82 380SL Frequency valve BUZZING! Among other things!
 

I was told you can clean these things...can anyone tell me how? :confused: When I turn on key the FV buzzes and VIBRATES YIKES! :eek:Car just quit on the road...fuel getting to F Dist. The buzzing from the FV and fuel pump is annoying. The buzzing from the fuel pump has changed in pitch. Sounds like it is...dry??
Did Einstein help build these things, because all I have found All things are relative .
STILL love this car....

dont think the Kjet pumps can be overhauled

Frequency valve
 

this little yellow thing with an electrical plug and a piece of fuel line on one end..I was told it deals with fuel/air ratio..AND that it can be cleaned..well it VIBRATES LIKE CRAZY! I know I wandered around a bit with the original post, but was wondering if there was anything I can do to this before I just buy another one..hubby seems to think it will cure all ills...if only THAT were true..!;)

still not sure what you are talking about, can you snap a picture. I was referring to the Kjet fuel pump

Frequency valve photo
 

http://thumbs3.ebaystatic.com/pict/1...46506464_2.jpgLocated on top driverside next to air cleaner body.

First... sorry for my poor "technical" english (I'm from sweden)
I see you mentioned frequency valve on here...
I also have a possible problem with this, I have just bought a 280 SL -85 in Germany, drove it home a couple of days ago. Wen I came home I noticed that all spark plugs are black and fouled. When the car idles the ground behind the exhaust pipes get fouled and black. But except for this there isn't any starting or idling problem. I've read that the frequency valve is controlled by the oxygen sensor and regulates the fuel/air mixture which i my case could cause a rich mixture if the sensor or valve are broken.

Everyone talks about that the WUR can cause to rich mixture but it looks like the FV replaced the WUR(cant find any WUR on my car)... Am I right? Just trying to understand how my system works

gotcha, yes they can be refurbished , but not on a home bench unless you have the correct set up
call these guys
http://www.witchhunter.com/ perhaps they could help , not sure

I finally found the WUR... mounted on the motor at cyl 6... below the intake manifold... followed the fuel line to find it... I will tyr to remove so I can measure the warmup-coil...

I have bought a multimeter to check the duty cycle on the Frequency valve via the diagnosic plug. I cant hear or feal anything on the frequency valve thats why I will check this first.

When I turn on the ignition, the fuel pump make a ticking/buzzing sound which doesn't stop, not like anything is broken but there is a buzzing sound from it. Usally on modern car you can hear the pump but it stops when the fuel pressure are up.

Do you think there could be a problem with the pump also?

my pump buzzes all the time, most do

Have dig some deeper into my problem with rich mixture...

When I mesure pin 3/6 at the diagnostic plug it shows 0%, I've bought a duty cycle meter just for this, connected some cords from the the plug into the cupe so I could see the value while driving (0%) http://www.benzworld.org/forums/imag...lies/frown.gif , should alternate between 40 to 70 % (at least show something).

Does anyone know the oxygene sensors part number, because I think I start replacing it first since I dont get any signal at all.
I did check all cables, even found the "lambda ECU" but everything looks fine.

I could also need the part number for the WUR, I dont know if its expensive but I think I will replace it anyway.

The motor is a M110.989

kind regards Peter

Propably cost more to send it to sweden then buying one here, but thanks anyway...
I will measure the voltage from the oxygene sensor tomorrow and see if it's ok. Should be around 0.5V if its ok, otherwise I buy a new one to start with since it's obviulsy something wrong with the lamda-control.
THe next step will be to check the WUR...
kind regards Peter

About the O2 sensor....when you check it...
 

I ran into this problem.. the o2 sensor read 0.23 with indicated that it was not working at all. it just stuck there. I change it and went to .34 which is still not working right.
when I replaced the sensor, I changed the plug coming from the lambda to match the single wire flat blade connector on the sensor. the old connector just fell off in my hand when I touched it!
Well i crimped another one on real good thinkin I did something great only to discover that the green wire coming from Lambda has a grounded shield under the green insulation THEN a thin single wire for the o2 sensor! i connected the shield and the single wire together when i crimped it, JUST LIKE THE OTHER ONE WAS! Well, I just grounded out the sensor and it also read .34 when tested! DUH can you say DOUBLE DUH! I removed the crimp, trimmed back the copper braid ground and reconnected the single wire to o2 sensor. BAZZINGA a better reading!:thumbsup:

Did some tests today and result doesn't say much...

Ignition on...
Mesured between the 2 with cables wich should be the heating and it says 12V so this seems ok.

Mesured the Black cable wich should be the lambda signal and it shows 0.9V (cold motor). Took it for a drive and mesured the signal when the motor was warm, it still says 0.9V. checked the voltage at different rpm and I can se the voltage changing a little but still around 0.9V.

I then disconnected the Lambda and then the Frequency valve started to tick wich it doesn't do when the lamda sensor is connected, should indicate that the valve is ok. Took the car for a drive without the lambda connected which didn't go well, black smoke and very poor accelaration, had to stop and connect it again.

So whats the conclusion here!
Frequency valve is OK since it ticks when lambda sensor is disconnected.
Is the mixture so high because of other reasons and therfore the lambda sensor indicates 0.9V and closes the Frequency valve (no ticking), sure looks like it.

I will do a quick and dirty fix... I will squeese the Frequency valves rubber fuel line so that no fuel can go that way, this way should be able to exclude any impact from the lambda system.
Then start checking the fuel pressure to see if it can be the WUR.

I have also disconnected the start injector's termoswith so I can be sure that this isn't on all the time.

kind regards Peter

Obviously, if you are getting .9V out of your oxygen sensor you are very rich. The poor lambda system is working overtime to lower it. This can be caused by:

- leaking cold start valve or malfunctioning thermo-time switch. Take the valve out and reconnect it. Plug the hole, point it into a container, start the engine and observe how long it squirts fuel. It should not be more than a second or two with a cold engine.

- a bad WUR, although this will normally cause lean running. This would show up as low control pressure.

- high system pressure, possibly caused by a blocked return line.

- a misadjusted base mixture. Try putting a 3 mm hex key through the hole in the top of the fuel distributor. Turn it slowly and press it down lightly to engage the adjuster, then press down and try going counter-clockwise 1/8 turn at a time to lean the mixture. Keep track of where you are at all times and give the systm at least 15 seconds to stabillize after each 1/8 turn.

Exactly what I'm trying to do...

I have checked the Cold start valve and it's only opened for 2 sec...
I connected a 12V lamp-bulb on the plug when checking so I hope the valve itself isn't leaking. Maby I should take the valve out, just to be sure...

I'm building a T-connector right now so I can measure the fuel pressuer from the WUR and the system pressure. So I will check the pressure as soon as I get the things together. Doesn't want to touch anything until I know if the WUR is OK since it seems to be the usual problem.

If the WUR is broken I'm thinking of buying a "UTCIS-V" which replaces the Bosch WUR but how much does it cost, cant find any price.

kind regards Peter