rev9k

I was running into problems where the car would cruise along just fine and feel like it was hesitating. I would floor the accelerator and it would jump to life. this was very intermittent.
Until one day when it actually started running rough like that and then died in an intersection.
The car would crank and fire once and then just keep cranking.
I had it towed back to the house.
Further testing revealed that if I started it and kept the RPM's up past 5000 it would run great. As soon as I let the RPM's drop below around 3000 it would die.
I read on here that the cold start valve could cause this but I also did read another thrread that a faulty O2 could cuase this. I have a O2 code already thrown. I thought that the ECU would just run in OPEN mode once the O2 sensor has been faulted.
I unplugged my O2 and no change. Runs for about a sec and a half and then just dies. If I floor it, it keeps running as long as I keep the RPM's up above 3K.
Unplugging the electrical lead to the Cold Start valve resulted in NO Start whatsoever.
I looked around quite a bit for vacuum leaks, but couldn't really find anything. All the hoses and vacuum lines seem fine.
Does anyone here know how to use the Diagnostic LED and pushbutton under the hood to read codes?
Any other ideas? (<--- read HELP PLEASE!!)

rev9k

An update:
I removed the Cold Start Valve and attempted to start the car while it was in view. The Cold Start Valve is spraying gas very well.

I removed each fuel line checking that fuel is pumping. All good.
The main line from the tank pumps plenty of fuel as soon as you turn the key on.

QUESTION: Should the pump continue to pump with Key On, Engine not running?
I ask because I was turning the key to on and the gas would pump out about 1/4 cup of fuel and then stop. Im assuming its because of pressure and if it was all hooked up right it would pump again when needed as the engine is running??

With everything connected normally, I disconnected one of the injector lines to the #1 injector right at the top of the Fuel Distributor. I attempted to start the engine and did not see any fuel squirt out of the Fuel Distributor. I then disconnected all the injector lines at the fuel distributor and attamepd to start the car and no fuel came out of any of the four holes in the top of the Fuel Distributor. I have now removed the Fuel Distributor and I am hoping it may be the "Electromagnetic pressure actuator" *(that part description is from the Haynes manual).

I welcome any ideas on this. Thanks in advance.

rev9k

I have determined, that for whatever reason, the Fuel Distributor is not pushing any fuel at all to the injectors.

The car runs just long enough to deplete the fuel being supplied from the Cold Start Valve, which is working and then runs out of gas.

So why would the fuel distributor fail doing its job?
What can I do to fix it?

pctarimu

I did have this problem with my 190E 2.6 W201. It is a 20 yr old machine. I decided to swap engine with a Japanese 1G-FE 2 litre. How fine, & smooth. One thing of a fact is that these Star machines are truly durable..engine and body. But once the engine starts trouble, at 250k km on the odo, given tht parts are so expensive, in Africa, as Mercedes are not so common here -its high time u think of replacing the plant /engine, if u love yr Star. Toyota is very common in Africa. Parts are very cheap (compared to Mercedes) and very reliable too. A new fuel distributor costs like the whole engine of a used but reliable Japanes engine of this standard. If there is a possibility of getting the same power, (& there is alot) at a third the cost of the Star, why not change that plant? U still have the Merc body untouched, with its fine Merc handling. No mistake: Toyota is still number ONE on reliability - in the world. I tried it. And i am happy.

ichberliner

I am currently experiencing very similar problem of what you described in your posts. My question is, were you ever able to get the car running and if so, what was the culprit (or prevailing culprit in some cases) ultimately?

Hope to see your response.


Anthony
California

miaracing

How did the cold start valve look ? Did it spray for just a second or did it spray continuously while cranking ?

joelmullen

Change the fuel filter.