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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

Reply to
Max
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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.

Reply to
Ray O

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.

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Reply to
Bruce L. Bergman

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

Now imagine thats your finger over the hole. 8)

Reply to
Danny G.

Ray O =D1=98=D0=B5 =D0=BD=D0=B0=D0=BF=D0=B8=D1=81=D0=B0=D0=BE

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

Reply to
Max

Ray O ?? ???????

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.
Reply to
Ray O

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.

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GL Dan

Reply to
Danny G.

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