Start Car Procedures

[n/a]

I would like to know what the proper procedures are in starting our car in cold and warm engine conditions. I heard various recommedations: cold engine - pump gas once (twice if necessary) and let car warm up a few minutes before driving; warm engine - gas pedal half way (or is it all the way?) and release gas pedal when engine start. I also heard that we should not pump gas pedal at all when starting these car. Also, are there difference between auto and manual? Like to hear what others do.

Louis 70 280sl red auto

[Douglas]

I don't touch the pedal at all when I start my automatic. On my stickshift SL, I would also stick the clutch pedal in when starting.

I'd like to add to this thread with a related question -- when it doesn't turn over immediately, do you favor cranking it for a few seconds or do you prefer shorter bursts?

Douglas Kim
New York, NY
280 SL #016220

[Raymond]

Short answer? There isn't a short answer.

With cars that average 38 years old, the starting ritual is going to become pretty individual.  If everything is perfect, the car starts with a twist of the key and nothing else.  The Cold Start Valve does the "pumping" for you.  Now with variations of compression, ignition, fuel mixture, phase of the moon, wife's attitude, whether or not the dog is in the back, etc., each car is going to be a bit idiosyncratic.  Cold, (a relative term in North Florida ) my car was firing off after about three revolutions, and that was before I tore it down to rebuild it.

For warm up, the owner's manual suggests that you drive off slowly and at moderate speed, rather than allowing the car to idle to warm up.  Again, that is going to be a little individual depending on the condition of the engine and transmission.

For Doug's question, I hate to grind a starter.  If the car isn't starting in just a few revolutions, something is out of adjustment.  However, it doesn't snow here.  In the extreme heat, I guess there could be some issues of fuel evaporation that require you pump some air for a bit before it caught.  But the fuel injection pump should have the pressure to overcome that.

Ray
'68 280SL 4-spd Coupe

[jeffc280sl]

I would say that if everything is tuned and set properly just turn the key.  You have a fuel injection system versus a carb.  It has devices to tell its cold and the mixture needs to be richer.  There are many variables in the tuned and set properly caveat.  What does your car do or sound like when you just turn the key?

Jeff C.
1970 280SL 4-speed

[JimVillers]

Like Raymond says, much depends ..... Fuel injection means that pumping does nothing.  Short cranks should trip the a second shot from the cold start valve for each crank which would richen it to start or flood it so it won't start.  

Mine has a tendancy to flood when it is hot and needs a wide open throttle if it doesn't catch.  When cold, it starts instantly but wants some throttle to burn off excess fuel.  I guess that I should take a quarter turn on my two second relay ..... but it isn't broken so don't fix it is my normal aproach.

Like Raymond says, they all have a personality.

Jim Villers
190SL, 230SL 5-Speed, 190E 2.3-16 Kompressor

[A Dalton]

All have their little trick, but a good practice is to leave key in run position for a few secs before cranking. This assure a good flow from the electric pump.. and if real hot, it helps any vapor problems from occuring..specially near the front filter mounted to the motor mount.
 Fot rapid starts , the later starter and 12v direct for ignition during crank [ Resistor by-pass] help and work well.[ same can be done with ice cube relay on older units w/o third wire on sol.]
Lastly, I like cabin sw. CSV control too..does not mean you scrap the TTS or Time relay circuit , you just have it in tandem [ parallel circuit ]for operator over-ride of the system.

[n/a]

I have been able to start a cold engine just by turning the key. I had received some advice about pumping the gas pedal and let the car idle for a few minutes before driving. I did none of that since the car starts ok. On a warm engine, I have to depress the gas pedal all the way, turn the key, and release the pedal after the engine starts. Since these are all 35-40 years old cars, they are all going to have their own characters on how they want to behave. I am curious on what a cabin sw is going to do and why you need to over-ride the system? Is this for extreme weather conditions?

Louis 70 280sl red auto

[Ben]

Since finally tuning my car correctly and getting all the little systems working properly my car starts by the owners book, basically do nothing when cold except turn the key, its starts after about 2 seconds and idles about 1100RPM.

