Will not hot start

[dwilli3038]

With my car now running the grandkids came over Sunday for a ride. I drove them around the neighborhood then parked it and shut it off. My Daughter asked when would she get to ride, so I tried to restart it but it would not start. At this point grandaughter said she wanted ice cream. After a trip to the Marble Slab creamery, I tired to start the SL again and it started quickly. I gave daughter her ride and put it in the garage. I tried to re start it, no luck. later that evening once again it started easily.

So on Saturday when I start woking on it again where do I start?

Daryl
'64 230 SL
Serial # 508

[Naj ✝︎]

Hi, Daryl,

I had this problem with my 230 SL.

One short term answer (if you get stranded) is to carry a small jump lead and bypass the ballast resistor by using the jump lead from the battery +ve to coil side of ballast. Remove jumper after engine starts.

The problem was solved after checking the battery charging voltage. It was 13 volts instead of 14. Changing the regulator cured that...

naj

68 280SL

[Ben]

I had the same problem, and the same result !

After going through all the usual suspects my hot starting was perfect for years until one night parked nose in on an incline in a multi storey with my 5 year old daughter it refused to start !

Having tried a few things, removing the fuel pump and CSV fuses in case it was flooded and spinning the engine over wide open.I jumpered the Ballast and off it went. Turned out my alternator wasn't chargeing enough !

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

[ja17]

Hello Daryl,

Congratulations on getting the car on the road, it must be a thrill after after years of waiting. Sounds like you have a few more challenges. I presume the injection pump work did the trick?

By "hard starting" do you mean that the engine does not rotate quickly or it rotates and does not fire?

Joe Alexander
Blacklick, Ohio

[graphic66]

Are you holding the gas pedal halfway down when hot as per the owners manual intructions. I had some starting difficulties until I followed the instructions.

[JPMOSE]

Make sure your "Starting Solenoid" on the back of the injector pump is working. It engages every time the key is in the "Start" position and moves the rack within the injector pump to create a rich condition.  This particularly helps when the car is hot.

Best Regards,

J. P. Mose
1968 250SL
1987 560SL

[enochbell]

Daryl,

Improvements over the model years reduced and then eliminated the "hot start" problem but, in my experience, the very early configuration can be fussy even when it is working "properly".  They just don't want to start when hot.  If you want to eliminate the problem once and for all, and you don't mind a bit of Rube Goldberg under the hood, then here is my suggestion (and one that I got from this board by the many who have done the same, although I believe the number of these reported "fixes" is understimated to protect the purist...":  Install a momentary switch (a miniature Radio Shack push-button mounted invisible under the dash will work) and wire it to the start valve (I believe it is called the CSV: cold start valve) on the intake manifold, it's the aluminum cylinder attached just before the plenum (there are just two wires/two contacts, so not even an electronics moron like myself can screw it up) that allows you to manually operate the valve.  Operate the switch while you are cranking your hot engine: voila, no more hard starting.  You will get the feel for how much you need to juice the mixture, but this will solve your problem.

Best,

g

'64 230sl, fully sorted out...ooops, spoke too soon

[dwilli3038]

Joe,
The car turns over well. It seems to fire a little at the first few revolutions and then it turns as if it had no gas or no spark. And yess it was a thrill for it to start and to actualy drive it even though I just stayed in the neighborhood.

Thanks to all the others who made suggestions. Since the hood is still off, it will be quite as for my to try out your suggestions. Unless Saturday is a rainy day in GA I will be trying your advise and will let you know how it works.

Regards,
Daryl

Daryl
'64 230 SL
Serial # 508

[al_lieffring]

Daryl, you could cruise your Pagoda down to Bishop on Saturday. We could check out your hot start, see if there is any thing we can do to get it working.

Al  :O)

113-042-10-014715
built 11 Jan 66
904/396 blue, Ivory Tex
condition- rust bucket

[ja17]

Hello Daryl,

Good suggestions from these guys. Make sure you have a tester or 12 volt test light and a couple of jumper wires and you should be able to pinpoint the problem. Good Luck,

Joe

Joe Alexander
Blacklick, Ohio

[dwilli3038]

Al,

Thanks for the offer, but I am afrad to go to Bishob right now. I need to resole the hot start issue before I am comfortable enough to go the 2 miles to the nearst gast station and fill it up. Then I need to get some tires on it before I a ready to go fr at all. I do look forward to soon taking my Pogoda for drive over and see how you and Nickare prgressing on yours.



