Help with lambda/freq valve test please

[gazzerr]

Thanks Bob and blpetry.

Bob thanks for confirming. I'm going to chase the vacuum leaks a little more like you said. I think the PO was definitely messing with the mixture to tune out the vacuum leaks because the shear off screw in the top of the fuel distributer has been removed.

[blpetry]

Went out and tried my trusty actron meter again tonight. Hooked it up immediately before performing a cold start (open loop, cold engine, O2 not functioning yet) and it went to 10 degrees and pretty much stayed there like I remembered. The meter is not defective as I use it often to set the mixture on my 84 vw gti, which has an almost identical (albeit smaller) CIS system and the mixture is set exactly the same way.

If you hook the dwell meter up and it doesn't go to 22.5 degrees or higher on cold start open loop operation, it isn't reading correctly. You can also force the open loop by disconnecting the O2 sensor, but be careful with the connector in the engine compartment, they are prone to breakage.

Since the exact same meter is proven to work properly on Bob's car, and the parts catalog does show that there was a change to the brain box around 81, I'm wondering if we're looking at different signals. I'd be interested to see what Bob's signal looks like on a scope.

I think a good next step for the OP would be to try the duty cycle on your multimeter and see what it tells you.

[Westy]

Can I hijack this this thread a little. Having similar probs and trying to get the car smogged. Is this the FV to my 81 SC?? If not, what is it?






I'm confused, 'cause Pelican's schematic would suggest no, but Vertec and others show something similar to this.

[gazzerr]

Thanks blperty. My car was hot when I hooked mine up. I think you are right when you say the guts of the Actron have changed. I was wondering what model Bob has. I'll try again cold when I get a chance. And yes I'm paranoid about that O2 connector! Mine seems in good shape so I'm gun shy to mess with it.

Westy - I *think* that might be the cold start injector that mounts on the back of the CIS airbox. I've never removed mine so I'm not 100% sure but the electrical connector and mounting block before the actual injector there sure looks like it. I'll take a look at the PET.

[gazzerr]

Yeah here you go - cold start valve:

1982 Porsche 911 SC Targa - Fuel Injection - Page 1

[Bob Kontak]

That is the cold start valve. It is very close to the frequency valve location wise. The frequency valve does not spray it chokes or unchokes pressure in the "control pressure" line that changes the pressure in the lower half of the fuel distributor allowing it to piss out more or less fuel to the injectors.

[Bob Kontak]

Originally Posted by gazzerr

I was wondering what model Bob has.

CP7605 Sorry for delay.

[gazzerr]

No worries thanks!

[Bob Kontak]

Originally Posted by blpetry

If you hook the dwell meter up and it doesn't go to 22.5 degrees or higher on cold start open loop operation, it isn't reading correctly.

+1. Yes, it goes to like 60 on the 4 cyl scale. Valid point.

Mine is stone cold. I will check in a few.

[Westy]

Thanx guys. That valve clicks just fine. Guess what apparently doesn't? Yup, FV. At $560 bucks for a FV, me thinks I'll have to find another avenue! Maybe one from from a Mercedes or BMW!!!!!

[Bob Kontak]

Originally Posted by Westy

At $560 bucks for a FV, me thinks I'll have to find another avenue!

Frequency valve, working fine it is, young Skywalker.

You buy anything and the fat man cuts you. You have a signal delivery issue.

[Westy]

Originally Posted by Bob Kontak

Frequency valve, working fine it is, young Skywalker.

You buy anything and the fat man cuts you. You have a signal delivery issue.

Have been nippin' at the bottle again? You are not Fecklar! Hmmm???

The plug for the FV has appropriate power. My guy says he put a stethoscope on the FV and it just weren't clickin' away. This is all to pass smog so when I sell it I can include potential CA buyers. With the coin that's gone into it, I might drive it til next spring and sell it then. Hate to pay and not play at least a little.

[Bob Kontak]

Originally Posted by Westy

Have been nippin' at the bottle again?

Hell yes, I been nippin'.

Lemmie do the setup for the plpetry thing. Cold start with Lambda - high duty cycle check.

So what you are saying is that there is voltage to the freq valve? Appropriate power is confirmed? What I don't know is what type of signal comes from the lambda box to the freq valve. There is some kind of voltage, but it cannot be a constant 12V. It has to vary given it feeds duty cycle.

FWIW - freq valve does not click, it buzzes. But if there is nuttin, there is nuttin.

[Bob Kontak]

Originally Posted by Westy

You are not Fecklar! Hmmm???

I have my ego defined through a fully separate imaginary creature.

[Westy]

I didn't write down the number, but IIRC he said a low of somewhere around 6v and a high of 11 point sompin or other. Lambda was replaced a few years back. He!!,,,almost everything has been replaced in the last few years. Makes wanna go down and work on my Camaro. THAT I understand!!!

[Westy]

Now ur gonna say Fecklar is imaginary. Oh sure, whatever you say boss!!!

[Bob Kontak]

Originally Posted by Westy

but IIRC he said a low of somewhere around 6v and a high of 11 point sompin or other.

Ok - that makes some sense. FV has to be fed with something. It's a 12V car. What else can it send? Voltage is pretty much it.

[Bob Kontak]

Originally Posted by Westy

Now ur gonna say Fecklar is imaginary. Oh sure, whatever you say boss!!!

Bwa ha ha ha. Doing searches on Fecklar. Give an old man a chance.

Cripes - Why did you make me look up 73RS Z28. So beautiful. So simple. So powerful. I had a 69 Opel GT in 73.

Let's not discuss.

[gazzerr]

I'll try the cold start open loop on mine ASAP and report back.

Yeah I love my 911's flat six but I don't mind a good old fashioned V8 either .

[Bob Kontak]

Originally Posted by gazzerr

I'll try the cold start open loop on mine ASAP and report back.

Yeah I love my 911's flat six but I don't mind a good old fashioned V8 either .

Just performed test - mind you this is on my car - not indicative of the population.

Went right to 22 on the 8 cyl scale. Was looking for more. Steady as a rock. Touched throttle linkage, I mean touched, pressure - not movement - went to 35.

I got my own issues.