lambda system not working...lean running

[jim tulloch]

My Lambda system is not working, frequency valve not vibrating and there is no signal at the diagnostic port using a dwell meter. So, i need to determine continuity of wires and identify what is not working. I need a wiring diagram showing the connections at the 'computer" under the seat and what each is for. Second, if a frequency valve is not working does it "close " so no fuel gets by? That seems to be what is happening. If it is bad, who has them for sale? I think I need to get this system functioning..there appears no other solution. Right?
Any guidance would be most appreciated. Thanks jim

[mark houghton]

If you can't get it working, and don't care about the lambda circuit for emissions reasons, then the fuel distributor can be "tweaked" to run with all the lambda stuff bypassed. I can't give you an detail on how to do it, but best left to a professional shop that can. I once unplugged my freq valve just for kicks, and she ran super lean per my AFR gauge, and I could not get it back in the correct range with adjusting the mixture control alone. Mr. Fairman may be able to give more concise advice if he's listening today.

[jim tulloch]

Thanks Mark, i appreciat ethe input. I would prefer not to compensate for the lambda system but also realize how much i do not know anything but how it works. I really need wiring diagrams, thoughts about how to check out the system. I have verified today the frequency valve is not receiving a signal so the frequency valve may be working. Thanks again, jim

[Speedy Squirrel]

This is a big diagram, and it involves the Lambda controller, the speed relay, the thermo switches, the throttle switches, and the PWM solenoid. You are going to need a multimeter, and preferably one that can read duty cycle. The wiring diagram contains minimal hints as to how it all works.

So, do you still want it?

[jim tulloch]

Hi SS....yes I do! I have seen elements of the diagram but not in it’s entirity. Understanding how each component influences the others will take some time but I have to start somewhere. Thanks, jim

[Speedy Squirrel]

Well, that kind of courage deserves some support.

Originally Posted by jim tulloch

Hi SS....yes I do! I have seen elements of the diagram but not in it’s entirity. Understanding how each component influences the others will take some time but I have to start somewhere. Thanks, jim

[jim tulloch]

Thank you.... Wow! Jim

[T77911S]

the FV gets its power from the o2 rly under the seat.
that rly is energized by FP rly 2.. just another thing loaded on the FP circuit.

you can try to resolder the connections on the O2 rly.
you can also check the fuse for the O2 rly. don't know which one but it is fuse 18 for a 911.
start with the fuse first.

[jim tulloch]

Thanks for the O2 power supply relay info. Good advice. When i look under the seat I see three units, the oxygen sensor control unit, the speed relay and the fuel enrichment control unit. I see no other relay. On the wiring diagram the O2 power supply relay with the traditional numbered (86,30,86,85) connections. Where is the relay? What am I missing? Thanks, jim

[T77911S]

I think it is back on the relay panel in the engine bay.

my lambda has all been removed

[flightlead404]

The other option is to install a WBO2 sensor and go FrankenCIS