Daryl
'64 230 SL
Serial # 508

[dwilli3038]

This weekend the car started amazingly easy the first time. I just turned the key and it started right up. After is was warm I turned it off and followed the advise and depressed the gas 1/2 way it fired a little and then nothing. After cooling down it started easily. This time I tried jumping out the ballast resister, same results a little sputter at first then nothing. Once again after cool down it started easily. This time I tried energizing the cold start gas solenoid. Same results. I tried full throttle, I tried no throttle.

Any ideas of what to try next??

The neigbors are all liking the car driving around, and while letting it cool down those many times, I was able to get the hard top back together

Daryl
'64 230 SL
Serial # 508

[CarlG]

Two suggestions, first make sure that the electrical connection in the fuse box for the fuel pump is tight and also that the connections at the fuel pump are tight.  Second check the fuel filter.

1967 230sl (stick)

[ja17]

Hello Daryl,

Yes do check or change the fuel filter as Carl suggests.  If you have fuel and spark it should start. Test for lack of fuel by using a little starting fluid. If it starts then you have a fuel starvation problem. Test for lack of spark by holding the high tension coil wire near grounded metal to watch for spark.

Check back with the results.

Joe Alexander
Blacklick, Ohio

[ctaylor738]

Just to rule out an ignition problem, suggest putting a timing light on one of the cylinders when it's not starting.  Crank the engine and see if you are getting spark.

Chuck Taylor
1970 280SL #14076
Falls Church VA

[Mike Hughes]

Sometimes my 230SL gives me the same trouble. The best explanation I have been given is that hot engine heat-soaks the injector lines and creates a bit of a vapor lock.  This makes sense as I also have a "hot start" problem, even though engine has not been run for several hours, when the hood has been up at a car show exposing the engine compartment to the hot sun all day.  I can get it to fire up fairly quickly simply by waiting 30-45 seconds after turning on the ignition to give the electric feul pump enough time allow cool fuel to be circulated up to the injector pump.  Then I engage the starter while fully depressing the accelerator.  It will fire up and settle down to a smooth idle after 10-15 seconds on the first or second try.

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

[hands_aus]

Hi Mike Hughes,
The long prime time is an indicator that the valves of the injection pump are not holding pressure.

My 250sl does the same thing when cold, however it easily starts, when hot.

I installed the optional 'time' relay to help solve the problem.

It is my intention to replace the inj pump valves one day but I have higher priorities.

Bob Smith (Brisbane,Australia)
RHD,1967 early 250 SL, auto

[Benz Dr.]

It's a fuel flow or volume problem. I would look at how much fuel you have coming out of the return line or maybe the return line is partly blocked. A weak fuel pump will also cause hard starting until it cools off but will run OK as long as you're moving.
I've seen this many times before. Shut the engine off and it won't start again if you leave it for a short while. Leave it for 1/2 hour and it starts like usual.

Dan Caron's
 SL Barn
benzbarn@ebtech.net
 slbarn.mbz.org
  1 877 661 6061

[tobacco]

Daryl, I can't speak to all the W113s, but my 1971 USA-spec 280 SL's owner's manual is specific (p. 17) on how to start the "...lukewarm or warm engine:  accelerate simultaneously with starting operation."  

I press the accelerator to the floor while turning the ignition key, releasing the accelerator completely when the engine fires (which is almost instantly).  

While this may not apply to all or differently configured or earlier W113s, or to some of the problems cited in this thread, it's worth first discovering and trying out Mercedes' recommended re-starting technique -- in the hope you just may have a healthy system after all.

Bill Greffin
Chicago
#22375

[J. Huber]

For what its worth, in recent years, my car actually starts better warm than cold -- but only by a smidge. Fortunately both are doing what they should -- my cold start cranks about 2-3 seconds then catches (no throttle), my warm start is usually "bam" as soon as the ignition hits (again, no throttle). This warm aspect seems to stay that way most of the day (2 minutes after warm, or several hours)...

