Starting 190E 2.3-16

I have a temperature specific starting problem with this car which is getting worse. Last winter it started fine. When the weather got warmer (warm enough for the cold start injector to be out of the loop) it took
several seconds of cranking to get going. Now that winter is back I expected it to start okay again, but now it starts on the fuel from the cold start injector and will starve right away and die - running for only 1 second or so. If I keep cranking even after it seems to start, it will start, die, crank for a few seconds just like in the warmer months, then eventually catch and run fine. So it seems that the problem is definitely fuel related, as if the pressure is not being maintained while the car sits and the fuel in the system isn't catching up to the fuel from the cold start injector. I'm curious though - if system pressure was down, would the cold start injector still have fuel to shoot?
There is no gas smell under-hood or anywhere else. Two years ago I replaced virtually the entire fuel system - fuel pump (this is an early 16V with only one pump), accumulator, filter, injectors, EHA. My first guess is the accumulator, even though it was replaced previously, but before I go replacing parts based on guesses, I though I'd tap the vast knowledge base here.
Any other likely culprits?
TIA,
Bill Balmer 1986 190E 2.3-16 first 16V in the US featured in Car & Driver March, 1986
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sparkplugs?
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Bill, the fuel pressure can be checked through a "leak down test" but, IMHO, that's not the car's problem.
The cold start system operates only very briefly - just seconds.
I suggest that a sensor is not functioning correctly and its value is out of the computer's range or its value is false. For instance, an incorrect temperature input for the computer's control of the engine's idle subsequent to cold start could starve the still cold engine of fuel. And that's apparently what's happening.
There may be several temperature sensors to be checked, including one in the MAS. I don't know the details of this model so this is speculative in my part but said to widen the possibilities beyond the obvious.
Hope this helps you get it going, even on the coldest day of the year.
Tom
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Thanks for the reply. I'm not sure I understand how this could be a sensor though. I HOPE you're right and that's all it is!

Yes, this is consistent with the symptoms. It acts like the burst from the cold start is enough to make it start, but there's no other fuel following that so it won't keep running if I disengage the starter at first catch.
Maybe my description wasn't clear - the whole process takes less than 5 seconds, warm or cold. When the weather is warm, it cranks for 3-5 seconds then starts; when the weather is cold (45F or less - the engage point for the cold start valve based on the air temp sensor) it starts immediately upon turning the key, but will only run for a second if the key is released. If I hold the key in the start position, it will do the same, but if I continue to hold the key in start, it will keep cranking and start for good after another 3 seconds or so - just like in warm weather. Either way, it always starts eventually, and once it has started, it idles and runs perfectly. Also, if the engine is warm, it starts right up.
So the problem is present in both warm and cold weather, but the shot of fuel from the cold start valve just makes it seem a little more eager when it's cold out.

Wouldn't this cause poor idle performance even after the engine starts? Idle is good, mileage is good, performance is good, just passed state emissions test, plugs are good.
I don't mean to ask for your advice and then shoot you down. Like I said, I probably didn't describe the problem well the first time around. Thanks for the help, and if this post has confirmed or changed your theory, I'd like to hear it.
Bill Balmer 1986 190E 2.3-16
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I would change the temperature sensor that the fuel injection system uses... engine will run regardless of that it reads... just crappy. Warm or hot engine has nearly no effect on the temperature sensor.
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"once it has started, it idles and runs perfectly"
Ok, then let's go back to the cold start system which has a thermo-time relay (colder = longer [cold start valve] ON). Your enhanced description suggests that the cold start system's ON duration is too short. That means the thermo-time relay is the suspect.
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An easy test is to check the resistance of the cold start injector. If it's about 9 ohms or so, you're OK. If it's zero or infinity, you have probably found the problem. Once you know it's not shorted (0 ohms), you can do the following.... Wire up a fresh 9V battery to your cold start injector (get the polarity right!) with a normally open pushbutton. A battery, a few feet of two conductor wire (like speaker wire), and pushbutton will set you back about $6 at Radio Shack. When you push the button, you should hear the injector click open, and click closed again when you release the switch. If not, your cold start injector may be clogged or otherwise dead. Start the car, while tapping the button. If it starts easily, it's the injector control circuit. If not, it might be the injector itself. The wife's 190E has a problem where the computer is not sending any voltage to the cold start injector, regardless of what the input temps are. So, I've got it wired with a permanent setup as above. When it's cold, she pushes the button and starts her car. I changed the 9V batteries out twice a year. Yes, it's a total kludge, I know, but it works, and a USED computer is about $800... Dan

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It cranks for several seconds before starting when the weather is warm and the cold start valve should not be activating at all. I don't believe it's the cold start valve.
Bill Balmer
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