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JFairman JFairman is offline
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Join Date: Jul 2006
Location: S. Florida
Posts: 7,289
"I have filled in a few more gaps, but still unclear about Throttle Bypass Valve (row 32). Can someone confirm that this is also known as AAR (row 8)?"

Technically there are only 2 throttle bypass valves on 930 CIS: The cold start AAR that bypasses air around the throttle body to raise idle speed when the motor is cold, and the deceleration valve which bypasses air around the throttle body butterfly during decleration and intake manifold vacuum is higher than 20 inches of mercury. It is sometimes referred to as a vacuum limiter.

The AAR has a 12 volt heater element on it's bimetalic spring just like the WUR and they are wired in parallel and mounted next to each other. It is the one in the electrical diagram you posted and you can see it's heater element wired in parallel with the WUR heater element in the diagram.
The 12v power to them comes from the rear fuel pump relay so if the rear fuel pump is running they are heating up.

The decleration valve is opened only by intake manifold vacuum and it bypasses some air around the throttle body when the butterfly is closed during higher rpm deceleration and intake manifold vacuum raises above 20-21 inches of mercury. It is closed at idle speed when working properly and manifold vacuum is only around 11-13 inches of mercury in a 930. Idle speed vacuum is alot lower than normally aspirated motors because the low 7:1 compression ratio which is very inefficiant when the motor has to suck in it's own air.

The deceleration valve is an emmision control device that lowers NO2 and hydrocarbon exhaust emissions during deceleration and it works at the same time the blow off valve operates and it opens at a little higher intake manifold vacuum than the blow off valve when working properly.
It also reduces turbo compressor surge in tandem with the blow off valve during deceleration to a small degree.

Your '86 930 came with a yellow relay onb the rear panel. They all did in the eightee's or at least all the USA cars did.
If it's gone somebody removed it and stuck a black relay in it's socket. My '87 won't run with a black or red relay in place of the yellow relay but one will work there in some of the older cars so I don't know whats happening with yours.

All USA 930's from '86 on are lambda equipped with an air pump and catalytic converter and they all have a black relay on the rear panel to supply 12 volts to the heater element in the lambda oxygen sensor. If it's not there it's been removed on your car or maybe you're mistaking one for the other.
The empty relay socket that only has female 2 pins and is mounted sideways on the back of the relay panel is for connectiong an oscilliscope type meter to check the lambda pulse valve frequency/dwell time.

hope that helps.
Old 01-18-2012, 07:14 AM
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