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Hard cold start

2K views 6 replies 4 participants last post by  macabethiel 
#1 ·
I have a 1991 300TE 4MATIC, when the temperature is under 20 degrees F the car continually cranks and will not start. I know one of the fuel injectors have a leaky seal, because I tested it with a can of starter fluid, by spraying around the seal while the car was running, and the RPMs increased. Later in the day, when it is warmer the car will start right up, and performs flawlessly. I have replaced the cold start valve, checked the OVP relay, and replaced the fuel accumulator. Please don't tell me this is going to be a warm weather car, I enjoy driving it all year round. Please help. :confused:
 
#4 ·
cold start issues

I had a similar problem on my 300 TE 4-matic. It was the fuel relay. I took the top off the relay and found a dry joint that I repaired and it was cured. As I go to France several times a year from the UK on the booze run I decided to buy a new relay to be safe. No problems since then. You often find that giving the relay a tap with a spanner or wiggling the big connectot makes the car start as though it is hot. I found the remedy on an American website. You can get cheaper relays from Eurocar parts but I went for the gunuine MB part. Mine started playing up at 105K. I now have 115 k on the clock problem free. The relay is behind the battery.
 
#5 ·
anyone,

89 300e. scenario- accumulator is good. cold start valve/function is questionable. should not the engine at least try to start in the morning? hot start problems resolved with accumulator. i hope. my cold starts are 10+ seconds minimum. BTW, even at 10+ seconds my foot must be off the pedal or cycle will last longer. once running all is well. i thought cold start valve was just a second or 2 of fuel. just enough to help the engine get going. mine acts like an old chevy that has had the fuel pump replaced and having to suck fuel all the way from the tank. any help??
 
#7 ·
Yes its to the left of the OVP relay its quite a substantial relay the part number should be vissible on the top its now MA 003 545 24 05 it was something like 003 545 03 ? last numbers have worn away ON MY OLD UNIT . It has 9 contacts, numbered 31,15,87 then 50,TD,30,87k,87v tf. and it looks like sealed in plastic but you can easily cut round the base and break the seal without damaging the casing or internals. You can then lever it open. Its usually contacts 30 & 31 that cause most problems. My car was fine in the summer but in the winter it got to the point where it was almost impossible to start.
 
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