PS -- I didn't want to sound nana-na-na-na... trust me, it was not always that way. Just want to say it can happen. Good luck.

James
63 230SL

[bpossel]

James,

Mine starts in a similar way, except when cold...  When cold takes several cranks to start, no throttle.  Once started, then shut off, I turn my key 1x and it starts right up, no throttle.  When my car is shut off, the vacuum dashpot pushes up slightly on the throttle linkage, in other words, not resting flat against the idle stop.  Once started, the vacuum dashpot pulls inward and the linkage rests flat against the idle stop...  Not sure if this is normal, but seems to work ok...
Bob

bpossel  (Memphis, TN.)
'71 280SL  /  '97 E320

[dwilli3038]

Thanks for all the great ideas!

One of the other issues I had with the car was it seemed the battery did not hold a charge very well. I bought a new battery today. It cranks much faster. It now starts when hot. It seems to me it starts hard and takes longer than I would expect but it does start. Most likely there are some issues with the air fuel ratios. One of these weekends if Al is availabe I will take him up on his offer and drive over to Bishop to see if he can tweek it a little.

Daryl
'64 230 SL Buckeye Benz Scarlet interior and Grey top Serial # 508
'77 280SE

[91lux]

Hi
I experinced the same with my  64 230sl. It showed up to be very sensitive to the dwell angle/Breaker point gap.  If 10 degree of it was differcult to start warm and had a weak idle. Stopped when put on main lights etc. Should be 38 degree (+3 , -1). Operates best when when dwell angle  40 degree.I searched out and tryied a lof of things before this solved the problem, but as BBB says the ingnition shold be correct before you adjust the ignition pump, idle etc.

Best regards 91lux

64 230 sl

[al_lieffring]

Daryl

Give me a call and come on down.
cell # 706 338 0538

Al  

quote:Originally posted by dwilli3038

 One of these weekends if Al is availabe I will take him up on his offer and drive over to Bishop to see if he can tweek it a little.

Daryl
'64 230 SL Buckeye Benz Scarlet interior and Grey top Serial # 508
'77 280SE

113-042-10-014715
built 11 Jan 66
904/396 blue, Ivory Tex
condition- rust bucket

[Longtooth]

Gee... I have the same problem with warm engine... starts easily very shortly after turning off engine to brouse thru Home Depot tools or something, but wait an hour or while I'm at work all day and it takes several seconds of turning the crank to get it to start.  It starts immediately with cold engine though.... leaving parked overnight for even less time than it sits at work during the day.

I found though, that parking with nose downhill a bit reduces or even eliminates the time it takes to start when warm... and also notice that my electric fuel pump isn't 'whining' most of the time when I go to start it.... so I agree with Mike Hughes's diagnosis...

 

quote:Sometimes my 230SL gives me the same trouble. The best explanation I have been given is that hot engine heat-soaks the injector lines and creates a bit of a vapor lock. This makes sense as I also have a "hot start" problem, even though engine has not been run for several hours, when the hood has been up at a car show exposing the engine compartment to the hot sun all day. I can get it to fire up fairly quickly simply by waiting 30-45 seconds after turning on the ignition to give the electric feul pump enough time allow cool fuel to be circulated up to the injector pump. Then I engage the starter while fully depressing the accelerator. It will fire up and settle down to a smooth idle after 10-15 seconds on the first or second try.

When my electric fuel pump is working I let it hum for about 10 sec's when engine's warm then crank it right up.... so I guess I'd better check out why my electric fuel pump's intermittant, huh?.. just been to lazy and busy with a lot of other stuff going on and have been procrastinating... I'm hoping it's only a poor connection that's worked itself looser, but I have that sneaking feeling that won't be it.

BTW, it does the same thing (several second's cranking (on or off the throttle) when warm) even after timing the advance near dead-nuts.  That isn't to say though that spark which is a tad too retarded or too advanced won't exaccerabate a starting problem.... since I know by experience with my 327 (on my truck) that timing DOES make a difference.

Longtooth
67 250SL US #113-043-10-002163
'02 SL500 Sport