So my frequency valve is not working
 

1982 911

What to check for first?

What causes the frequency valve to not kick on other than the oxygen sensor relay?

I have a new relay on order from our host but it will not arive until next week I was wondering what else I can check.
thank you

fuse 18

Ok checked fuse 18 still nothing

Anyone

it could be the ECU too. I just went thru this with my newly acquired 83.. Both the ECU and relay wasn't working. Chances are that it is the relay only.

Could be the oxygen sensor itself. The FV might be actually working but the duty cycle is so low you can't hear it. I'd check that the sensor is actually plugged in and working. My FV was not audible until I changed out the old oxygen sensor, then I could hear the FV working away.

There is a way you can cheat the system and test freq valve with key off. You have to jumper the relay ports with a wire. Let me find the correct post and will link it in an edit in this post.

Here is the link. See post 13. I was on the phone with the original poster of this thread when he got it working using this method. Let me pull the test on my car right now so you don't screw something up based on my recommendation.

http://forums.pelicanparts.com/porsche-911-technical-forum/559200-911-sc-running-flat-no-idle.html

Dave i tryed calling you but your phone was off. Give me a call at your convenience thanks

Yea im thinking it may be my ecu because my old relay is clicking but fv still not running.

Could the relay be bad but still click when i plug it into the running car??

By the way symptoms are rough idel backfires will not rev up spits and sputters.
thanks

it could be the ECU too. I just went thru this with my newly acquired 83.. Both the ECU and relay wasn't working. Chances are that it is the relay only.

i sent you a pm. i am away until july 14th.

You can't be sure right now. You can have a perfect relay and a perfect ECU and the 12 pin connector by the driver's rear shock could have a corroded connector not allowing voltage to your freq valve.

Can click all day.

Still working on confirming this mentioned test for you.

These are your symptoms, correct? I pull the relay at 23 seconds in.

<iframe width="420" height="315" src="https://www.youtube.com/embed/5tdpCYyvqSc" frameborder="0" allowfullscreen></iframe>

Yes my syptoms, however my car may be backfiring more as soon as i touch the throttle

I had the cover on the air intake and the camera does not really pick up the "pop' very well.

Confirmed test. Taking some pics so you can perform if you choose.

Ok thanks bob much appreciated and ill check the 12 pin connector too

The top two middle connectors are the two 87's. The bottom middle is the 30.

Flankers are not necessary for test.

Wire the base of these three prongs together (A PITA) and plug in.

Preferably if you can use a wire like I crafted and plug them into the corresponding female ports on the wire loom that will send 12V to the freq valve.

You cannot hear it run when under the passenger seat. You can hear it run through the engine grill.

Good luck. Worked for me just now.

If nothing, then more digging.

http://forums.pelicanparts.com/uploa...1434663782.jpg

Don't do that now as it is pain (the connector itself). Your relay may just be tired or cooked.

This will absolutely confirm that juice is or is not getting to the freq valve. If it confirms, screw the extra work.

Well, it can confirm that freq valve is toast but that is VERY rare.

If you end up needing an ECU let me know. I've got one avail for 80-83 sc cars. I bought it from a pelican recently to help diagnose if mine was bad and it turned out to be an entirely different problem so now ive got a spare ECU. Tim

Ok just so im understanding correctly wrap the three said prongs together and run three wires to the corsponding female ports and this should kick on the fv while key is on?

Thanks tkmoore ill keep you posted

No - one or the other. Do the tri wire plug in. Not the three prongs. You want a pic of it in the female plug in port? Let me do that for you.

Removes all doubt. Back in a few.

Connect all three center ones together. Two flats (87's) and the vertical (30) with the wire. That's it.

Freq will run if all else ok. Betcha it does. Listen near engine.

http://forums.pelicanparts.com/uploa...1434666013.jpg

Gotcha bob thank you ill try it tonight when i get off.

TMI, Broseph. Your sex life is your business.:D

lol

Ok tried the jumper and .... nothing this was with key on the on position engine not running.

Key on, key off. No matter. The O2/lambda circuit is live all the time.

You sent juice directly to the freq valve. It did not energize.

Now you have to confirm the valve is dead or there is a circuit interruption.

This has nothing to do with the Lambda box (at this point). Meaning this does not confirm the box is or is not working.

Now you can sniff at that 12 pin. Harbor freight sells a pretty good multi meter in the low $20 range if you are not a tool fancy pants. Gonna need that.

Couldn't i just pull the wire connection at valve and test it with meter to see if im getting power?

Yes you can. It is one of those wire fastener jobbies like on top of the warm up regulator.

Kind of a pain to get that wire off but very do-able. You don't really have to see it. Just understand where the spring wire ends are and use the right tool to dislodge it.

It is the correct place to start.

Ok thanks for all the help much appreciated ill report back tomorrow

No power at fv conector

Cancel that ,

Ok so no power at fv with oxs relay installed.

POWER at fv with wire jumper installed in oxs relay port. But fv still will not kick on does this make any sense?

By the way, when was the last time it was working? Not trying to be silly, but that could be very helpful when trying to diagnose a problem such as this.

Let me think on that. What I don't fully understand is what happens with the other wire. It goes back to the Lambda box and I have a feeling it provides the ground for the f valve. I probably flashes the ground on and off for differences in fuel pressure.

Let me research.

For grins, see if you can take the other connector and establish ground with the engine case.

Both of the wires go through the 12 pin connector.

Terminal #2 (power) and Terminal #1 (back to Lambda Box).

The 12 pin has the little numbers cast into it.

It worked fine last week then twice it spit and spudderd so i shut it off.. restarted to no idle and backfiring

Why am i getting power to the fv with the jumper and not the relay but still will not turn on the fv?

Could it be the ecu lambda box?

The answer to your first question is that you jump the relay for a reason. Power does not go to the fv unless a couple of things happen. Key in on position AND you lift the air sensor allowing the switch on the back of the air meter unit to engage allowing the relay to work and send juice via one of the 87 terminals on the relay. Cheater wire bypasses that. Takes fused battery power and sends it to the fv. The loop must be completed though, just like the a light bulb needs power on one connector and a ground on the other.

2nd question. You have power on one side of the connector with the cheater wire in. Does the other side provide a ground - one lead to the other connector the other lead to the engine case with a resistance test (ohms)? Check this using the ohms function on the multi meter. If you don't know how to do this it is perfectly ok. I will tell you.

No ground - no fv run. Ground may be interrupted at the 12 pin connector or by the Lambda box being faulty OR the FV being bad and ground then is meaningless.

Ok i tryed checking ohms on the other side but not sure im doing it correctly also pulled 12 pin and took a pic someone else has been there and looks like broke it and put in a jumper see photo.
http://i1211.photobucket.com/albums/...psuvexmimo.jpghttp://i1211.photobucket.com/albums/...pstf1wl9yn.jpg

Oh, Man. Good job. This may or may not be an issue. However, when you find something like this it raises and eyebrow.

If you have a multi-meter, tell me what kind. If it is the "free" harbor freight kind, go there again and spring for the miraculously on sale again, #37772 multi meter. - $23.99 - it is well worth that amount.

It will pull you out of this.

If you have a rdecent multi meter, then advise and I will set you straight. This is now a pretty straight-forward exercise if you have the right info.

I have a junk craftsman meeterhttp://i1211.photobucket.com/albums/...psfopghtck.jpg