250 won't start

[Ian45]

A few weeks ago, my 250 stalled as I was manouvreing on the driveway and refused to start again. I haven't had chance to investigate since but last weekend a mechanic friend came around and we went through a fault finding process.

The engine is turning but the makes no attempt whatsoever to fire up.

The points and plugs have been changed as the car was ready for servicing anyway. The condenser was also replaced. There is a good spark to the plugs. There is a strong smell of fuel and it certainly appears to reaching the injectors, but as a double check we manually injected some fuel into the inlet manifold and still it made no attempt to fire.

Any suggestions please ?

Ian
1967 250SL
Derby,England

[merrill]

Ian,
If you have a ballast resister in line to the coil,  jumper it.
If the car starts up, you may have a low battery or a voltage regulator that is failing.

Check the voltage levels before and after the ballast resister.
If the voltage after is less than 9 V you may have problems starting.

matt

Matt
66 230 sl - "white"
78 300 D - Blue
98 C230

[waltklatt]

Ian,  You say you have fuel at the injectors?  But how about inside the cylinders?  remove the plugs and see if there is a smell or wetness on the plug ends.  If they are dry, you probably have water or debris inside the injectors blocking them.  Did you do anything like replace the filters, clean out the tank or filled with bad gas?
Then check the electrics around the coil like Matt says.  Is the electric pump humming in the back near the rear axle?
Walter
1967 220SL-diesel
PS also check the archives for other hints, tips and tricks.  There is a ton of info there.

[Naj ✝︎]

Ian,
Did you have the distributor out when you replaced the points/condenser?
It may not have gone all the way home and therefore not turning with the engine...
Just a thought

naj

68 280SL

[ja17]

Hello Ian,

If you have fuel, spark on time and compression it will start. Make sure as Naj has mentioned to see if the distributor has jumped time. Is the rotor turning? Also remove the oil filler cap and make sure the camshaft is turning, Measure fuel pressure or give it a shot of starting fluid to see if fuel delivery is the problem.

Joe Alexander
Blacklick, Ohio

[Ian45]

Thanks for the tips everyone. Please keep them coming. It may be after Christmas now before I get chance to have another go, but I'm making a note of all your suggestions.

Ian
1967 250SL
1998 SLK230
Derby,England

[Naj ✝︎]

Ian,
This is related to what Joe Alexander said but does the oil pressure gage go up when you crank the engine???

naj

68 280SL

[glennard]

Ian, Thinking about a London trip at Xmas.  Where is Derby from London?

[Cees Klumper]

I would put my bet on the ignition timing. Keep us posted please!

Cees ("Case") Klumper in Amsterdam
'69 white 280 SL automatic