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Mercedes Benz 300SL 1990 - No spark, but turns over - Fixed #

Posted by Roy Bryant on February 20, 2013, 2:48 pm

Year of Manufacture *: 1990

Hi Guys

My 300sl has decided not to start after my lad hoovered it out, the only thing that he moved was the drivers seat, which the forward and backwards movement did not work before hand.
No spark from coil but has one when flashed. Turns over, plugs are dry but hear fuel pump start with ign on. Seems to be pulse from c/shaft sensor.
Fuses ok, relay fuse ok, poss ign module, any ideas how to test? Dont understand not starting after hoovering, run fine for many years.
Codes flash no 3 temp sensor, not sure which one as there seems to be four on it put disconnected all and no difference.
Battery ok and door locks and immobilizer seems to be working.
Any ideas please?

regards

Roy Bryant

Re: Merc 300SL no spark, turns over

Posted by andyhyoung <iframe src='https://members4.boardhost.com/ukautotalk/info/user=UKAT5148' width='330' height='300' border=0 style='border:none;'> on February 20, 2013, 6:38 pm, in reply to "Merc 300SL no spark, turns over"
Andrew Young

Can you confirm the model type .Is it a wdb 107 or 129.Year 1990 is the change over model.

Re: Merc 300SL no spark, turns over

Posted by Roy Bryant on February 20, 2013, 9:54 pm, in reply to "Re: Merc 300SL no spark, turns over"
Edited by board administrator February 23, 2013, 2:16 pm

Hi Andy it is a 129
Thanks

Re: Merc 300SL no spark, turns over

Posted by Martin Simonsohn on February 21, 2013, 6:07 pm, in reply to "Re: Merc 300SL no spark, turns over"
Edited by board administrator February 23, 2013, 2:17 pm

Hi

Have you tested the multi function relay behind the battery on the ns bulkhead engine bay?
the relay is engine control and fuel pump relay
they suffer with dry joints

Martin

Re: Merc 300SL no spark, turns over

Posted by andyhyoung <iframe src='https://members4.boardhost.com/ukautotalk/info/user=UKAT5148' width='330' height='300' border=0 style='border:none;'> on February 21, 2013, 6:16 pm, in reply to "Re: Merc 300SL no spark, turns over"
Andrew Young

All the engine electronics are housed under the plastic cover,left hand engine bay,in front of screen.There are no electronics under the seat for the engine.If I recall,these were not fitted with any factory install immobiliser system (at this era),so any system currently fitted will be aftermarket.Btw battery in boot on these.

Re: Merc 300SL no spark, turns over

Posted by Roy Bryant <iframe src='https://members4.boardhost.com/ukautotalk/info/user=UKAT1300' width='330' height='300' border=0 style='border:none;'> on February 26, 2013, 1:01 pm, in reply to "Re: Merc 300SL no spark, turns over"

Hi Martin, the battery is in the boot, when I turn the ignition on there is a fuel pump noise for two seconds but the plugs do not get wet

Re: Merc 300SL no spark, turns over

Posted by Roy Bryant <iframe src='https://members4.boardhost.com/ukautotalk/info/user=UKAT1300' width='330' height='300' border=0 style='border:none;'> on February 26, 2013, 1:04 pm, in reply to "Re: Merc 300SL no spark, turns over"

Hi Andy, not sure if there is an immobilliser fitted does anyone know how to test the ignition control module on n/s inner wing?

Re: Merc 300SL no spark, turns over

Posted by martin simonsohn <iframe src='https://members4.boardhost.com/ukautotalk/info/user=ukat3223' width='330' height='300' border=0 style='border:none;'> on February 26, 2013, 3:28 pm, in reply to "Re: Merc 300SL no spark, turns over"
Martin Simonsohn

hi roy i havnt got any data/wiring info to cover this model im not sure how to help is the pump running with engine cranking if it isnt might be crank csensor
i know on some mercedes the engine ecu is nsf foot well under carpet if its not there it might be nsf wing in a box sure there is a fuse on the voltage protection relay
sorry im a bit vauge but my eyes cant see the job

Fixed #

Posted by Roy Bryant on April 14, 2013, 4:03 pm, in reply to "Re: Merc 300SL no spark, turns over"
Edited by board administrator April 17, 2013, 2:44 pm

Fixed: got hold of used ignition control module with slightly different numbers but same connections which was for a 6 cyl and it started first time. was lucky getting one for £20 as they ranged from £500 to $4000.
Thanks for input guys
Roy

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