Posted by John kennard on November 5, 2009, 3:50 pm
Year of Manufacture *: 2004 Engine Code or CC *: 449 ( Optional ) ECU Type: Bosch ME 2.1 ( Optional ) Scanner Used: Autodiagnose / Hannatech
Hi I have this one which came back a week after servicing with bad starting. It is strange in that when you go to start you have to wind the engine over repeatedly 5-6 times while it tries to sort of start then all of a sudden it fires into life as if nothing is wrong.
The first code read came up with P201D Self adaptation of mixture formation (Fuel Trim). After clearing and a further road test where the vehicle felt flat to start with but regained its potential after a quick thrash, the re-read of the system produced P201C Misfire detected Cyl 1. I put a COP tester on each coil, on No. 3 coil it appeared to be giving an erratic spark. I fitted a new coil to No. 3 this made no difference so I refitted no. 3 coil & replaced No. 1 with the new coil which came up on the code reader, this now immediately made No. 2 coil misfire continuously so I fitted the coil from No. 1 into No. 2 cyl and car started and ran perfectly leaving 2 more codes in the system P2025 T1/1-4 Ign Coil & P201B Misfire detected.
The problem is that the 6-7 crankings to start has returned but runs perfectly when it starts and has not logged any more codes. Question is do I need to get on & replace the 3 coils not replaced even though the COP tester shows sparking from all coils even when cranking but not starting. Similarly does anyone recognize the symptoms described here. John Kennard.
Sorry if this is something you have already checked.
Had a S500 recently with similar symptoms and the fuel pressure was way down, I know this wouldn't cause a full miss on one cylinder, but you never know.
Steve
Fixed #
Posted by John kennard on November 11, 2009, 5:30 pm, in reply to "Re: Mercedes SLK 230 (170) Poor Starting" Message modified by board administrator November 12, 2009, 2:27 pm
Thank you Steve the fuel pressure was down due to a faulty Mann fuel filter WK720 which caused misfiring when the engine finally started but appeared to run normally if a little under par. I expect the weak mixture was causing the misfire & definitely the poor starting.
The result is that our supplier is going to pickup the bill for all the hassle involved & refund the faulty filter. Apparently Mann has recalled all of these part no's off the shelf. Thank you for your help. John Kennard.
on November 5, 2009, 9:20 pm, in reply to "