After a good cold start my 190e 2.3 takes 5 or 6 tries to start after it gets hot but sometimes can take up to 3 hours before it will start. Problem worse in summer. Runs good when it does start. I was thinking it might be an elec problem but something I did last time makes me wonder if it is fuel. When I took the fuel line off of the injector module there was no pressure, i.e. no fuel squirted out until I keyed on, then a stream a couple of feet. So, vapor lock seems possible but for 3 hours? Any help?

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85 300 SD ~ 115K
82 500 SEC Euro ??K
78 450SL 164K

try to start it when it won't and see what's missing. no spark or no fuel. could be a number of things-fuel pump relay, crank sensor, ezl unit, low rest pressure(unlikely). vapor lock is not an option if the fuel pump runs when it's supposed to and the accumulator and/or fuel pump check valve is/are doing the job. no 1 item sticks out. you need to test. good luck, chuck.

From threads I have seen posted on here it points to the way a CPS does when bad. It would be a definite one to test.

Will do some tests soon. Now I have wiring diagrams and a meter in the car.

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85 300 SD ~ 115K
82 500 SEC Euro ??K
78 450SL 164K

I think rebe has nailed it. My 300E had the exact same symptoms. A used sensor out of a 180 fixed it. Any sensor from a 4 or 6 cyl model Mercedes of the period should fit and might be a cheap fix for you.

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1990 300TE

"24 hours in the day. 24 beers in a case. Coincidence? I don't think so."

You can check for a HOT spark output at any of the wires OR the coil wire.
Just open the gap on a regular plug OR cut the ground electrode off & see if the spark can jump to the case of the plug.

CAN also be the fuel accumulator!

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

Just now able to get back to the car. I have spark when it won't start hot. Also checked ohms of temp sensors and all are in range. Must be some kind of fuel problem. How do I tell if the injectors are leaking or if it's the pressure reg not holding?

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85 300 SD ~ 115K
82 500 SEC Euro ??K
78 450SL 164K

To really know if the fuel pressure is being retained, you need a fuel pressure gauge.

However you can test the fuel accumulator w/o special tools.
There are several good write ups on that test.

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

The problem was getting worse - missing for 3 or 4 seconds when it finally started hot. I thought that might mean flooded so I bought new Bosch injectors but still same problem. I have found that it seems to start faster if I hold throtle to the floor while cranking. So, it has fire and new injectors, the sensors are within range but still seems to be flooded. What else could it be?

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85 300 SD ~ 115K
82 500 SEC Euro ??K
78 450SL 164K

I would test the accumulator as others have suggested. No special tools needed.

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http://i193.photobucket.com/albums/z...-RESIZED-1.jpg
1991 300E - 212K and rising fast...