Heat riser control diaphram supposed to hold vac?

[jaiden]

I repaired my heat riser valve by shortening the metal "paperclip wire" part. it seems to work now. But, when I put vac on it with a pump, it wouldn't hold vac.

Is it supposed to?

Now the car races (4000 rpm) even when it's warmed up. No stalling (icing) at least, just runs poorly.

Ideas?

[accordlxi2.0]

the only time that door should be open is when the engine is cold.
then once it warms up it'll go down.
you said it races (4000rpms) what do you mean??

[jaiden]

Yeah, it seems that it opens properly now, at least when it's warming up.

Now when I hit the clutch, and come off the gas , the rpm's go UP a touch before settling down.

then sometimes, I come off the clutch and the rpm's go to 4000 rpm or so. blipping the throttle doesn't help at all. Slipping the clutch to slow the engine usually calms it down to 2000 or so for a bit.

What i'm wondering is: 1) what could be wrong, and 2) is that valve supposed to be sealed airtight like the choke valve (for example) is? IE, when I put vac on the choke valve, the vac stays there. when I put vac on the heat riser valve, the vac leaks out (air leaks in, whatever).

could this much of a vac leak cause this prob?

[accordlxi2.0]

yep..mines was doing that..whenever the "ecu" whould send vac to that vavle.
so i simply plugged that line.
it does this when the engine is warm to fully warmed up right?
if so try this : once it does that try pulling the pedal with your foot and if the rpms goes down to it's normal idle i know what the problem is.....

[jaiden]

Pulling the pedal back, or blipping the throttle didn't help. I need the heat riser to keep from carb icing, so I can't just stop it off

are you saying that the valve should hold vac? (I'm guessing it should)

any idea where to get a replacement without getting raped by a dealership?

[accordlxi2.0]

ummm
what year is it?

as for finding one...i say try the j/y.

plus once the engine is luke warm the carb will be fine.
you even have a device where it warms the fuel up so the car won't run crappy.
i had a cai (even in the winter and i live in chicago) on my 86 lx and it did affect the carb.
now i belive the car did'nt have a t-stat or either it was stuck open.
but when i would drive on the highway and the gauge would go below the c line yea the car would run crappy, because of the either bad t-stat or no t-stat...

[A20A1]

Sounds like a vacuum leak is causing the vacuum pipe to leak vacuum which in turn bleeds vacuum from line #6 which is also connected to the pipe... the lower vacuum causes the idle diaphragm to raise the idle.

So you probably have a leak from line #8... under the air cleaner box or the line to the diaphram. But the diaphragm should onlyu get vacuum when the intake temp is cold.

[jaiden]

There's some kind of check valve (?) in the line on the way to the diaphragm.. maybe I cracked it? it makes a hissing noise with vac on it. is this a one way valve or what? how to test?

[jaiden]

oh and it's an 89 lx

[A20A1]

hissing is bad... try replacing the vacuum lines... or maybe the diaphragm is leaking...

I saw your other thread... you could of kept posting in this one, it makes things easier.