4-AF quiestion: broken pipe, motor revs-up???

Hello friends,
My car mechanic english vocabular is very poor so I hope that you will
understand what this is all about.

I have a very old Carina II XL with 4-AF engine since 1989. Yesterday
I've heard a sucking-whistling noise under the hood, and scared a lot
since I drive on LPG (i thought about LPG leak).
It appeared to be a broken pipe connection, and air was sucked into it.
Not a big deal but I noticed that engine rpm raised, and become
unstable on idle. I have put some screw to seal the pipe and everything
seems OK.

This broken part is a plastic one, located at the bottom of air-filter
canister on the right hand side near the carburetor (looks like it is a
part of air filter canister). It has two pipes comming out of it. A
thin one is going all the way to the front air inlet at the front side
of the car. Other thicker pipe is going somewhere at the bottom of the
carburetor or under it - I am not sure. The outlet on this plastic part
where the thick pipe comes has broken, so the air was comming in and
rpm rised as I described. Looking from the inside of air filter this
part has some big screw in it.

What is the purpose of this plastic part? What is it? This part is very
hard to find in my country, so I am asking about your oppinion if I can
continue to drive my Toyota this way, with this pipe sealed.

Max

On 13 Jan 2007 07:14:32 -0800, "Max" <grubicm@hotmail.com> wrote:
[color=blue]
>Hello friends,
>My car mechanic english vocabular is very poor so I hope that you will
>understand what this is all about.
>
>I have a very old Carina II XL with 4-AF engine since 1989. Yesterday
>I've heard a sucking-whistling noise under the hood, and scared a lot
>since I drive on LPG (i thought about LPG leak).
>It appeared to be a broken pipe connection, and air was sucked into it.
>Not a big deal but I noticed that engine rpm raised, and become
>unstable on idle. I have put some screw to seal the pipe and everything
>seems OK.
>
>This broken part is a plastic one, located at the bottom of air-filter
>canister on the right hand side near the carburetor (looks like it is a
>part of air filter canister). It has two pipes comming out of it. A
>thin one is going all the way to the front air inlet at the front side
>of the car. Other thicker pipe is going somewhere at the bottom of the
>carburetor or under it - I am not sure. The outlet on this plastic part
>where the thick pipe comes has broken, so the air was comming in and
>rpm rised as I described. Looking from the inside of air filter this
>part has some big screw in it.
>
>What is the purpose of this plastic part? What is it? This part is very
>hard to find in my country, so I am asking about your oppinion if I can
>continue to drive my Toyota this way, with this pipe sealed.
>
>Max[/color]

Propane/LPG conversions are not that common, and are often done
"custom" for each car - so we'd be flat out guessing. But if you plug
up the vacuum leak temporarily and it runs right, I wouldn't worry too
much.

Do you have any paperwork that came with the car as to who made the
LPG conversion equipment - the gasifier, the "carburetor" (metering
valve), etc.? If not, look under the hood and write down any
identifying names and model numbers on the parts.

If you have a digital camera, take pictures of the fuel system parts
and put them in your ISP Personal Webspace account, and put a link to
get there here - you aren't supposed to post pictures in the
newsgroups directly. Be sure to get pictures of the part that cracked
that you sealed up. Someone may recognize who made it and can give
you better information.

IMPCO is a common maker of LPG conversion equipment, and they are in
California. About 30 miles from here.

--<< Bruce >>--

"Max" <grubicm@hotmail.com> wrote in message news:1168701268.014438.302990@m58g2000cwm.googlegroups.com...[color=blue]
> Hello friends,
> My car mechanic english vocabular is very poor so I hope that you will
> understand what this is all about.
>
> I have a very old Carina II XL with 4-AF engine since 1989. Yesterday
> I've heard a sucking-whistling noise under the hood, and scared a lot
> since I drive on LPG (i thought about LPG leak).
> It appeared to be a broken pipe connection, and air was sucked into it.
> Not a big deal but I noticed that engine rpm raised, and become
> unstable on idle.[/color]


It may help to imagine that as if it was a straw with a hole in it
that you are using to drink a soda pop.



