I think that an '85 would have plain K-Jet rather than KE-Jet injection. So enrichment is controlled by the warm-up regulator, not the actuator controlled by the computer with input from a coolant temp sensor.

Again, I think that your only temp sensor is the one in the back of the right head which tells the idle relay to have more rpm's when the engine is warming up. You might have an oil temp sensor near the filter housing if you have the lambda setup with an O2 sensor and frequency valve. This sensor tells the lambda computer that the engine is warm enough to go into closed loop.

Sorry if this is TMI.

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Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe

Chuck,

If the above is directed to me, I do have a warm-up regulator on the car. Been chasing a stumbling problem for months now and the WUR seems, at this point, to be the cause of the problem. Don't want to hijack this thread, so will post an update on the problem on another thread. Thanks.

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Don
'85 500SL (Euro) - 186,000 w/a complete restoration and engine rebuild at 154,000
'95 C280 - 174,000

BUMP, thanks

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'83 240D (for sale)
'84 Harley FXRT
'85 300CD Turbo (Sold)
'85 500SEC (for sale)
'04 Dodge Dakota Quad
'06 Harley FLHTCI
'97 SL320

Maybe WUR, but the only way to tell is to put a gauge on it and see what system and control pressure are doing.

What do the plugs look like?

You could also be running out of fuel. Suggest a volume test (you should get at least a liter in 30 seconds from the fuel return line, disconnected at the FD.

Maybe you are getting into closed loop and the computer is getting an input that causes it to tell the frequency valve to go lean. That would sort of explain the "switch" symptom. What happens if you unhook the oxygen sensor?

You could also be lean because someone screwed with the mixture. Try going a max 1/2 turn CW in 1/8 increments and see what that does. Be sure to track what you do so you can get back to where it at least starts and sort of runs.

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Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe

Just replaced the top vac hose on the WUR near the 2 elec connections
it was taped & found it severed half way thru.

What would lose of vacumn at this point do to the engine at atartup?
high idle or low?

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83 500 SEC Euro 198K

The vacuum connection on top is a vent and should not be connected anywhere it it's like anything I've ever seen.

On the WUR, you should have a connection on the back that goes to the intake manifold just below the FD via a three-way connector and a temp switch, and one in front that goes to a four-way connector.

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Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe

I'll have to check
but this is the pic & the car is a Euro prod date 5/10/82 but listed A 83

tHERE is a vac hose on top and its listed in 83 500 sec parts manual
also the one in fron & back are alo plain either 45 or 60 vac hoses
no tris coming off

haven't traced them yet but they go under intake manifols area

I do have a 4 way in fron of manifold
have to check thats where it goes

I boutght the 4 way vac hose yesterday
but only got to do the one on top so far

Attached Thumbnails

   

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83 500 SEC Euro 198K

My 84 euro 500sel had an issue w/ starting when warm but started well when cold. And on start up it wouldn't rev up until it ran for at least 10 seconds. Sometimes when hot i'd have to crank on it for at least 5-12 seconds. Quite embarrassing. It also kind of had a lack of power. Goofy me i gambled $100.00 took it to the closest benz dealer and he said fuel accumulator. Well the issue was the fuel accumulator was leaking back fuel pressure into the tank. Thus we weren't getting enough fuel. He temporaryily clamped the hose to the accumulator and it immediately had like another 10 horse and always started up and ran great. So i immediately removed the clamp and put a good accumulator on it. Hope this helps.

Wow!

Didn't notice any power problem but I;m new to the car & used to a 4 cyl.

Starts right up cold
but idles hi 1300 to 1500 until it reaches 80C in park then maybe 800 to 1000

in drive its 650 ish

could that be the accumulatortoo or just the warm/hot start problem
?
Thanks
Have to find it & clamp it.

Would be nice to fix that

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83 500 SEC Euro 198K

A broken vacuum fitting certainly won't help your starting or running. I have no idea what connecting in that top fitting would do, except maybe to increase control pressure, which would lean the mixture in high vacuum situations, like coasting. Where does it connect to the vacuum system?

Another thing to check is to put your Mityvac on all the fittings of the WUR. They should hold vacuum briefly and then slowly lose it. If it's a dead leak, then you need to fix it because not only do you have a vacuum loss, you're not getting any enrichment when you need it.

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Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe

Took the aircleaner off
stiill didn't have access to my vac hoses behind the warm up regulator
I'm very short
I couldn't see behind it & the dist wires were also blocking
but there are at least 5 or 6 back there
one off the back of the WUR
then 4 somehow coming out of something else


So maybe this engine is set up different;y

I took pics to help identify

I did find a hose not attached
bad broken end I cut to expose a good hose & attached it

It was a plastic cann9ister valve connected to a quad in fron that went onto a stem ouut of the manifold...I think

It couldn't have gone anywhere else
& why put a elbow hose on soemthing if it wasn't supposed to go somewhere..

put it back together

Started fine

Think it did run smoother
& started with lower idle 1200 then crept up then down to about 900

Ignition wire boots on distrib cap are shot
I was going to move them to get to the vac hoses better
but saw a break on top
I was afraid if I moved those something might crack so

I'm thinking its beyond me.

I did not see anything that resembles an acumulator

a 82 might not have it

I'll post some pics later maybe someone can figure the setup///

Thanks

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83 500 SEC Euro 198K

pic
green/yellow valve was disonnectedc
I connected it after cuttin goff broken end

I wanted to change those vac hoses behing wur
there is one
I can't get oo it
then there is another 4 or 5
behind a old brittle ing wires I don't want to move

So, don't knoe where to start first

but think car runs better w the new vac hose on top wur & connecting the disconnecter

is the acumlator here?

I didn't see anything that looks like it unser the air assembly

Is the idle control vavle or acululator in these photos?

Thanks

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83 500 SEC Euro 198K

sounds like the piston in the fuel distributor is stuck.[from sitting] buy a new o ring and take off the f.d. clean out with carb cleaner and free up the piston.

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David S Poole
European Performance
Dallas, TX
4696880422

"Fortune favors the prepared mind"
1987 Mercedes Benz 420SEL
1988 Mercedes Benz 300TE (With new evaporator)
2000 Mercedes Benz C280
http://www.w108.org/gallery/albums/A...1159.thumb.jpg

It accelerates smnoothly & has power but
I'll make a note of that since taking off a fuel distributor is beyond the scope of my ability.

Vac lines on this car seem to be different

I have a sec engine part breakdoen & it seemed to be hooked differently...

Don't see those 2 douvle ports coming out of front pass side of engine on intake in any diagrams .


I;ll have to see how it responded to the new vac hose & the reattached one which is bridging a small plastic valve marked pier or something to a vent from intake.

Thanks every bit helps guess the euros do have more problems when it comes to repair

etc finding parts

etc if you look up american specs you don't find the parts on car
I have these

water pump 117 2001 330

dist cap 0290004 505

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83 500 SEC Euro 198K

Found out what the green & yellow plastic valve is a
Air Inject Check Valve

How would it being disconnected affect the engine?

I better get it a new vac hose as its really bad
had to cut the one end straighte agsin as it was all cracked & broken.

Also found reference to a T vac connector to warm up regulator
I have no such.

The Air ICV igoes into the intake man
but is also connected to a 4 way & where they do is not clear

Thanks

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83 500 SEC Euro 198K