When hot I give it half throttle and release once it starts. This can take longer, maybe 5 seconds and if I have just driven for a while and stopped to get gas I give it 3 short bursts of the starter and it will ALWAYS start. If I sit there cranking it will flatten the battery before starting !

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

[J. Huber]

Darn. Can't remember...Guess I'll have to go check  

Mine starts similar to Ben's. Cold, I turn the key and its starts. I have a habit of nursing the throttle just after it it engages.

Warm, I sometimes give it a smidge to catch it. In both cases, it starts very quickly. This was not always the case -- I think my TTS was faulty for years -- and cold starting was at times a major adventure.

James
63 230SL

[glcg123]

Now that I have had my CSV valve serviced it is a great starter, cold or warm. For cold I turn the key and wait about 5 to 10 seconds to ensure there is fuel at the injection pump befor engaging the starter. It fires right away and idles perfectly.

When hot I turn the key and wait only 2 to 3 seconds before engaging the stater. It starts right away again.

George

[A Dalton]

<<I am curious on what a cabin sw is going to do and why you need to over-ride the system? Is this for extreme weather conditions?
>

 Yes , it is for different conditions. The main one is when trying to start after a short term stop in hot weather. A quick squirt solves the problem.
 Mercedes came out with an additional 1 sec relay Kit to solve this problem , but if you have the cabin sw. and know how to use it, you don't need the 1 sec relay modification kit.
 I find that the owners who like the cabin sw are the tech guys , as they know what the engine is looking for.
 ..but the CSV,TTS and circuitry work fairly well if they are all up to par..and if one is having the above problem, it can be corrected with the 1 sec relay and harness 108 540 10 09  modification kit. It is a plug in kit.
 The 1 sec relay was actually used on the early versions [ .042] systems ,  but they did away with it as the CSV circuits went through 4 changes . And even after the 4th version, they found that some needed the addition of this kit , so the system was never really perfect..but it's flaws are easily remedied if you have an over-ride sw. at your calling...[ my opinion]
 

[J. Huber]

A divergence slightly but -- I just started the car up cold -- true to my earlier testimony, it started right up. However, without engaging the throttle it seems to fluctuate RPMs for a several seconds... Any idea what this would be? On a warm engine, it locks right into a steady RPM.

James
63 230SL

[A Dalton]

quote:Originally posted by J. Huber

A divergence slightly but -- I just started the car up cold -- true to my earlier testimony, it started right up. However, without engaging the throttle it seems to fluctuate RPMs for a several seconds... Any idea what this would be? On a warm engine, it locks right into a steady RPM.

James
63 230SL

 A possible injector line check valve problem, specially as you have an R-11 pump.
 These originally had cone check valves and were prone to leaking back after a long sit. [ overnight],  So , you get the car started with fuel from the CSV OK, but then it stumbles around a bit til the lines from the pump replenish.  This was Factory rectified on the later pumps [after R-18Y, R-18Z and on.. to be specific] with a swap to Ball Type valves .This would be the late .043 chassis and the last series of dip stick pumps.
 Your pump can be modified to the newer type valves without much work, but most just put up with it...
 Benz part  M-B 000 074 17 15 . [ 6 required ]

[graphic66]

I have learned to succesfully start my car as outlined in the owners manual on page 34 (230SL).Set the ignition key to position 2 then turn to starting position after only a few seconds. At first do not operate the accelerator pedal while the engine is cold' as soon as the engine starts firing, step slowly on the gas pedal, but only release the ignition key when the engine fires regularly. With a warm engine accelerate already  when starting the engine. I follow this and have great starting. I find it very important to let the starter get the engine firing good before releasing it as this activates the CSV. I just give about half throttle when the engine is at all warm. After firing of the engine, rev up for a short while to incresed speed, then release the accelerator pedal so that the engine is not accelerated to much. With the vehicle stopped don't accelerate higher than 4000RPM and don't load until oil pressure indicates.  I have found that letting the fuel pump run for more than a few seconds before starting has no effect whatsoever. If the car has sat for a few weeks I will use my remote CSV switch I installed in the cabin to make it easier on the starter. All of this worked only after setting all of the injection levers and controls to factory specs. Now it starts perfectly every time just following the instructions in the owners manual.