Borgweiser Posted November 3, 2011 Share Posted November 3, 2011 Time for former merc mechanic to jump in, from the above pic I assume it's a M104 and not M112 V6, from the lack of booster assistance it sounds like an air leak is causing the poor starting and poor running, air flow meter will not work and will give false readings if there are air leaks present. Infact the air flow meter may have been incorectly diagnosed last time around. pull plugs and coil leads to check for moisture, also check the coil packs have welds up the sides of them, if not get that done as it stops arcing. Factory specified cure for misfiring. Also if the thermostat is removed then you will smell the cats get sulphurish, blocked cats are a possibility but rare on this model as they are huge. It does sound like the inlet cam is too retarded, and these are on a magnetic plunger setup for advance, signal for this is from ecu, again if incorrect air mass and lambda readings + engine operating temp fluctuations it will effectively go into limp mode and not operate any fly by wire accesories. I would start by pulling plugs and check manifold and all vaccum hoses, also avoid Wellington star like the plague, not a single mechanic there was around when these were new, let alone had much experience or really care, I should know. Any more dramas let me know I will check it over for beer etc James Quote Link to comment Share on other sites More sharing options...
Unclejake Posted November 3, 2011 Author Share Posted November 3, 2011 Thanks man. I will check it out tonight and report back. I have been driving the car today and I suspect it is running on only four cylinders. The vaccum booster hasn't been a problem for me. The vehicle probably goes to a new owner on Sunday so there will no time for significant changes between then and now. It is indeed a W210 with the M104 engine. I wanted that earlier model engine as they are so solid. I will fit some new sparkplugs, check the coils and have a poke around for a vacuum leak tonight Quote Link to comment Share on other sites More sharing options...
Rhyscar Posted November 3, 2011 Share Posted November 3, 2011 i know nothing about these engines but from the sounds of your OP a weird backfire then never ran right after that, hard to start and doesn't run right sounds a bit like it has skipped a tooth or two on the camgears? just a far-fetched suggestion. Quote Link to comment Share on other sites More sharing options...
NaN Posted November 3, 2011 Share Posted November 3, 2011 jeez, .. helpful community aye I'm Kinda blown away to be honest, couldnt ask for a nicer group of postings! Quote Link to comment Share on other sites More sharing options...
Truenotch Posted November 4, 2011 Share Posted November 4, 2011 It's just because UJ is a sweetheart. Quote Link to comment Share on other sites More sharing options...
Unclejake Posted November 4, 2011 Author Share Posted November 4, 2011 Ha! Gents, thank you so much for your help. I pulled the coils off and changed all the spark-plugs. The thing now runs on six cylinders again. I took it for a short drive (still warm) and it is VASTLY improved. There was still a slight hesitation/stumble under load, but the car is 15382514237348246 times better. I opened the bonnet again and wriggled everything I had just touched but it all seemed good so I went next door to Pinkys and had two beers. I then drove the cold car the short distance home and it was awesome. Bloody awesome. Thanks heaps. The plugs were stuffed. I AM SO EXCITE Quote Link to comment Share on other sites More sharing options...
Truenotch Posted November 4, 2011 Share Posted November 4, 2011 . Quote Link to comment Share on other sites More sharing options...
Unclejake Posted November 5, 2011 Author Share Posted November 5, 2011 Just to update the thread: I took the car for a motorway burn today and it is running smoothly and strongly. The rough running issues seem to be completely sorted. It is running too cold at motorway speeds, so a thermostat will probably pay for itself in fuel savings, but apart from that it is running well. Awesome. Quote Link to comment Share on other sites More sharing options...
tim13 Posted November 5, 2011 Share Posted November 5, 2011 good effort , love a simple fix ! (just goes to show ALWAYS start with the basics) Quote Link to comment Share on other sites More sharing options...
Unclejake Posted November 5, 2011 Author Share Posted November 5, 2011 I always advise people to start with the simple things too, but the sulphur smell had me flummoxed. I thought the stench was a sign of a blocked cat convertor but clearly I was wrong. I fail at modern cars. Thanks for your advice wrt the coil removal Tim. It gave me the confidence to try. KKK also showed me a trick to opening the bonnet fully. OMG. I am such a retard. I have been banging my head on that grill and peering into the engine bay shadows for years, and now, 48 hours before we sell the car, I find out that you can open the bonnet to vertical and get it completely out of the way. What a fuckwit. LOL Quote Link to comment Share on other sites More sharing options...
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