I have put some screw to seal the pipe and everything[color=blue]
> seems OK.[/color]


Now imagine thats your finger over the hole. 8)
[color=blue]
>
> This broken part is a plastic one, located at the bottom of air-filter
> canister on the right hand side near the carburetor (looks like it is a
> part of air filter canister). It has two pipes comming out of it. A
> thin one is going all the way to the front air inlet at the front side
> of the car. Other thicker pipe is going somewhere at the bottom of the
> carburetor or under it - I am not sure. The outlet on this plastic part
> where the thick pipe comes has broken, so the air was comming in and
> rpm rised as I described. Looking from the inside of air filter this
> part has some big screw in it.
>
> What is the purpose of this plastic part? What is it? This part is very
> hard to find in my country, so I am asking about your oppinion if I can
> continue to drive my Toyota this way, with this pipe sealed.
>
> Max
>[/color]

Ray O је напиÑ?ао
[color=blue]
>
> It is difficult to tell for sure what you are talking about, but it sounds
> like the pipe you are describing is the pipe that brings air from the air
> filter to the carburetor. I would repair with plastic cement, a hose clamp,
> or duct tape. A black plastic pipe over 3 cm diameter is probably for fresh
> air intake.
> --
>
> Ray O
> (correct punctuation to reply)[/color]

Ray,
the pipe is not that thick, and seems like going directly to the hm ...
what is the word ... we say "intake branch" or "intake distributor"
here, this "milti-piped thing that comes under the carburetor and
distributes the fuel-air mixture to the cyliders".

Let me describe once again:
I know what is the main air-ducting huge pipe-like thing that brings
fresh air to the air-filter. But somewhere at the begining of main air
intake at the front of the car, another small plastic 5mm thick pipe
comes out and reaches this plastic part in the the air filter canister
that I have desribed. From this part another thicker pipe (about half
inch or 1-2mm) goes directly under the carburetor. If this pipe is
open, motor revs-up and works unstable. If I close it, it looks-like
working normaly. So if that is what you think it is, what is that thing
for?

I was wondering if that thing has something to do with a automatic
choke system or fuel-air mixture, because if the pipe is open
additional air is coming and meshing with already prepared mixture.

If you guys have some photo, blueprint or web lolcation with Toyota
repair manual with all parts of the cerburetor system on it I might
show you what pipe is the problem.

Max

"Max" <grubicm@hotmail.com> wrote in message
news:1168777998.121513.254600@m58g2000cwm.googlegroups.com...

Ray O ?? ???????
[color=blue]
>
> It is difficult to tell for sure what you are talking about, but it sounds
> like the pipe you are describing is the pipe that brings air from the air
> filter to the carburetor. I would repair with plastic cement, a hose
> clamp,
> or duct tape. A black plastic pipe over 3 cm diameter is probably for
> fresh
> air intake.
> --
>
> Ray O
> (correct punctuation to reply)[/color]

Ray,
the pipe is not that thick, and seems like going directly to the hm ...
what is the word ... we say "intake branch" or "intake distributor"
here, this "milti-piped thing that comes under the carburetor and
distributes the fuel-air mixture to the cyliders".

Let me describe once again:
I know what is the main air-ducting huge pipe-like thing that brings
fresh air to the air-filter. But somewhere at the begining of main air
intake at the front of the car, another small plastic 5mm thick pipe
comes out and reaches this plastic part in the the air filter canister
that I have desribed. From this part another thicker pipe (about half
inch or 1-2mm) goes directly under the carburetor. If this pipe is
open, motor revs-up and works unstable. If I close it, it looks-like
working normaly. So if that is what you think it is, what is that thing
for?

I was wondering if that thing has something to do with a automatic
choke system or fuel-air mixture, because if the pipe is open
additional air is coming and meshing with already prepared mixture.

If you guys have some photo, blueprint or web lolcation with Toyota
repair manual with all parts of the cerburetor system on it I might
show you what pipe is the problem.

Max

*******
I am having trouble trying to picture what you are talking about in my mind.
It may be part of the compressed gas conversion, but if it is going from the
air filter to the intake distributor (known as an intake manifold in the
U.S.) then it probably only has air passing through so it is safe to repair
with tape.
--

Ray O
(correct punctuation to reply)

Should be able to find what is what on your car looking around AutoZone.com.

Here is a link to a (wild guess) 1989 Toyota Corolla 1.6L EFI DOHC
PVC system for example.
[url]http://www.autozone.com/servlet/UiBroker?ForwardPage=/az/cds/en_us/0900823d/80/16/a4/06/0900823d8016a406.jsp[/url]

GL
Dan