Starts, doesn't idle high enough, then cuts off 89 300sel..

[jay3000]

Seems to only happen when it's warm.. Engine will immediately start up, and cut right off, because it doesn't idle high enough.. It may do that a couple of times in a row, before it will start right up, and run beautifully..

Opening the throttle a little will overcome this problem, but I shouldn't have to do that..

Just an FYI.. The engine runs perfectly otherwise, but does seem to idle a little lower than I would like.. About 600 in park..

Any help would be appreciated..

Thanks,
Jay

This appears to be a common problem. I'm beginning to suspect the fuel I'm using.

Meanwhile, try starting the car with the A/C compressor off and then turn it on after it starts. This seems to take just enough load off the engine that it will keep running. It works on my 300E and keeps my wife from complaining.

[Duke2.6]

Common complaint and seems to be the nature of the 103 beast. Get in the habit of giving it a little throttle just as the engine fires on a hot start, and it should cease to be a problem.

We've come to expect no cold or hot start throttle inputs compared to the various throttle manipulations required for carbureted cars, but if the car misbehaves we're better off adapting to its idiosycracies than chasing ghosts trying to get the car to comform to our expectations.

Like people, older cars can get a little cranky and set in their ways as they age.

Duke

[Mike Richards]

The following URL may be of interest. According to the author, there are 3 kinds of pressure in the KE system: system, control; residual. He also indicates that fuel pressure or the lack of it, often times accounts for many KE problems.

Residual may be an issue in your case. It may be worth looking at:


http://www.isham-research.com/quattro/pressure.html

[jay3000]

With the exception of fuel pressure, does anyone else have anything else I could look at?? I don't believe it's a fuel pressure problem.. Even if you turn the key on, and let the pump run until it stops, the problem still occurs, with absolutely no change..

When its cold it starts right up, and runs perfectly.. When warm, or hot either one, you can just bump the starter, it starts right up runs smooth for a moment, and cuts right off.. It may take several tries to get it to run again, at which point it runs perfectly..

It turns out that opening the throttle does not overcome the problem according my lovely wife who is starting to think that her Park Ave Ultra was a better car, and might want it back..She doesn't know that I have MODIFIED for my driving enjoyment..

Thanks,
Jay

[jay3000]

Then, I guess I will be on my own...

[Mike Richards]

Vacuum perhaps.

[sbourg]

It could be lots of things, including worn feedback pot in the airflow meter (wears through at idle position), vacuum leaks (air intake that does NOT get metered), intermittant throttle position sensor (KE system does not sense throttle closed, and thus does not activate idle air valve), etc. Note that a 'warm start' condition usually involves combustion chambers that have cooled from running temps, and fuel ignition will require precise metering. A cold engine has help from the cold-start valve, and a running engine will be less picky.

Steve