Vacuum unit next to coil - help needed
03-29-2006, 08:42 AM
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Vacuum unit next to coil - help needed
I drive a 1985 Audi t44 (non turbo) with the 2226cc engine and 5 speed gearbox. There is a vacuum unit situated next to the coil and I believe it has something to do with giving more petrol when you accelerate. What I would like to know is if there is supposed to be a hose connected to it or not, since it has a hose like fitting at the bottom. If there has to be a hose I would also like to know where on the engine it has to be connected.
<img src="http://pictureposter.audiworld.com/105681/dsc01781.jpg">
<img src="http://pictureposter.audiworld.com/105681/dsc01781.jpg">
03-29-2006, 10:51 AM
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Re: aint never seen one of them before , how does the car run how's the gas mileage
Fuel consumption is still pretty good for a car that's 21 years old, but the car does has a on/of hesitation when driving with and without giving throttle. I am going to get a new set of ignition leads tomorrow to see if there is any improvement.
03-29-2006, 11:01 AM
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I could be wrong but......
according to my Bentley I think that is a pressure gradient switch, which is used for emissions. It should have a vacuum hose going from it to a thermopneumatic valve. (not sure where this valve is) I don't have this on my car, and my Bentley manual is somewhat vague on it. I'm not sure if it's vital for this part to work correctly.
Randolph
87 5KCSTQ
93 928GTS
Randolph
87 5KCSTQ
93 928GTS
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03-29-2006, 11:53 AM
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I found the following, hope it helps:
>As an extension to the vacuum problem I have a question about this
>vacuum switch on the side of the head at number 5 cylinder. Is it
>supposed to have two hose barbs on it? I have two of these and they
>both have just one barb and one hole, but it looks like a second barb
>was broken off? It seems to be something to do with cold enrichment.
>Does anyone know how this subsystem works or can they point me to a part
>of the Bentley that describes it?
Yep, this is called the thermo-pneumatic valve, aka. thermo-vacuum valve. It was only put on the '85 turbos, and I think on many NA engines. Basically, it provides for additional full-throttle enrichement when the engine is cold. My engine had both barbs broken off, so I bought a new one from somebody on eBay. There's also a related pressure gradient switch. All the info is in the Bentley in sec. 26.35.
>vacuum switch on the side of the head at number 5 cylinder. Is it
>supposed to have two hose barbs on it? I have two of these and they
>both have just one barb and one hole, but it looks like a second barb
>was broken off? It seems to be something to do with cold enrichment.
>Does anyone know how this subsystem works or can they point me to a part
>of the Bentley that describes it?
Yep, this is called the thermo-pneumatic valve, aka. thermo-vacuum valve. It was only put on the '85 turbos, and I think on many NA engines. Basically, it provides for additional full-throttle enrichement when the engine is cold. My engine had both barbs broken off, so I bought a new one from somebody on eBay. There's also a related pressure gradient switch. All the info is in the Bentley in sec. 26.35.
