Cold start

[n/a]

I have seen other discussions on cold start problems, but none of them seemed to be the same as my problem.

I have had this nagging problem with my car when trying to start it when it is cold outside (less than 60 Deg. – it generally does not get very cold in San Diego).  When I go to start the car in the morning it will start up just fine.  It will run for about 3 to 5 seconds, and then it dies like it ran out of gas. I restart it and it continues to work fine for the rest of the day.  

1966 230 SL


R Rose

[graphic66]

Try holding the key in the start position just a little longer after the car begins to fire.

[Cees Klumper]

Doesn't that mean the starter will continue to spin?

Cees Klumper in Amsterdam
'69 white 280 SL automatic

[Benz Dr.]

Leaking check valves in the injection pump or at the fuel pump.

Daniel G Caron

[A Dalton]

Originally posted by Benz Dr.

Leaking check valves in the injection pump or at the fuel pump.

Daniel G Caron

 I agree w/Dan..
 The pre R20 injection pumps had cone check valves that are famous for leak back ... they can be changed to a newer ball valve to solve the problem...
 A tip to checking if the problem is at fuel supply from the tank pump is to turn the key on for 10/15 secs before attempting to start.
 This pressurizes the feed line . If that eliminates the problem, then look at the check valve at the electric pump.
 I have the part #s of the cone valve injection pump mod, if needed.
 Check your Injection pump oil level too....

[Mike Hughes]

You might also check the cold start valve to see if it is a little grungy.  Mine had been leaking some and ultimately was so grungy that, even though it was working just fine electrically, it couldn't produce much of a spray at all. A proper cleaning made all the difference in the world.

- Mike Hughes  -ô¿ô-
  1966 230SL Auto P/S
  Havanna Brown (408)
  Light Beige (181)
  Cream M-B Tex (121)

[A Dalton]

Mike also has a point..
 But in this case , it would be a leaking CSV that actually floods the engine by leaking by after key is moved to Run position.
 That can be diagnosed by taking the hex test plug off the CSV and looking for fuel with key on... there should be none.
 What would lead me to doubt this is that it is pretty hard to stall a cold engine by running it rich...

[Mike Hughes]

In my case what happened isthat the leaky cold start valve got so grungy that it eventually almost completely stopped itself up.  So it wasn't able to richen the mixture accidentally or on purpose.  Cleaning it and correcting the leaking problem solved my cold start issues, including similar symptoms to what R Rose is describing.

- Mike Hughes  -ô¿ô-
  1966 230SL Auto P/S
  Havanna Brown (408)
  Light Beige (181)
  Cream M-B Tex (121)

[A Dalton]

I know what you mean..
 Usually , if the car stalls after the key is no longer in the start position, it is not getting the required fuel from the IP.. That is b/c the lines have bled back when the car sat. [ IP check valves]
 The only time the CSV is in operation is when the key is in the Start position. [ and below 65C]
 The other possible is the early pumps had a start assist solinoid that moved the rack foward to get more gas to the injectors , but again, only in the Start position. [ regardless of engine coolant temps]

[n/a]

Thanks for all the input.  I have not been available to check this site.

I doubt that the problem is the Fuel pump - as I have done several of the sugested test already.  I do plan on checking the cold start valve - as this is good preventive maintance item.  But I doubt that it is the problem.  So that leaves the Injection pump.

Dan, how much problem is it to correct the check valve in the injection pump. This is an item I have not ever worked on.

R Rose

[andy]

dont know if 230 is same as 280,i had this problem with my 280,started first time ,but would not tick over.type in WRD in the search section and follow the ways to check if your thermo and slide valve are doing there job. i am no expert just things i learned from reading the site.
andy
spain.