Swampy442 Posted May 20, 2016 Share Posted May 20, 2016 Whilst putting the finishing touches Ellis's car and fit an FCD, I took the ECU off and discovered some brown liquid on a couple of the plugs. Opened the ECU up and there was some more pooled in the bottom cover of the case. It doesnt really smell of anything, slightly like electrolyte but not overly so, and is about as viscous as a light oil. The boards in the ECU seem fine, no obvious signs of a component failure. Any ideas? Could it have tracked in from the outside? The car also has an ABS/TRC fault so maybe this is related. I need to track down a good, working ECU to eliminate it Quote Link to comment Share on other sites More sharing options...
drift_bear Posted May 20, 2016 Share Posted May 20, 2016 I would clean it all up and see if it returns? Anymore signs of it out with the ecu cover? Heater matrix ok? Quote Link to comment Share on other sites More sharing options...
Suprakeith Posted May 20, 2016 Share Posted May 20, 2016 I had same thing with my ecu area getting wet and was down to heater matrix leaking Quote Link to comment Share on other sites More sharing options...
Burna Posted May 20, 2016 Share Posted May 20, 2016 Wile has had exactly the same thing recently! Weird Quote Link to comment Share on other sites More sharing options...
Burna Posted May 20, 2016 Share Posted May 20, 2016 Taste it, does it taste sweet? Quote Link to comment Share on other sites More sharing options...
mellonman Posted May 20, 2016 Share Posted May 20, 2016 Cam cover seals leaking and running down the bulk head into the cabin? Looks like engine oil to me Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted May 20, 2016 Share Posted May 20, 2016 Loom tape makes an excellent conduit for water some way away to wick down inside it and arrive at the end of the tape, but in this case, I would immediately suspect a leaking heater matrix. Taste the fluid, does it taste like anti freeze? Wash it all away with IPA, including the PCB's of the ecu itself if it's contaminated and leave to dry in a warm place. Quote Link to comment Share on other sites More sharing options...
Swampy442 Posted May 20, 2016 Author Share Posted May 20, 2016 Ill have a look tomorrow gents, thanks for the responses. Messers Burna and Wilson, Ive since cleaned it up so I cant taste it, but Ill give the plugs a good licking lol. Quote Link to comment Share on other sites More sharing options...
Swampy442 Posted May 20, 2016 Author Share Posted May 20, 2016 Cam cover seals leaking and running down the bulk head into the cabin? Looks like engine oil to me I don't think thats physically possible, but the bulkhead is dry and the loom is sealed from the engine bay with a diaphragm Quote Link to comment Share on other sites More sharing options...
Shane Posted May 21, 2016 Share Posted May 21, 2016 (edited) I would say its from a leak a somewhere at the other end of the loom, as crazy as it sounds over a period of time capillary action will cause exactly this. As mad as this will sound, on many of the Mercedes with auto transmission there is a electrical connector on the side of the transmission, the sealing O ring on the connector starts to leak fluid into the connector and over time ATF finds its way right up to the gearbox ecu. It happened to me and I couldn't believe it, but on taking the connector out of the gearbox sure enough there was transmission fluid in it. Not suggestion that's where your oil (and that's what it looks like form your photo) is coming from, but I would think its possible the same principle applies to other connectors/leaks. http://www.mbclub.co.uk/forums/engine/183115-so-many-issues-im-not-sure-where-start-whats-related.html http://www.pelicanparts.com/techarticles/Mercedes-Benz/23-TRANS-Automatic_Transmission_Fluid_Change/images_large/Pic14.JPG Edited May 21, 2016 by Shane (see edit history) Quote Link to comment Share on other sites More sharing options...
Shane Posted May 21, 2016 Share Posted May 21, 2016 Just to add to this, a quick look at this: http://www.mkivsupra.net/vbb/showthread.php?35919-ECU-Pinouts suggests that the middle connector block is what carries the ATF connections. Certainly worth a look down at the gearbox end to see if the connector is wet inside. Quote Link to comment Share on other sites More sharing options...
Swampy442 Posted May 21, 2016 Author Share Posted May 21, 2016 Thanks for the input Shane, but Im 100% certain any leak, should there be one, is internal. I comprehend capillary action but the gearbox is a fair distance away, and downhill, gravity would win in that scenario. Met the boss man today and Im going to have a check under he dash for any leaks in the heater system Quote Link to comment Share on other sites More sharing options...
Shane Posted May 22, 2016 Share Posted May 22, 2016 Thanks for the input Shane, but Im 100% certain any leak, should there be one, is internal. I comprehend capillary action but the gearbox is a fair distance away, and downhill, gravity would win in that scenario. Met the boss man today and Im going to have a check under he dash for any leaks in the heater system Yes I know what you are saying and until I saw it I thought it was highly unlikely that fluid could be drawn up about 2.5 metres upwards to the foot well of the car, but in the case of the Mercs it happens, I still find it pretty incredible. I guess the first step is to try and identify what the fluid is. Quote Link to comment Share on other sites More sharing options...
Dnk Posted May 22, 2016 Share Posted May 22, 2016 Too rule out Shanes possible cause can't you carefully cut open the loom for the gearbox to see if there's any ATF away from the plug Quote Link to comment Share on other sites More sharing options...
Swampy442 Posted May 22, 2016 Author Share Posted May 22, 2016 OK, will do Quote Link to comment Share on other sites More sharing options...
mellonman Posted May 22, 2016 Share Posted May 22, 2016 I still say thats engine oil by the look of it, or its very very bad transmission oil to be that black , coolent is just not that black or thick. I would say maybe cam sensors are leak and its traveling from the loom that way or the cam cover seal leaking onto knock sensors or injector plugs Quote Link to comment Share on other sites More sharing options...
keron Posted May 22, 2016 Share Posted May 22, 2016 ive seen this a few times now....not this bad though. all the ones I seen were engine oil.... as it was in the loom to so suspect cps or even the oil pressure switch pissing out and into the casing..... once those pressure switches go, they go....pushes all the oil right through the one single wire....I mentioned it to ellis the other day when he came over too Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted May 22, 2016 Share Posted May 22, 2016 I agree, definitely looks like engine oil to me, however how it got there I have no idea, surly a dip of the finger will confirm, and failing that the taste test. Quote Link to comment Share on other sites More sharing options...
wile e coyote Posted May 22, 2016 Share Posted May 22, 2016 Hi Yes I had similar Mines a vvti tiptronic I cleaned connector and fitted my spare ecu to be on the safe side Interesting read I'm going to investigate it further in the looms HD Quote Link to comment Share on other sites More sharing options...
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