hard to start when warm

[bcjm]

I have had this problem for a while. I like to find out what exactly is not function properly.  The car always starts fine instantly, cold or hot. It only happens when I let it sits for about an hour or two after driving.  It will start after 2-3 tries and I need to crank the engine for more than 10-15 revolutions.

I think it is due to leaky injectors.  Is there a good way to tell?  What do you think?

Bob

[Cees Klumper]

Try these two things:
- start it with full throttle (this is what the owner's manual suggests) - obviously let go of the pedal when the car starts
- turn the ignition on, then wait maybe 8-10 seconds while the fuel pump is humming before you actually attempt to start the car - while also applying some throttle. This works for me.
The hard warm start is a notorious issue with our cars. There are probably all kinds of other things you can try / check out, you can check the technical articles and the posts on this site through the 'search' function for more tips.

[Bearcat]

I have the exact same probs....I'll try the next time with full throttle.

280SL 1970
SL320 1998

[Richard Madison]

Don't mean to be a precision nut (which I am most of the time) but the English version of the 280 SL Owners Manual does not say "full throttle". It says (Page 17, exact quote):

"With lukewarm or warm engine accelerate simultaneously with starting operation."

"With a cold engine, don't operate the accelerator pedal right away; when engine begins to fire, accelerate slowly, but release ignition key only when engine fires regularly"  

My comment: the Owners Manual was not written (or translated) by a native English speaker. "Accelerate" commonly means "make the car go faster". In the Manual, "accelerate" seems to mean "move the gas pedal".
 
So "accelerate" in the Manual might mean press the pedal all the way down and hold it (full throttle); or pump the pedal while cranking; or press the pedal part way while cranking.

This is just to clarify that the words "full throttle" are not in the Manual; the instructions are not precise. But the Manual is clear: when starting a warm car, some pedal action is needed.
Richard M

[Albert-230SL]

In the Workshop Manual appears a new word: "rightaway", in the operation of starting a hot engine (together with other causes of the problem):


 
What's the meaning of this word?

Regards,

Albert de la Torre Chavalera
Barcelona (Catalunya/Spain)
Feb.'64 230 SL Euro 113042-10-002432

[rwmastel]

Albert,

They simply left a space out.  It should be "right away", as in "right now" or "right at that moment".

Rodd
1966 230SL Euro
1994 E420

[hands_aus]

Hey Bob

What model W113 do you have?

On the 280sl a 2 second relay was introduced to the cold start relay circuit. This fires your cold start solenoid on the inlet manifold. This happens with either a HOT or COLD engine.

This additional relay was available as an option for the earlier models and came with a small additional wiring harness.

If your car has this relay and it is not working properly then you will have starting problems.

I press the pedal half way after letting the pump run for about 10 seconds as Cees suggested.

Albert-230sl,

rightaway means immediately

Bob(Brisbane,Australia)

[bcjm]

My w113 is a 1971 280SL.

The car starts fine with no throttle either HOT or COLD.  It only happens when let it sit for an hour or two after driving.  I will try throttle half way the next time.

Bob

[Ben]

My '64 will start instantly hot or cold or semi cold ONLY if I follow the instruction book to the letter. If I stop to refuel and dont apply the throttle whilst starting I would be there all day, it will never run. If I twist the key AND press the pedal at the same time slowly it will fire straight away !

When cold it will start instantly but immediately stall. Then second try it will idle no problem, if a little low. I reckon I need to adjust the washers under the thermostat housing to get it to idle higher when cold.

Regards,
Ben in Ireland.
'64 230SL 4sp.

[Shvegel]

Bob,
 My car started hard when it was warm. I found that if it sputters and runs rough immediatly after a warm start it is generally an issue with the injectors leaking or the ball check valves leaking on the injector pump. What happens is the fuel in the hot fuel lines(between the injectors and the fuel injection pump) boils in the lines and forces the fuel out on one end or the other leaving the lines at least partially full of fuel vapor. When you try to start the car it takes a while to refill the lines with fuel hence the hard start.
  As a rough diagnosis see if there is black smoke coming out the exaust when you start the car warm. If so you probably have a leaky injector problem. Other than that pulling the injectors and having them tested will give you a definitive answer. As for the outlet check valves you will need to follow the test in the BBB to find the offending valves.

[Albert-230SL]

quote:Originally posted by Ben

...
When cold it will start instantly but immediately stall. Then second try it will idle no problem, if a little low...
Regards,
Ben in Ireland.
'64 230SL 4sp.

Hi Ben,

After some days of not starting the car, I had identical problem. Now, I leave the ignition on during 8-10 seconds before to crank, and it starts perfectly and doesn't stall. During these 8-10 seconds, the electric fuel pump provides the required fuel pressure to the whole fuel system. Maybe it could work for you.

Regards,

Albert de la Torre Chavalera
Barcelona (Catalunya/Spain)
Feb.'64 230 SL Euro 113042-10-002432

[mulrik]

I had similar problem and changed the (worn) ignition distributor, that cured it!

'67 250 SL Papyrus White 113043-10-000023

[Cees Klumper]

Mulrik, that's good news. I recently rebuilt a distributor and will install it with my overhauled engine (see topic http://sl113.org/forums/index.php?topic=389), that will be delivered to my garage next week (BTW: total shipping cost for two engines was only $500, from Joe Alexander in Columbus, Ohio to my door in Amsterdam    !).

Cees Klumper in Amsterdam
'69 white 280 SL automatic