Relay under passenger seat clicking

Lundegaard · 06-05-2018, 08:21 AM

Unpluged the lamba when the engine was running, because i schould set the mixture.
After i set the mixture i turned off the engine and pluged the lamba again, but now i have a clicking from the small relay under the passangerseat, but only at idle 950rpm. When i rice the idle above 1200rpm the clicking stops....????

Lundegaard · 06-05-2018, 10:34 AM

Forgot to mention that i adjustet the mixture by lifting the air censor plate until it dident increase in rpm. The mixture was way to lean so i increased the mixture a lot by turning the mixture screw clockwise. At the same time i adjustet the idle screw to lower rpm, because the idel turned up every time i increased the mixture. The idle screw i turned all way in now, and the idle sits at 950rpm, and the motor runs mutch better.
But the relay is clicking now????

Bob Kontak · Bob Kontak's Garage

Quote:

Originally Posted by Lundegaard

The idle screw i turned all way in now, and the idle sits at 950rpm, and the motor runs mutch better.

If the car runs at 950 rpm with the idle air bypass screw turned all the way in you have air leaks that are causing your mixture to be lean. By shutting off the air bypass you have reduced the impact of the leaks.

You engine should stall or run poorly at 200rpm with the screw all the way in.

Clicking - are you certain it is the relay that is clicking? I don't think the relay should click. It only supplies power. Maybe it is near the end of it's life?

The more you talk about what you did the more people can help you.

Where are you located?

Lundegaard · 06-05-2018, 12:38 PM

The relay was not clicking before i adjusted the misture, and yes i am sure that it is the relay. I can hear it very eazy and i can also feel it is clicking when i touch it.
I think i will try to lean the mixture a bit by turning the mixture screw anti clockwise, then the rpm should also go down, and then open the idle screw to increase the rpm. Hopfuly the relay will stop clicking.

Bob Kontak · Bob Kontak's Garage

The feel test confirms it. Thanks.

I do not believe the relay should ever click except when engaged initially. I have not looked at the wiring for the relay for a long while.

There is always power going to this relay but it's the lambda system power. There is a separate power source to engage the electro-magnet inside the relay allowing power to reach the frequency valve once the engine is started.

What I am thinking is that your relay is tired or at 950 RPM your alternator may be creating a lower voltage than required to keep the relay electro-magnet engaged. As you increase RPM the alternator my create more voltage allowing it to remain engaged.

Perhaps corrosion on the relay pins. Remove and re-install a few times to clean off contacts.

RDM · RDM's Garage

Bob,

Doesn't the relay turn the frequency valve on and off?

Lundegaard · 06-06-2018, 06:43 AM

It is not the altenator, it has been running lover in rpm without the relay clicking.
But has just tryed to lean the mixture by turning the mixture screw anti clockvise( about 1/4 turn) the idle went about 50-100 rpm down and then open the idle screw a bit then the relay stopet clicking, but then my idlerpm is to hiegh, about 1100. And if i turn the idle screw to get i down to 950 rpm it is all the way it can get, then the relay starts clicking again.
Can it has somthing with my throttle valve posisition to do?

Lundegaard · 06-06-2018, 06:51 AM

Have tryed to pull out the relay under the seat, and the motor startet to run very bad, so sure that the relay sends power to the frequency valve��

SCadaddle · 06-06-2018, 07:06 AM

My understanding as a do it yourself'er and NOT a mechanic that makes a living fixing these old cars, at least when it comes to my 1982 911SC North America variant with the Lamda system and catalytic converter, is that you set the idle mixture with the oxygen sensor unplugged at the catalytic converter in the engine compartment. The relay under the passenger seat next to the Lamda control box should get power when the car starts. With the oxygen sensor unplugged in the rear of the car you then set the mixture while the Lamda system is in "open loop" mode i.e. not getting any mixture correction signal from the control box via the oxygen sensor. Once that is correct, you then reconnect the oxygen sensor wiring in the rear of the car and the system goes into "closed loop" and the oxygen sensor sends its signal for the Lamda control box to vary the mixture as needed. Am I wrong?

So here is a test you could probably do to see if you have an intermittent electrical circuit to the relay at the Lamda control box that is making it click: Turn on the passengers side overhead light in the headliner and see if it is flickering when the relay is clicking. They are on the same circuit on the cars over here in the USA.

Bob Kontak · Bob Kontak's Garage

Quote:

Originally Posted by RDM

Bob,

Doesn't the relay turn the frequency valve on and off?

Yes. If you jumper-wire two of the pins you can get the frequency valve to engage without the car running.

I just don't remember which ones. I did help a guy test his a few years back. Let me see if I can find that thread.

Pazuzu · 06-06-2018, 09:08 AM

If you unplugged the relay, then you disabled the frequency valve. You then tested the exhaust and found it very lean. That's because the lambda CIS uses the frequency valve as a major source of fuel all of the time. It doesn't just regulate the air fuel mixture, it's a pretty significant fraction of the total fuel needed.

You set your engine up WAYYYY to rich now. I bet that the Lambda computer is reading it so rich, that it's running the relay at a very low duty cycle, which is pretty weird for it...low enough that you can hear the cycling.

Bob Kontak · Bob Kontak's Garage

Quote:

Originally Posted by Pazuzu

You set your engine up WAYYYY to rich now. I bet that the Lambda computer is reading it so rich, that it's running the relay at a very low duty cycle, which is pretty weird for it...low enough that you can hear the cycling.

Betting vacuum leaks offset by very rich mixture. (which deserves a big no kidding response)

Car should stall if idle bypass screw is turned all the way in.

Find leaks and start to bring it back to a better AF ratio with 3mm wrench.

Lundegaard · 06-07-2018, 03:41 AM

Thanks for all the feedback.
It is starting to make sense, i also think it is a vacuum leak. I work in the windturbine industri, so i have vacuum pump and vacuum leak finder at my work. I will try to connect the wacuum pump, but where is the best place to connect a tube? When the pump is connected the right place, i have this tool that can hear almost nothing that is leaking, so hopfully i can find it that way.
I also need to close the exhaust outlet right?
I do not hope that i can destroy anything this way?

Bob Kontak · Bob Kontak's Garage

There two vacuum ports on the rear bumper side of the engine (the easy side) attached to the throttle body.

Access is not easy but they are near where the air box is closest to the throttle body upper left hand side.

Lundegaard · 06-08-2018, 11:25 AM

Juhuuu.. Did the vacumpump test today, and found a leak where the pop off valve is glued. I used the vacuum leak finder, and it diddent take long before i found it. I also checked the injectors for leaks but coulden't hear anything. Then i adjusted the mixture by lifting the the air censor plate until the rpm didn't increase, at the same time i adjusted the idle screw, so now my engine is running perfekt and stable at 900-950rpm. I'm Happy��