No, I did not replace the seals. Will this cause issues with the way the car runs? I did notice that some of the holders were starting to crack. I don't have any of the equipment to test the fuel pressure or CO. I guess that I should bit the bullet and take it to a repair shop.

Big time. Dry seals and cracked holders are a major source of vacuum leaks. This will cause the mix to be lean which could explain your idle problems. I recommend replacing the holders and their o-rings, as well as the seals on the injectors.

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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

Thanks, that is too obvious. I will order the parts today, install, and report back with results.

I installed the new holders and seals. It is running much better, the old ones were shot. The cold starting and sluggishness when cold has gotten about 80% better on its own, with FI cleaning, etc. The hot starting issue is still there.

I have an '85 500SEL that has similar symptons.
I seem to be getting closer to isolating the problem.

First, I would try 'simulating' a good WUR.
I did this by placing a 'zip-tie' in the air flow senor opening.
I use a zip tie, because it is flat, and soft (so it won't damage the surface)..
DON'T USE A SCREWDRIVER.
With the tip of the zip tie there, is will enrichen the mixture, simulating what the WUR is supposed to do. See if it starts and idles well at that point. Obviously, don't rev the engine, unless u want to fish the zip tie out of the manifold...

Now, as was mentioned in an earlier post, there is a pressure test procedure that should be done (as soon as I find my pressure tester). This will identify if it is the WUR or the fuel pressure regulator that is bad. The fuel pressure regulator gets its signal from the WUR.

By applying vacuum to one side of the WUR, enrichens the mixture, while vacuum to the other side does the opposite (or at least conteracts the vacuum from the other side). (this would be noted while testing the control pressure). If the pressure does not change, then things are not moving properly in the WUR, it could be clogged or just bad.

If you are having problems starting HOT, it sounds like the pressure is leaking down. This can be verified by trying to manually press down on the air flow plate (with your finger) after 15-20 minutes after the engine has been stopped. The system should retain sufficient static pressure to cause the air plate to push back up.

hope this helps a little...

cory

I wanted to give an update on the thread I started. I have been living with the hot and cold start issues for almost a year and finally took the car to a guy who has worked on Mercedes for 40+ years.
He said that he can't figure out what is wrong with the car. He has tested the CO2 and looked over the car, and drove it. He said that everything looks and tests ok. He did say that I should take the car back to the shop that did the last tune-up because they did a crappy job. But, that was about 10 years ago. He told me it would not be worth throwing money at the car trying to hunt down the problem because it is really just a starting issue.
I am hoping that someone can narrow down what might be wrong with the car based on this. Could I be looking at something as easy as Ignition wires, dist.cap, or a bad coil?

I'd pull the aux air valve, right next to the idle speed screw, and check it. Mine failed open which left me with a wicked fast idle. I pinched the hose with a fuel line pinch off tool to get the idle down and ended up with a cold start issue. Since I knew why, I just let it catch it's breath before taking off.

Cold, the valve should be open and it will begin closing as you heat it. Since it has 30C stamped on it, I assumed it was either to begin closing at 30C or be fully closed at 30C. Anyhow, mine never closed fully. $28 spent at a pick and pull fixed it.

Since it is coolant temp driven, it will dump coolant when you pull it. I just stuffed a rag in for the few minutes I had mine out.

Michael

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Usta haves '69 250/8, '76 280C, 1971 250C 114.023, 1976 450SEL 116.033
Current have, 1983 300SD 126.120

After a year of a crappy running 450sel, I found a new warm-up regulator on ebay for $325. I decided to buy it and see what would happen. She started right up on a 35 degree morning and drives like a new car. Not only does it start great it has twice the pick-up. Thank you for all the input, now I can really injoy this fine automobile.