Cold Starting was slow this morning

[FRITZ68]

Over the weekend, I drove the '68 280SL about 40 miles and twice (a warm start) engine "bucked" while cranking, as if the timing was too far advanced.  Other times no problems at all.  Somewhat of a concern and no consistency with the  issue.  I am thinking that I may want my mechanic to slightly retard the timing (emphasis on "slightly").

I let the car sit in the garage all night and this afternoon tried to start it, and it was trying very hard not to cooperate, but finally started.  This evening I tried a different technique - I turned on the key and let the electric fuel pump run for about 30 seconds and then cranked it and it started immediately.  Is this the way that this car should be started on a cold start?

I am using premium fuel, but here in Ohio we have about 10% Ethanol in the fuel.

This is the car that we recently repainted and  attached are some pictures taken in my dirveway today.  A beautiful car, so hope that I can get these minor issued behind me so that my wife can enjoy the car.  Looking for some ideas.

Thanks, Fritz

[ja17]

Hello Fritz,

Try setting the timing at 30 BTDC at 3,000 rpms. Then go back and check the timing at an idle. If the idle specs are way off , most likely you have a vacuume retard issue (vac. leak, bad vac. cell, bad relay, sensor  or change-over, rpm relay).

Improper timing can cause, hard starting, shifting problems, lack of power and hot running.

[FRITZ68]

Thanks a lot Joe - I will have my mechanic take a look at the things that you suggested.

However, this morning the car sat overnight in my garage and I just tried my "new method" of turning on key to get the electric fuel pump running (for 15 seconds).  At the end of 15 seconds I turned the key furher to engage the starter, and the car started immediately.  Is it possible that this is the way it should be done?   Most of my other antique cars have carburetors and require one or two pumps of the gas on a cold start to set the choke, and if the carburetor floods, hold gas pedal all the way to the floor.  Driving a Mercedes is new to me, so am wondering if there are any little secrets in regard to starting the car?  Any ideas will be greatly appreciated.

Fritz

[ctaylor738]

In my experience you need to find a technique that works for your car.  Letting the pump run for a few seconds is something I do automatically along with depressing the accelerator an inch or so.  Cold starts are usually not a problem if the cold start valve is working. 

Hot starts are all over the map.  Some fire on the turn of the key, others grind away until you fear running out of battery.  One technique for hard hot starters is to let the pump run, floor the accelerator and crank (and carry your cell phone).

[71Beige280SL]

I had a 1976 Volkswagon Scirocco with fuel injection. It was always a nightmare on warm starts due to vapor locks in the fuel injection system. Do our cars suffer from this issue? 

[FRITZ68]

Hot starts are all over the map.  Some fire on the turn of the key, others grind away until you fear running out of battery.  One technique for hard hot starters is to let the pump run, floor the accelerator and crank (and carry your cell phone).

In addition to the cell phone, here is what I keep in most of my antique cars (in addition to a fire extinguisher and small tool kit).

Fritz

[ja17]

Fifeteen seconds is a bit long.  Normally, waiting a few seconds with  the ignition on before cranking is sufficient. The fuel systems need a brief period to pressurize with fuel in the injection pump. No accelerator pedal works with most. You  should be able to reach in the car and just turn the key after a few seconds. It should start and run on its own with very little cranking.

A fuel pressure and volume check can help pinpoint some problems. If you are not set-up to do this, the following procedures should cure your starting problems.............

If the engine has to crank too much, most likely you have a fuel delivery or a starting aid problem.  There is a list of things to check. The main fuel filter should be fresh.  Start with the fuel screen in the gas tank (it is on the drain plug). Next the fuel screen on the intake of the electric fuel pump should be checked. It is small and is easily clogged.  Clean the screen on the Cold Starting Valve (CSV) on the intake.It is built into the fitting of the cold starting valve. It is also tiny and easily restricted. Check to make sure the valve int the (CSV) is free while you have the fitting off.  Your CSV will activate during hot starts on some models for different lengths of time. It will also activate longer in colder temperatures. There are charts on "The Starting Aid Tour" showing the function of the different systems.

After all is back together you can check your starting aids with a test light.  Depending on the year and version, they perform differently. All CSVs should activate when the engine is cold. Check the function with a test light during a cold start.  Next check the injection pump starting Solenoid. These should activate whenever the starter is engaged. Check it with the test light during any start.

If your injection is set too lean it could also cause hard starting. Perform the "Split Linkage Mixture Test" to check the mixture.  

Lastly, the ignition must be healthy. A weak spark during initial starting procedures will cause starting issues. Make sure that your spark plugs are non resistor, your plug wires are non carbon  and you have the correct coil and ballast resistor for your ignition.

If you find that one or more of your starting aids are not working, get back with us and we will help you get them going.  If you need more details let us know. A lot to digest!

Joe Alexander (ja17)
Blacklick, Ohio

[Peter van Es]

You could try with this: Engine Starting Aid Tour. For Full Members, all the condensed knowledge of ja17 and other esteemed members...

[FRITZ68]

Thank you Peter - lots of great information, which I printed for reference.  In the meantime, here is how I started the car since receiving so much help on this forum:

I turn the key on far enough to activate the electric fuel pump, leaving it in that position for about 5 seconds.  I push the gas pedal down about 1" or less, then turn key further to crank engine.  It starts immediately.  I tried this method yesterday morning, late last night, and again this morning and it started like a new car (within one second).

I should mention that I previously had the car at a nearby certified mechanical shop about 2 weeks ago for a full tuneup (new spark plugs, spark plug wires, points, condenser, distributor cap, set timing, etc. and previously a new coil).  I am not exactly sure what was done, but the shop has some serious equipment to set the timing/dwell, etc.   Most of my problem with the cold start was trying to start the car immediately (without waiting for the electric fuel pump to activate), so I guess I over reacted.  I have many antique cars of verious types (from 1917 up) and all have their special way of starting.  I plan to start placing a card in each car to provide this information for the future.  I have several Model  A Fords, and none of our younger guys understand how to get them started (push steering column timing lever up to retard the timing).

So for now, I feel that I have the problem solved.... thanks to so much help on this forum.  I just took 3 pictures of the engine this morning.

Fritz