK. Readjusted timing 1 tooth. It looks perfect on top and bottom. Timed it and ran ok. Here is today's quandry. When I am running down the road it is ok, but when I let off the gas the throttle dips down to below the first mark(333?) on the tack. If I get on the brakes it will drop to where it almost stalls. It also seems to be running hot. The thermostat is steady just below half, but at times I can smell antifreeze. New radiator, new thermostat, new waterpump. Any ideas?

[Mike's89AccordLX]

Ok I want you to do this check with all the windows rolled up and start the car and then shut it off. Then slowly press your brake to the floor and tell us what sound it makes. It should make a whoooshhh sound slowly whooshhhing and then as you press the brake further and further it should increase the whoosshh sound. Let me know what you find out.

And then try this test. Start the car and then shut it off and the pop the hood and take the check valve off the outside of the brake booster. And tell us what you hear.

[thozf]

Tried both tests. How far should the brake pedal travel? Mine doesn't go very far before it it stops, but it does make a slight "Wooshing" sound.
As for opening the check valve for the brake booster sounded like opening a beer. Pffft. :cheers:

[accordlxi2.0]

as for the pedal travel that's good.
as for the temp being a little under the half mark, that's okay, as long as the fans turn on, and it's not leaking antifreeze.
as for that anti-freeze smell, hmm that's common on some gm cars.
the only time i smelled anti-freeze is when i turned my heater on.

the a/f screw is located behind the carb in the middle of it, sometimes it has a cap and you would have to take a few things off to get to it.

hmmm if your car is idleing at 200rpms in drive set, the throttle stop screw should be adjusted.
my 86 was adjusted at 200rpms on purpose. i liked it too! not many things vibrated due to the broken rear mount.

[Mike's89AccordLX]

Well it sounds like your Vacuum booster is doing it's job and all of its components. I was affraid either your vacuum booster check valve is bad or your air control valve was bad. But from what you said those sound to be good so time to start checking other places.

[thozf]

It usually idles around 700. It is only idling around 200 when I have been driving and take my foot off the gas. I guess the choke is holding the idle up until it warms then once it is warm it relies on the stop screw for proper idle?

[accordlxi2.0]

ehhh no. with the coke fully closed your car would'nt run at all.

[thozf]

How is this then, once the car is warm it will only idle at 200 rpms. In the morning when I go out it fires right up and maintains a 900-1200 rpm even with the brakes pushed in. I drive about 3 miles of rural highway that comes to a stopsign. When I come to a stop at the stopsign the rpms drop below 200 then comes up to just below the 333 rpm marking on the tack(brakes still pressed). It will continue to do this at every stopping point until I get to the daycare where I drop off my son. If I turn off the car, when I get back in, it it starts fine and idles near the 900-1200 rpm mark like it did before, only now I barely get to the end of the block before the symptoms reoccour. ???? :help:

[accordlxi2.0]

but when you let go of the brake's, does the idle go back up.
if not, i think you should adjust the stop idle screw up some more.