Need Help, What the heck is this?

[TDIDog]

Pulled my intercooler & aircleaner & did some looking around at my engine checking hoses etc & noticed under the fuel distributor what looks like a sensor & I have no idea what it is. Nothing is connected to it, but there is a wire connection close by that is not hooked to anything. Connector doesn't fit the sensor, so I don't know if they go together. Can anybody tell me what this & how to connect it up?
Thanks in advance.

[sundevil64]

That looks like the plug that goes on the WUR.

[Helmsy]

2 prong one is a thermoswitch for the red vacuum line from the throttle body to the distributor pot.

The power connector (presuming you have an alternative one connected to your wur) is probably for a solenoid valve that is for the startup/emission control which also is connected into the vacuum line to the distributor.

I would say someone has removed the solenoid and just connected the vacuum line direct from the distributor to the throttle body.

Do a search on here and there are lots of posts about it but it is fine to run without it and most believe it is for emissions/startup based thing.

[mark houghton]

Originally Posted by helmsy

2 prong one is a thermoswitch for the red vacuum line from the throttle body to the distributor pot.

The power connector (presuming you have an alternative one connected to your wur) is probably for a solenoid valve that is for the startup/emission control which also is connected into the vacuum line to the distributor.

I would say someone has removed the solenoid and just connected the vacuum line direct from the distributor to the throttle body.

Do a search on here and there are lots of posts about it but it is fine to run without it and most believe it is for emissions/startup based thing.

+1^^^^

[TDIDog]

That would explain way it won't idle till it warms up a bit, then seams to run fine.
Thanks you guys. I guess I'll start looking for more parts.

[JFairman]

The short version is leave them disconnected becasue the car will run better that way. If you have a catalytic converter and need it working to pass emissions then reconnect them.

The mechanical one with two hose nipples is a thermovalve that is origonally in the red vacuum advance line. When the motor is cold or just a little warm it blocks throttle body venturi vacuum from reaching the vacuum advance pot on the distributor. The result of that is retarded ignition timing above idle speed and that raises exhaust temperature because combustion is happening later in the cycle and the last of the air fuel mixture is still burning as the exhaust valve opens.

The purpose of that is to raise exhaust temperature to heat up the catalytic converter faster after a cold start so the car will pass emission testing sooner. Once the motor has heated up and transferred heat to that thermovalve enough it slowly opens and lets vacuum advance reach the distributor's vacuum advance pot advancing timing above idle and increasing power output.

The electrical plug goes to the frequency valve that may or may not still be on the fuel distributor. It is not really a "solenoid valve" and neither it or it's controller ever goes near any source of vacuum.
A solenoid valve is slow acting and is either open or closed and would over heat and burn out fast if you did open and close it quickly continuously.
A frequency valve opens and closes continuously at a variable high speed making a buzzing sound.
It is an electronic fuel injector with no fuel spray pintle. Instead it has fuel line fittings on both ends so it's an inline electronic fuel injector being used to meter fuel flow through a line and it's called a frequency valve or pulse valve.

The frequency that it opens and closes is controlled by the k-jetronic lambda box or ECU under the driver seat and the lambda ECU uses an oxygen sensor in the exhaust header before the turbo and a temperature sensor in the right side chain case cover as sending units to compute the high speed on/off electrical pulse signals going to the fequency valve.

[oilonly]

Originally Posted by JFairman

The short version is leave them disconnected becasue the car will run better that way. If you have a catalytic converter and need it working to pass emissions then reconnect them.

The mechanical one with two hose nipples is a thermovalve that is origonally in the red vacuum advance line. When the motor is cold or just a little warm it blocks throttle body venturi vacuum from reaching the vacuum advance pot on the distributor. The result of that is retarded ignition timing above idle speed and that raises exhaust temperature because combustion is happening later in the cycle and the last of the air fuel mixture is still burning as the exhaust valve opens.

The purpose of that is to raise exhaust temperature to heat up the catalytic converter faster after a cold start so the car will pass emission testing sooner. Once the motor has heated up and transferred heat to that thermovalve enough it slowly opens and lets vacuum advance reach the distributor's vacuum advance pot advancing timing above idle and increasing power output.

The electrical plug goes to the frequency valve that may or may not still be on the fuel distributor. It is not really a "solenoid valve" and neither it or it's controller ever goes near any source of vacuum.
A solenoid valve is slow acting and is either open or closed and would over heat and burn out fast if you did open and close it quickly continuously.
A frequency valve opens and closes continuously at a variable high speed making a buzzing sound.
It is an electronic fuel injector with no fuel spray pintle. Instead it has fuel line fittings on both ends so it's an inline electronic fuel injector being used to meter fuel flow through a line and it's called a frequency valve or pulse valve.

The frequency that it opens and closes is controlled by the k-jetronic lambda box or ECU under the driver seat and the lambda ECU uses an oxygen sensor in the exhaust header before the turbo and a temperature sensor in the right side chain case cover as sending units to compute the high speed on/off electrical pulse signals going to the fequency valve.

Now that was a great explanation.

[TDIDog]

I just want to say thanks again to you guys for all your help and explanations. This site is truly an invaluable source of information. I will leave things as they are for now. Car seams to run fine, just won't idle when cold, but fine as it warms up.
Thank you.

[mppickett]

+1

Originally Posted by oilonly

now that was a great explanation.