warm starting issues
 

Love our first Mecedes....until we have to start it.
Our 86 300e starts fine cold with a little hesitation sometimes after intitial start.
Once warmed up she will start right away if within 5 minutes.
Longer periods it will take 10-12 seconds of turning over before she will run.
When first turning over the engine seems to fire and then die as if there was some fuel present.
Had tech advise leaking injectors flooding the motor but I don't sense or smell a flooding problem. Another suggested the pressure regulator. Replaced it with no change.
If the car idles for a few minutes it sometimes starts to miss until you get rolling and also the O2 sensor is intermitently coming on.
Another problem is I bought the car with a non functioning cruise control that I would like to fix. Suggestions for sequence of checks would be great.
Sure glad I found this site and look forward to learning from all of you.

What year, what model, what engine? My Amazing Carnac turban is at the cleaners.

Try warm starting with the gas pedal held open. If it's flooding due to leaky injectors, this should help it start easier. If it's no difference, or harder to start that way, then it's likely not flooded. The miss at idle could be gas fouling, which may account for the O2 light. Another common problem for a miss at idle is oil getting past the valve seals and guides. Mine does this a bit, and it's getting new seals as soon as the heat and work give me a break. Keep an eye on oil consumption. For this, and other issues, you'll find the Search function to be very useful.

warm starting issues
 

Thanks moneypit.
I have tried depressing the gas pedal before after and during the start and it doesn't really help.
Because we are in the middle of a move I am running out of time to personally try different options. I am going to get a tech to look at the car in the next couple of days for a possible diagnosis.
As far as oil consumption. I made a 4500 km trip recently and used 3 litres of oil. By the way there is 188,000 km on the car.
Appreciate your help.

When you figure it out please let us know. My 190E with the M102 starts great cold and great within a minute or so, but any longer than 5-10 amd I need to crank her for about 5-10 seconds!

The miss after a few minutes idle time sure sounds like a valve seal, but your oil consumption says that this is not a huge issue. Do the valve seals and check the guides when you get a chance.

If it's not flooded when it won't start, the next thing to check is if it's not getting fuel. The best way to check would be with a fuel pressure gauge hooked up to see where the pressure is while cranking but not starting.

An easy way to get an indication would be to spray something flammable (carb cleaner, WD-40, or similar) into the air intake while trying to start. Look for better, worse, or no change. If this improves the condition, or even starts and runs for a few seconds, it indicates a lack of fuel in warm starting conditions. I'm not sure of the specifications for residual fuel pressure (pressure that the fuel system is supposed to maintain after shut-down), but it sounds as if the engine won't start until pressure builds up in the fuel lines.

First off, if your car is using 3 liters of oil every 4500 kilometers (~3 US quarts ~2700 miles), there IS a problem. That is A LOT of oil!

Definitely sounds like it's time for some valve work. However, I'm not so sure that's going to solve your hard warm-start issue. It might be that the plunger seal is worn out in your fuel distributer and allowing some fuel to drip out while sitting. It could also be a leaky fuel accumulator.

I think Steve was the one who posted info on this a while back. When pressure is relieved in the fuel system (due to a leak) it will boil at a lower temperature and cause a "vapor lock" situation, until more fuel is pumped through, which is what is causing your longer warm starts.

warm starting issues
 

Hey I found the problem with our 86 300e warm start problem.
After trying a fuel pressure regulator that didn't siolve the problem we put in a new fuel pump check valve and problem solved.
Irieite defined a sysmptom that got me thinking. Thanks.
Since I couldn't detect any sign of leakage to the outside of the fuel system or into combustion chambers I figured it must be seeping back to the tank.
$28.00 and change and my wife is happy. Happy wife, happy life.
Thanks again.
Next is cruise control and climate control vacuum leaks.

cool
 

my 84 500sec does the same thing. i have been living with it for three years and 50,000 miles because my indy couldnt figure it out. i bet it is the same thing. it acts exactly as described.

tom w