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Discussion Starter #1
I inherited a 1991 W201 that had/has many issues however I am just not able to let go. I continue to chase the issues because I love driving the car. My 190 has over 200,000 miles on it and I have already put a good deal of work into it. I have replaced the fan clutch, cap, rotor, plug wires, O2 sensor, injector seals, belt tensioner, A/C compressor, and exhaust. The car still needs more TLC. Currently my issue is that when the car sits for more than 24 hours or so it is hard starting and seems to starve for fuel. At idle it seems to stumble and quit. If I am able to keep it at idle when given a full pedal it will again seem starved for fuel and quit. After fighting with it for about 4 or 5 miles it will start and run fine. I have no problem with warm or hot starts after that and even when I drive the car daily only after a day or 2 of inactivity will it act up.

Any thoughts?
 

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1991 190e 2.6 automatic
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or you might have a vacuum leak

take a flammable liquid such as starter fluid or brake cleaner and spray it around the IDLE control valve and all over the hoses while the car is running rough... if it smoothens out or the rpm goes higher while you spray it, you found a leak there. Spray some around the throttle body also ( not into the throttlebody but around the rubber boot and housing )

spray it on any vacuum lines you see

but dont spray the ignition wires or else you might cause a fire if they are leaking


if that doesnt work, spray the ignijtion wires with water in a dark garage and watch for escpaing electricity in the wires.
 

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'87 190E 2.3 Manual, '81 500SEL 4whl SLS, '91 300SEL
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It sounds like cold start enrichment is not happening. Check your cold-start valve for function by jumping it off the battery. It should click when you touch negative and positive to it.

If it clicks when you jump it, then it is likely still working, you could remove the part and jump it while spraying it into a container to see if fuel comes through. "Priming" the fuel pump by turning the key to on should build enough pressure that the cold start valve will dispense fuel.

If all that checks out, your problem probably lies somewhere else. You could have a bad coolant temperature sensor, making your computer think the car is "warmed up" even when it's not. The sender for the dash temperature is a totally different sensor, so you cannot tell if the computer coolant temp sensor is bad by this.

My car has a similar issue because the computer is not functioning at all due to PO's negligence, does your Check Engine Light stay on, or not come on at all (even during pre-start when all lights are supposed to)?
 

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98 SLK230K AMG, 98 E55T, 89 2.5-16
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....I have no problem with warm or hot starts after that and even when I drive the car daily only after a day or 2 of inactivity will it act up.
it sounds like you are losing fuel pressure slowly. it's not the classic symptom of a weak accumulator though so i would hazard a guess of leaking FPR or fuel pump check valve.

hope you get it sorted soon.

regards,
 

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201 Gremlin...hard start

i guess we are on the same boat.. had my 90 ' 190e 2.6 tested before,shop could not find anything wrong aside from replacing my 2 fuel pumps.
nfsjunkie91's observation, make a lot of sense too (worth trying out) checked out my O.V.P. and seems fine..
is the cold start valve and cold start injector the same? .. vacuum leaks may also be good cause for hard start...
will check out my cold start valve as soon as i have the chance...
thanks so much for all the suggestions.... t2
 

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Discussion Starter #10
I have removed and cleaned my idle control valve and the ovp has been replaced. Since cleaning the Icv I have been driving it everyday with no problem as evpected when running every day. This past w/e it was not driven and the problem is still there. I would think that if it is a vacuum leak or a cold temp sensor it would occur all the time or even after the car has cooled down over night.

Guess I will continue hunting.

Baffled!
 
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