Coldstart problems 190E, 1989 (W201)

[austria40]

I have a problem that when the engine is cold it will start, but as soon i push on the accelerator the engine dies. Typicly i have to let it idle for a minute and then everything seems to be ok.
Today i tried to start it after the car was standing for a wekk and it took some time to get the engine running.

Felix

 

[joe bloggs]

First port of call the overvoltage protection relay fuse, bit fiddly to get to, behind the battery, next to the injection ecu nearest the heater, clear plastic top, with a red 10a fuse stuffed in. If this is ok the relay itself could be u/s, Easiest place to check it is working is at the idle control valve, this is fed via the relay (ignition on) red/yellow wire, red/white is control voltage from injection ecu.

 

[stwat]

It could be the cold start fith injector not working. There has been a number of threads on this same subject recently so i advise you do a search.

Stu

 

[joe bloggs]

Interesting reading, this is a bit of a surprise, as during my many years in the workshop I cant honestly remember ever having to change one of these injectors. Not to say yours is not at fault you understand, just personally unusual.

The Fuel pump relay which controls this cold start injector (on later models) has been a source of trouble in the past, but normally only affected the fuel pump side.

As your car seems flat even when (in normal use) the cold start injector would have stopped anyway I still suspect the electrical side of your injection system could be down, and the favorite trouble point is the over volt relay/fuse

 

[austria40]

Overvoltage protector was blown

First of all i would like to thank you all for your help. I checked the fuse and found that thie fuse was blown. So I replaced it yesterday and lets see how things going on. First impressions are good, the car starts now from cold without any sputtering.
Was a bit tricky to get to, but i found it

Felix

 

[stwat]

Thanks for the update Felix 8) I think Mr Blogs deserves all the credit as he was spot on with his diagnosis

Stu

 

[kezza039]

I have a problem that when the engine is cold it will start, but as soon i push on the accelerator the engine dies. Typicly i have to let it idle for a minute and then everything seems to be ok.
Today i tried to start it after the car was standing for a wekk and it took some time to get the engine running.

Felix

my hubby had the same prob told him to look at the ecu box by the battery ther is a 10 amp fuse take it out have a look he did and change it now his car works ok

 

[christiankay]

Does my 190E 1.8 Automatic have this overvoltage protection fuse? My car is having trouble starting. She fires after about 4 attempts, idles on 2-cylinders (if i push the accellerator it dies) if I leave it warm up shaking like hell barely alive the rest of the engine joins in and she will eventually idle normally and I can drive off? All very strange and annoying first thing in the morning.

 

[Alex Crow]

Does my 190E 1.8 Automatic have this overvoltage protection fuse? My car is having trouble starting. She fires after about 4 attempts, idles on 2-cylinders (if i push the accellerator it dies) if I leave it warm up shaking like hell barely alive the rest of the engine joins in and she will eventually idle normally and I can drive off? All very strange and annoying first thing in the morning.

yes, sounds like a possible OVP fault.
the unit is a silver relay with red top on that should be under a cover near the battery.

 

[christiankay]

New OVP from Mercedes dealer

Yes it was the OVP, bought and fitted a new one and all ok now.

£75 from Merc dealer

Was going to buy from ebay but was warned about dodgy electrics online.

Car works nice now.