What is the intake plenum of the air flow sensor plate? My husband is trying to figure this out and the small picture in the Chilton book is not any help at all. There is a picture in that book in the fuel system section 5-22. Thanks.

 

Sorry I don't have a chilton book.
But what exactly is he looking to do?

 

I have a Chiltons. Section 5-5 Fig. 22 shows how to measure pressure at the fuel rail. My Chiltons only goes to Section 5-10. Form 1990-1998 manual. I am not sure what he is talking about, doesn't sound like the fuel rail.

 

This is the Continuous Injection (CI) fuel system used on early 240s. The injection valves are always open and the amount of fuel going into the engine is controlled by variation of the air flow as opposed to variation of the injection time. The air-fuel control unit consists of an airflow sensor and a fuel distributor.

The intake plenum on most cars is bolted directly on top ofthe intake manifold. It is also known as a venturi. The air flow sensor plate sits in the venturi. As the air flows upwards through the venturi the plate lifts to allow it to pass through.

The movement of the plate is transferred by a lever to the control plunger in the fuel distributor which regulates the amount of fuel to each injector.

Hopefully this will make it clearer:



[IMG]local://upfiles/4491/FC27C6773C594888A5845269E7A85C7B.jpg[/IMG]

 

First for darkdelta, it is in section 5-22 of Chilton but in the book for 1983 Volvos. For billofdurham, that picture looks nothing like what my husband is looking at in the volvo. He had to go by the thumbnail because the laptop would not download a bigger copy of the image. He is still learning on the computer so I type and find him information from these forums when he has a question. Besides, I work on computers all week and know how to run systems on these things. Anyways, he would like to know what the black boxin thepicture I put in this post does. It has a black cap that pulls off with a three wire connection underneath.

[IMG]local://upfiles/20685/0E7EB4362D8748DA970D63D7415F4A54.jpg[/IMG]

 

The picture is a little hard to make out but that looks like the DIAG plug that is on all the CI cars.

Never had to use one but I belive that is to hook a certain tool up and take readings.

 

That is the clearest I could get the picture which is better than what the book had. It shows him taking off the unit and it's only held by one nut/bolt on the valve cover.

 

I believe it is the Diag plug.