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Frequency valve not buzzing 83'SC
Should jumping the terminals at the Lambda relay plug below give me 12 volts at the frequency valve connection?
It doesn't. Am I missing something? ![]()
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-Vinny 1983 911SC |
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bump.
JW? Warren?
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-Vinny 1983 911SC |
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Somatic Negative Optimist
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I seem to recall that the interior light fuse has something to do with powering the frequency valve.
Is your interior light working?
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1980 Carrerarized SC with SS 3.2, LSD & Extras. SOLD! 1995 seafoam-green 993 C2, LSD, Sport seats. ![]() Abstract Darwin Ipso Facto: "Life is evolutionary random and has no meaning as evidenced by 7 Billion paranoid talking monkeys with super-inflated egos and matching vanity worshipping illusionary Gods and Saviors ". ![]() |
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Yes , they work
5amp fuse for dome lights is good
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-Vinny 1983 911SC |
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Connector in the picture is where the relay plugs into.
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-Vinny 1983 911SC |
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Quote:
If it's the freq valve, PM me I have one you can have for the cost of shipping.
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2021 Model Y 2005 Cayenne Turbo 2012 Panamera 4S 1980 911 SC 1999 996 Cab |
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Thanks Scott. At this point I think problem should be something other than the frequency valve as I'm not getting power at the FV connector in the engine compartment (Lambda Brain?).
As a bit of added info I am doing this with engine running and I have juice at the connector.
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-Vinny 1983 911SC |
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2021 Model Y 2005 Cayenne Turbo 2012 Panamera 4S 1980 911 SC 1999 996 Cab |
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minor screw up..
I in fact do have about 8.5 volts going to one pin at the frequency valve connection, I put the other pin to ground- should have thought to do this yesterday.
so- OK, it seems the Lambda brain may not be giving a ground to the other pin that would operate the frequency valve. but- Is the FV doing what it's supposed to be doing when powered up? I made a test connection shown here in the picture. When I put 12v to the FV all I get is one solid "click" nothing more. No buzzing/vibrating what-so-ever. ![]() Is it a rapid "on and off" ground from the Lambda box that creates the normal buzzing or is there something wrong with my FV? Can someone confirm this? Scott- should I take you up on your generous offer? Thanks Vinny
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-Vinny 1983 911SC |
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the computer fluctuates the ground pulse, faster or slower, depending on info from the oxy sensor. if the sensor is unplugged, it still pulses, but the pulse doesn't vary. remove the computer, pull the cover and check for water damage or check all the solder connections with a magnifying glass. broken solder joints often show a crack as a circle in the joint.
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https://www.instagram.com/johnwalker8704 8009 103rd pl ne Marysville Wa 98270 206 637 4071 |
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2021 Model Y 2005 Cayenne Turbo 2012 Panamera 4S 1980 911 SC 1999 996 Cab |
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Thanks guys.
Looking at this, nothing is jumping out at me. Does this look water damaged? ![]() ![]()
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-Vinny 1983 911SC |
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Is there a schematic of the circuit board of this componant anywhere online?
I have an electrical engineer at work I could have look at it
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-Vinny 1983 911SC |
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Do a Google or a Yahoo search for "Lambda Control Unit".
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Have Fun Loren Systems Consulting Automotive Electronics '88 911 3.2 '04 GSXR1000 '01 Ducati 996 '03 BMW BCR - Gone |
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Could the problem lie in the enrichment relay with the round plug that sits next to the Lambda brain?
If so how can I single out which componant is the problem? I have stared at the circuit board of the Lambda brain for quite a while and see no broken solder joints.
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-Vinny 1983 911SC |
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2021 Model Y 2005 Cayenne Turbo 2012 Panamera 4S 1980 911 SC 1999 996 Cab |
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I have not checked with a meter but car races when cold so I would say yes I do.
I have looked online at what these broken solder joints look like and can honestly say I see nothing like those examples. Should I get a hold of a microscope?
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-Vinny 1983 911SC |
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update
I just swapped a known working Lambda brain into the car with absolutely no change. O2 sensor plugged in or not makes no difference I still have 8.5 volts at one of the terminals at the frequency valve. Not sure where to go from here I connected a fuel injector pulse tester like the one shown below ![]() With this thing plugged in the car runs GREAT. Runs smooth with lots of power. The terminal at this tool is about 12 volts and give the FV a very audible buzzing sound with vibration I could really feel. Should I have a full 12 volts at the FV? Could this be the problem?
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-Vinny 1983 911SC |
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I'm not sure what it's supposed to be, I mean it's 12V but the ground is fluctuated to pulse the injector. It's not a constant 12 however. If I still had CIS I would be putting a meter on there right now for you. All that aside, why not try an run a temporary line from the corresponding pins in the diagram to get around any electrical connection issues?
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Hiya Scott
When I checked the voltage at the FV connector I am taking the pulsed ground out of the loop - correct? In other words I put one probe of my meter to one of the FV connector's terminal and the other grounded right to the engine. This is where I am getting the 8.5 volts. Like you said about a temporary line going around wiring issues. I'm thinking running a long wire from terminal 87b at the relay under the seat straight to the FV to see if I get anything greater than the 8.5. I'm not sure what the voltage should be either.
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-Vinny 1983 911SC |
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